Add UI to add/remove/list journal members.

Only owners of a journal are allowed to control and view its members.

app/src/main/AndroidManifest.xml

@@ -184,6 +184,7 @@
             android:parentActivityName=".ui.AccountsActivity">
         </activity>
         <activity android:name=".ui.ViewCollectionActivity"/>
+        <activity android:name=".ui.CollectionMembersActivity"/>
         <activity android:name=".ui.importlocal.ImportActivity"/>
         <activity android:name=".ui.AccountSettingsActivity"/>
         <activity android:name=".ui.CreateCollectionActivity"/>

app/src/main/java/com/etesync/syncadapter/journalmanager/Crypto.java

@@ -115,6 +115,12 @@ public class Crypto {
         public static byte[] getKeyFingerprint(byte[] pubkey) {
             return sha256(pubkey);
         }
+
+        public static String getPrettyKeyFingerprint(byte[] pubkey) {
+            byte[] fingerprint = Crypto.AsymmetricCryptoManager.getKeyFingerprint(pubkey);
+            String fingerprintString = Hex.toHexString(fingerprint).toLowerCase();
+            return fingerprintString.replaceAll("(.{4})", "$1   ");
+        }
     }
 
     public static class CryptoManager {
@@ -125,6 +131,7 @@ public class Crypto {
         private final byte version;
         private byte[] cipherKey;
         private byte[] hmacKey;
+        private byte[] derivedKey;
 
         private void setDerivedKey(byte[] derivedKey) {
             cipherKey = hmac256("aes".getBytes(Charsets.UTF_8), derivedKey);
@@ -133,14 +140,13 @@ public class Crypto {
 
         public CryptoManager(int version, AsymmetricKeyPair keyPair, byte[] encryptedKey) {
             Crypto.AsymmetricCryptoManager cryptoManager = new Crypto.AsymmetricCryptoManager(keyPair);
-            byte[] derivedKey = cryptoManager.decrypt(encryptedKey);
+            derivedKey = cryptoManager.decrypt(encryptedKey);
 
             this.version = (byte) version;
             setDerivedKey(derivedKey);
         }
 
         public CryptoManager(int version, @NonNull String keyBase64, @NonNull String salt) throws Exceptions.IntegrityException, Exceptions.VersionTooNewException {
-            byte[] derivedKey;
             if (version > Byte.MAX_VALUE) {
                 throw new Exceptions.IntegrityException("Version is out of range.");
             } else if (version > Constants.CURRENT_VERSION) {
@@ -238,6 +244,11 @@ public class Crypto {
             hmac.doFinal(ret, 0);
             return ret;
         }
+
+        public byte[] getEncryptedKey(AsymmetricKeyPair keyPair, byte[] publicKey) {
+            AsymmetricCryptoManager cryptoManager = new AsymmetricCryptoManager(keyPair);
+            return cryptoManager.encrypt(publicKey, derivedKey);
+        }
     }
 
     static String sha256(String base) {

app/src/main/java/com/etesync/syncadapter/journalmanager/JournalManager.java

@@ -144,6 +144,12 @@ public class JournalManager extends BaseManager {
             super();
         }
 
+        public static Journal fakeWithUid(String uid) {
+            Journal ret = new Journal();
+            ret.setUid(uid);
+            return ret;
+        }
+
         public Journal(Crypto.CryptoManager crypto, String content, String uid) {
             super(crypto, content, uid);
             hmac = calculateHmac(crypto);

app/src/main/java/com/etesync/syncadapter/ui/AccountActivity.java

@@ -217,9 +217,7 @@ public class AccountActivity extends AppCompatActivity implements Toolbar.OnMenu
         AccountSettings settings = null;
         try {
             settings = new AccountSettings(this, account);
-            byte[] fingerprint = Crypto.AsymmetricCryptoManager.getKeyFingerprint(settings.getKeyPair().getPublicKey());
-            String fingerprintString = Hex.toHexString(fingerprint).toLowerCase();
-            return fingerprintString.replaceAll("(.{4})", "$1   ");
+            return Crypto.AsymmetricCryptoManager.getPrettyKeyFingerprint(settings.getKeyPair().getPublicKey());
         } catch (Exception e) {
             e.printStackTrace();
             return null;

app/src/main/java/com/etesync/syncadapter/ui/AddMemberFragment.java

@@ -0,0 +1,174 @@
+package com.etesync.syncadapter.ui;
+
+import android.accounts.Account;
+import android.app.Dialog;
+import android.app.ProgressDialog;
+import android.content.DialogInterface;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.v4.app.DialogFragment;
+import android.support.v7.app.AlertDialog;
+
+import com.etesync.syncadapter.AccountSettings;
+import com.etesync.syncadapter.Constants;
+import com.etesync.syncadapter.HttpClient;
+import com.etesync.syncadapter.InvalidAccountException;
+import com.etesync.syncadapter.R;
+import com.etesync.syncadapter.journalmanager.Crypto;
+import com.etesync.syncadapter.journalmanager.JournalManager;
+import com.etesync.syncadapter.journalmanager.UserInfoManager;
+import com.etesync.syncadapter.model.CollectionInfo;
+
+import lombok.RequiredArgsConstructor;
+import okhttp3.HttpUrl;
+import okhttp3.OkHttpClient;
+
+public class AddMemberFragment extends DialogFragment {
+    final static private String KEY_MEMBER = "memberEmail";
+    private Account account;
+    private AccountSettings settings;
+    private OkHttpClient httpClient;
+    private HttpUrl remote;
+    private CollectionInfo info;
+    private String memberEmail;
+    private byte[] memberPubKey;
+
+    public static AddMemberFragment newInstance(Account account, CollectionInfo info, String email) {
+        AddMemberFragment frag = new AddMemberFragment();
+        Bundle args = new Bundle(1);
+        args.putParcelable(Constants.KEY_ACCOUNT, account);
+        args.putSerializable(Constants.KEY_COLLECTION_INFO, info);
+        args.putString(KEY_MEMBER, email);
+        frag.setArguments(args);
+        return frag;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        account = getArguments().getParcelable(Constants.KEY_ACCOUNT);
+        info = (CollectionInfo) getArguments().getSerializable(Constants.KEY_COLLECTION_INFO);
+        memberEmail = getArguments().getString(KEY_MEMBER);
+        try {
+            settings = new AccountSettings(getContext(), account);
+            httpClient = HttpClient.create(getContext(), account);
+        } catch (InvalidAccountException e) {
+            e.printStackTrace();
+        }
+        remote = HttpUrl.get(settings.getUri());
+
+        new MemberAdd().execute();
+    }
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        ProgressDialog progress = new ProgressDialog(getContext());
+        progress.setTitle(R.string.collection_members_adding);
+        progress.setMessage(getString(R.string.please_wait));
+        progress.setIndeterminate(true);
+        progress.setCanceledOnTouchOutside(false);
+        setCancelable(false);
+        return progress;
+    }
+
+    private class MemberAdd extends AsyncTask<Void, Void, MemberAdd.AddResult> {
+        @Override
+        protected AddResult doInBackground(Void... voids) {
+            try {
+                UserInfoManager userInfoManager = new UserInfoManager(httpClient, remote);
+
+                Crypto.CryptoManager crypto = new Crypto.CryptoManager(info.version, settings.password(), info.uid);
+
+                memberPubKey = userInfoManager.get(crypto, memberEmail).getPubkey();
+                return new AddResult(null);
+            } catch (Exception e) {
+                return new AddResult(e);
+            }
+        }
+
+        @Override
+        protected void onPostExecute(AddResult result) {
+            if (result.throwable == null) {
+                String fingerprint = Crypto.AsymmetricCryptoManager.getPrettyKeyFingerprint(memberPubKey);
+
+                new AlertDialog.Builder(getActivity())
+                        .setIcon(R.drawable.ic_info_dark)
+                        .setTitle(R.string.trust_fingerprint_title)
+                        .setMessage(fingerprint)
+                        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+                                new MemberAddSecond().execute();
+                            }
+                        })
+                        .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+                            }
+                        }).show();
+            } else {
+                new AlertDialog.Builder(getActivity())
+                        .setIcon(R.drawable.ic_error_dark)
+                        .setTitle(R.string.collection_members_add_error)
+                        .setMessage(result.throwable.getMessage())
+                        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+
+                            }
+                        }).show();
+                dismiss();
+            }
+        }
+
+        @RequiredArgsConstructor
+        class AddResult {
+            final Throwable throwable;
+        }
+    }
+
+    private class MemberAddSecond extends AsyncTask<Void, Void, MemberAddSecond.AddResultSecond> {
+        @Override
+        protected AddResultSecond doInBackground(Void... voids) {
+            try {
+                JournalManager journalsManager = new JournalManager(httpClient, remote);
+
+                JournalManager.Journal journal = JournalManager.Journal.fakeWithUid(info.uid);
+                Crypto.CryptoManager crypto = new Crypto.CryptoManager(info.version, settings.password(), info.uid);
+
+                byte[] encryptedKey = crypto.getEncryptedKey(settings.getKeyPair(), memberPubKey);
+                JournalManager.Member member = new JournalManager.Member(memberEmail, encryptedKey);
+                journalsManager.addMember(journal, member);
+                return new AddResultSecond(null);
+            } catch (Exception e) {
+                return new AddResultSecond(e);
+            }
+        }
+
+        @Override
+        protected void onPostExecute(AddResultSecond result) {
+            if (result.throwable == null) {
+                ((Refreshable) getActivity()).refresh();
+            } else {
+                new AlertDialog.Builder(getActivity())
+                        .setIcon(R.drawable.ic_error_dark)
+                        .setTitle(R.string.collection_members_add_error)
+                        .setMessage(result.throwable.getMessage())
+                        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+
+                            }
+                        }).show();
+            }
+            dismiss();
+        }
+
+        @RequiredArgsConstructor
+        class AddResultSecond {
+            final Throwable throwable;
+        }
+    }
+}

app/src/main/java/com/etesync/syncadapter/ui/CollectionMembersActivity.java

@@ -0,0 +1,153 @@
+package com.etesync.syncadapter.ui;
+
+import android.accounts.Account;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.v4.app.DialogFragment;
+import android.support.v7.app.AlertDialog;
+import android.support.v7.app.AppCompatActivity;
+import android.text.InputType;
+import android.view.MenuItem;
+import android.view.View;
+import android.widget.EditText;
+import android.widget.TextView;
+
+import com.etesync.syncadapter.App;
+import com.etesync.syncadapter.R;
+import com.etesync.syncadapter.model.CollectionInfo;
+import com.etesync.syncadapter.model.JournalEntity;
+import com.etesync.syncadapter.resource.LocalCalendar;
+
+import io.requery.Persistable;
+import io.requery.sql.EntityDataStore;
+
+public class CollectionMembersActivity extends AppCompatActivity implements Refreshable {
+    public final static String EXTRA_ACCOUNT = "account",
+            EXTRA_COLLECTION_INFO = "collectionInfo";
+
+    private Account account;
+    private JournalEntity journalEntity;
+    private CollectionMembersListFragment listFragment;
+    protected CollectionInfo info;
+
+    public static Intent newIntent(Context context, Account account, CollectionInfo info) {
+        Intent intent = new Intent(context, CollectionMembersActivity.class);
+        intent.putExtra(CollectionMembersActivity.EXTRA_ACCOUNT, account);
+        intent.putExtra(CollectionMembersActivity.EXTRA_COLLECTION_INFO, info);
+        return intent;
+    }
+
+    @Override
+    public void refresh() {
+        EntityDataStore<Persistable> data = ((App) getApplicationContext()).getData();
+
+        journalEntity = JournalEntity.fetch(data, info.getServiceEntity(data), info.uid);
+        if ((journalEntity == null) || journalEntity.isDeleted()) {
+            finish();
+            return;
+        }
+
+        info = journalEntity.getInfo();
+
+        setTitle(R.string.collection_members_title);
+
+        final View colorSquare = findViewById(R.id.color);
+        if (info.type == CollectionInfo.Type.CALENDAR) {
+            if (info.color != null) {
+                colorSquare.setBackgroundColor(info.color);
+            } else {
+                colorSquare.setBackgroundColor(LocalCalendar.defaultColor);
+            }
+        } else {
+            colorSquare.setVisibility(View.GONE);
+        }
+        findViewById(R.id.progressBar).setVisibility(View.GONE);
+
+        final TextView title = (TextView) findViewById(R.id.display_name);
+        title.setText(info.displayName);
+
+        final TextView desc = (TextView) findViewById(R.id.description);
+        desc.setText(info.description);
+
+        if (listFragment != null) {
+            listFragment.refresh();
+        }
+    }
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        setContentView(R.layout.view_collection_members);
+
+        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
+
+        account = getIntent().getExtras().getParcelable(EXTRA_ACCOUNT);
+        info = (CollectionInfo) getIntent().getExtras().getSerializable(EXTRA_COLLECTION_INFO);
+
+        refresh();
+
+        // We refresh before this, so we don't refresh the list before it was fully created.
+        if (savedInstanceState == null) {
+            listFragment = CollectionMembersListFragment.newInstance(account, info);
+            getSupportFragmentManager().beginTransaction()
+                    .add(R.id.list_entries_container, listFragment)
+                    .commit();
+        }
+    }
+
+    public void onAddMemberClicked(View v) {
+        final EditText input = new EditText(this);
+        input.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_EMAIL_ADDRESS);
+        AlertDialog.Builder dialog = new AlertDialog.Builder(this)
+                .setTitle(R.string.collection_members_add)
+                .setIcon(R.drawable.ic_account_add_dark)
+                .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        DialogFragment frag = AddMemberFragment.newInstance(account, info, input.getText().toString());
+                        frag.show(getSupportFragmentManager(), null);
+                    }
+                })
+                .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                    }
+                });
+        dialog.setView(input);
+        dialog.show();
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        if (item.getItemId() == android.R.id.home) {
+            if (!getSupportFragmentManager().popBackStackImmediate()) {
+                finish();
+            }
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+
+        App app = (App) getApplicationContext();
+        if (app.getCertManager() != null)
+            app.getCertManager().appInForeground = true;
+
+        refresh();
+    }
+
+    @Override
+    protected void onPause() {
+        super.onPause();
+
+        App app = (App) getApplicationContext();
+        if (app.getCertManager() != null)
+            app.getCertManager().appInForeground = false;
+    }
+}

app/src/main/java/com/etesync/syncadapter/ui/CollectionMembersListFragment.java

@@ -0,0 +1,164 @@
+package com.etesync.syncadapter.ui;
+
+import android.accounts.Account;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.v4.app.DialogFragment;
+import android.support.v4.app.ListFragment;
+import android.support.v7.app.AlertDialog;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
+import android.widget.TextView;
+
+import com.etesync.syncadapter.AccountSettings;
+import com.etesync.syncadapter.App;
+import com.etesync.syncadapter.Constants;
+import com.etesync.syncadapter.HttpClient;
+import com.etesync.syncadapter.R;
+import com.etesync.syncadapter.journalmanager.JournalManager;
+import com.etesync.syncadapter.model.CollectionInfo;
+import com.etesync.syncadapter.model.EntryEntity;
+import com.etesync.syncadapter.model.JournalEntity;
+import com.etesync.syncadapter.model.JournalModel;
+
+import java.util.List;
+
+import io.requery.Persistable;
+import io.requery.sql.EntityDataStore;
+import lombok.RequiredArgsConstructor;
+import okhttp3.HttpUrl;
+import okhttp3.OkHttpClient;
+
+public class CollectionMembersListFragment extends ListFragment implements AdapterView.OnItemClickListener, Refreshable {
+    private EntityDataStore<Persistable> data;
+    private Account account;
+    private CollectionInfo info;
+    private JournalEntity journalEntity;
+
+    private TextView emptyTextView;
+
+    public static CollectionMembersListFragment newInstance(Account account, CollectionInfo info) {
+        CollectionMembersListFragment frag = new CollectionMembersListFragment();
+        Bundle args = new Bundle(1);
+        args.putParcelable(Constants.KEY_ACCOUNT, account);
+        args.putSerializable(Constants.KEY_COLLECTION_INFO, info);
+        frag.setArguments(args);
+        return frag;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        data = ((App) getContext().getApplicationContext()).getData();
+        account = getArguments().getParcelable(Constants.KEY_ACCOUNT);
+        info = (CollectionInfo) getArguments().getSerializable(Constants.KEY_COLLECTION_INFO);
+        journalEntity = JournalModel.Journal.fetch(data, info.getServiceEntity(data), info.uid);
+    }
+
+    @Override
+    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+        View view = inflater.inflate(R.layout.collection_members_list, container, false);
+
+        //This is instead of setEmptyText() function because of Google bug
+        //See: https://code.google.com/p/android/issues/detail?id=21742
+        emptyTextView = (TextView) view.findViewById(android.R.id.empty);
+        return view;
+    }
+
+    @Override
+    public void refresh() {
+        new JournalMembersFetch().execute();
+    }
+
+    @Override
+    public void onViewCreated(View view, Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+
+        refresh();
+
+        getListView().setOnItemClickListener(this);
+    }
+
+    @Override
+    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+        final JournalManager.Member member = (JournalManager.Member) getListAdapter().getItem(position);
+
+        new AlertDialog.Builder(getActivity())
+                .setIcon(R.drawable.ic_info_dark)
+                .setTitle(R.string.collection_members_remove_title)
+                .setMessage(getString(R.string.collection_members_remove, member.getUser()))
+                .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        DialogFragment frag = RemoveMemberFragment.newInstance(account, info, member.getUser());
+                        frag.show(getFragmentManager(), null);
+                    }
+                })
+                .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                    }
+                }).show();
+    }
+
+    class MembersListAdapter extends ArrayAdapter<JournalManager.Member> {
+        MembersListAdapter(Context context) {
+            super(context, R.layout.collection_members_list_item);
+        }
+
+        @Override
+        @NonNull
+        public View getView(int position, View v, @NonNull ViewGroup parent) {
+            if (v == null)
+                v = LayoutInflater.from(getContext()).inflate(R.layout.collection_members_list_item, parent, false);
+
+            JournalManager.Member member = getItem(position);
+
+            TextView tv = (TextView) v.findViewById(R.id.title);
+            tv.setText(member.getUser());
+            return v;
+        }
+    }
+
+    private class JournalMembersFetch extends AsyncTask<Void, Void, JournalMembersFetch.MembersResult> {
+        @Override
+        protected MembersResult doInBackground(Void... voids) {
+            try {
+                OkHttpClient httpClient = HttpClient.create(getContext(), account);
+                AccountSettings settings = new AccountSettings(getContext(), account);
+                JournalManager journalsManager = new JournalManager(httpClient, HttpUrl.get(settings.getUri()));
+
+                JournalManager.Journal journal = JournalManager.Journal.fakeWithUid(journalEntity.getUid());
+                return new MembersResult(journalsManager.listMembers(journal), null);
+            } catch (Exception e) {
+                return new MembersResult(null, e);
+            }
+        }
+
+        @Override
+        protected void onPostExecute(MembersResult result) {
+            if (result.throwable == null) {
+                MembersListAdapter listAdapter = new MembersListAdapter(getContext());
+                setListAdapter(listAdapter);
+
+                listAdapter.addAll(result.members);
+
+                emptyTextView.setText(R.string.collection_members_list_empty);
+            } else {
+                emptyTextView.setText(result.throwable.getLocalizedMessage());
+            }
+        }
+
+        @RequiredArgsConstructor
+        class MembersResult {
+            final List<JournalManager.Member> members;
+            final Throwable throwable;
+        }
+    }
+}

app/src/main/java/com/etesync/syncadapter/ui/RemoveMemberFragment.java

@@ -0,0 +1,116 @@
+package com.etesync.syncadapter.ui;
+
+import android.accounts.Account;
+import android.app.Dialog;
+import android.app.ProgressDialog;
+import android.content.DialogInterface;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.v4.app.DialogFragment;
+import android.support.v7.app.AlertDialog;
+
+import com.etesync.syncadapter.AccountSettings;
+import com.etesync.syncadapter.Constants;
+import com.etesync.syncadapter.HttpClient;
+import com.etesync.syncadapter.InvalidAccountException;
+import com.etesync.syncadapter.R;
+import com.etesync.syncadapter.journalmanager.Crypto;
+import com.etesync.syncadapter.journalmanager.JournalManager;
+import com.etesync.syncadapter.journalmanager.UserInfoManager;
+import com.etesync.syncadapter.model.CollectionInfo;
+
+import org.apache.commons.codec.Charsets;
+
+import lombok.RequiredArgsConstructor;
+import okhttp3.HttpUrl;
+import okhttp3.OkHttpClient;
+
+public class RemoveMemberFragment extends DialogFragment {
+    final static private String KEY_MEMBER = "memberEmail";
+    private AccountSettings settings;
+    private OkHttpClient httpClient;
+    private HttpUrl remote;
+    private CollectionInfo info;
+    private String memberEmail;
+
+    public static RemoveMemberFragment newInstance(Account account, CollectionInfo info, String email) {
+        RemoveMemberFragment frag = new RemoveMemberFragment();
+        Bundle args = new Bundle(1);
+        args.putParcelable(Constants.KEY_ACCOUNT, account);
+        args.putSerializable(Constants.KEY_COLLECTION_INFO, info);
+        args.putString(KEY_MEMBER, email);
+        frag.setArguments(args);
+        return frag;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        Account account = getArguments().getParcelable(Constants.KEY_ACCOUNT);
+        info = (CollectionInfo) getArguments().getSerializable(Constants.KEY_COLLECTION_INFO);
+        memberEmail = getArguments().getString(KEY_MEMBER);
+        try {
+            settings = new AccountSettings(getContext(), account);
+            httpClient = HttpClient.create(getContext(), account);
+        } catch (InvalidAccountException e) {
+            e.printStackTrace();
+        }
+        remote = HttpUrl.get(settings.getUri());
+
+        new MemberRemove().execute();
+    }
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        ProgressDialog progress = new ProgressDialog(getContext());
+        progress.setTitle(R.string.collection_members_removing);
+        progress.setMessage(getString(R.string.please_wait));
+        progress.setIndeterminate(true);
+        progress.setCanceledOnTouchOutside(false);
+        setCancelable(false);
+        return progress;
+    }
+
+    private class MemberRemove extends AsyncTask<Void, Void, MemberRemove.RemoveResult> {
+        @Override
+        protected RemoveResult doInBackground(Void... voids) {
+            try {
+                JournalManager journalsManager = new JournalManager(httpClient, remote);
+                JournalManager.Journal journal = JournalManager.Journal.fakeWithUid(info.uid);
+
+                JournalManager.Member member = new JournalManager.Member(memberEmail, "placeholder".getBytes(Charsets.UTF_8));
+                journalsManager.deleteMember(journal, member);
+
+                return new RemoveResult(null);
+            } catch (Exception e) {
+                return new RemoveResult(e);
+            }
+        }
+
+        @Override
+        protected void onPostExecute(RemoveResult result) {
+            if (result.throwable == null) {
+                ((Refreshable) getActivity()).refresh();
+            } else {
+                new AlertDialog.Builder(getActivity())
+                        .setIcon(R.drawable.ic_error_dark)
+                        .setTitle(R.string.collection_members_remove_error)
+                        .setMessage(result.throwable.getMessage())
+                        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+
+                            }
+                        }).show();
+            }
+            dismiss();
+        }
+
+        @RequiredArgsConstructor
+        class RemoveResult {
+            final Throwable throwable;
+        }
+    }
+}

app/src/main/java/com/etesync/syncadapter/ui/ViewCollectionActivity.java

@@ -168,6 +168,24 @@ public class ViewCollectionActivity extends AppCompatActivity implements Refresh
         startActivity(ImportActivity.newIntent(ViewCollectionActivity.this, account, info));
     }
 
+    public void onManageMembers(MenuItem item) {
+        if (isOwner) {
+            startActivity(CollectionMembersActivity.newIntent(this, account, info));
+        } else {
+            AlertDialog dialog = new AlertDialog.Builder(this)
+                    .setIcon(R.drawable.ic_info_dark)
+                    .setTitle(R.string.not_allowed_title)
+                    .setMessage(getString(R.string.members_owner_only, journalEntity.getOwner()))
+                    .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+
+                        }
+                    }).create();
+            dialog.show();
+        }
+    }
+
     private class LoadCountTask extends AsyncTask<Void, Void, Long> {
         private int entryCount;
 

app/src/main/res/drawable/ic_account_add_dark.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0"
+        android:alpha="0.54" >
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M15,14C12.33,14 7,15.33 7,18V20H23V18C23,15.33 17.67,14 15,14M6,10V7H4V10H1V12H4V15H6V12H9V10M15,12A4,4 0 0,0 19,8A4,4 0 0,0 15,4A4,4 0 0,0 11,8A4,4 0 0,0 15,12Z" />
+</vector>

app/src/main/res/drawable/ic_members_dark.xml

@@ -0,0 +1,5 @@
+<vector android:alpha="0.54" android:height="24dp"
+    android:viewportHeight="24.0" android:viewportWidth="24.0"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M16,13C15.71,13 15.38,13 15.03,13.05C16.19,13.89 17,15 17,16.5V19H23V16.5C23,14.17 18.33,13 16,13M8,13C5.67,13 1,14.17 1,16.5V19H15V16.5C15,14.17 10.33,13 8,13M8,11A3,3 0 0,0 11,8A3,3 0 0,0 8,5A3,3 0 0,0 5,8A3,3 0 0,0 8,11M16,11A3,3 0 0,0 19,8A3,3 0 0,0 16,5A3,3 0 0,0 13,8A3,3 0 0,0 16,11Z"/>
+</vector>

app/src/main/res/layout/collection_header.xml

@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="vertical">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal">
+
+        <TextView
+            android:id="@+id/display_name"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical"
+            android:layout_weight="1"
+            android:hint="@string/create_calendar_display_name_hint"
+            android:textAppearance="?android:attr/textAppearanceMedium" />
+
+        <View
+            android:id="@+id/color"
+            android:layout_width="32dp"
+            android:layout_height="32dp"
+            android:layout_marginLeft="16dp"
+            android:background="@color/orangeA700" />
+
+    </LinearLayout>
+
+    <TextView
+        android:id="@+id/description"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp" />
+</LinearLayout>

app/src/main/res/layout/collection_members_list.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <ListView
+        android:id="@id/android:list"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent" />
+
+    <TextView
+        android:id="@id/android:empty"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_margin="16dp"
+        android:gravity="center"
+        android:text="@string/collection_members_list_loading"
+        android:textAppearance="@style/TextAppearance.AppCompat.Large" />
+</LinearLayout>

app/src/main/res/layout/collection_members_list_item.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:padding="8dp"
+    android:gravity="center_vertical">
+
+    <LinearLayout android:layout_width="0dp"
+        android:layout_weight="1"
+        android:layout_height="wrap_content"
+        android:layout_marginLeft="8dp"
+        android:orientation="vertical">
+
+        <TextView
+            android:id="@+id/title"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:textAppearance="?android:attr/textAppearanceMedium"
+            tools:text="Title"/>
+
+    </LinearLayout>
+</LinearLayout>

app/src/main/res/layout/view_collection_activity.xml

@@ -5,42 +5,11 @@
               android:layout_height="match_parent"
               android:orientation="vertical">
 
-    <LinearLayout
+    <include
+        layout="@layout/collection_header"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:orientation="vertical"
-        android:padding="@dimen/activity_margin">
-
-
-        <LinearLayout
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content"
-            android:orientation="horizontal">
-
-            <TextView
-                android:id="@+id/display_name"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:layout_gravity="center_vertical"
-                android:layout_weight="1"
-                android:hint="@string/create_calendar_display_name_hint"
-                android:textAppearance="?android:attr/textAppearanceMedium"/>
-
-            <View
-                android:id="@+id/color"
-                android:layout_width="32dp"
-                android:layout_height="32dp"
-                android:layout_marginLeft="16dp"
-                android:background="@color/orangeA700"/>
-
-        </LinearLayout>
-
-        <TextView
-            android:id="@+id/description"
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content"
-            android:layout_marginBottom="16dp"/>
-    </LinearLayout>
+        android:layout_margin="@dimen/activity_margin" />
 
     <TextView
         android:layout_width="match_parent"

app/src/main/res/layout/view_collection_members.xml

@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <include
+        layout="@layout/collection_header"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_margin="@dimen/activity_margin" />
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:padding="@dimen/activity_margin">
+
+        <ProgressBar
+            android:id="@+id/progressBar"
+            android:layout_width="wrap_content"
+            android:layout_height="match_parent"
+            android:layout_gravity="right" />
+    </LinearLayout>
+
+    <LinearLayout
+        android:id="@+id/add_member"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_margin="@dimen/activity_margin"
+        android:onClick="onAddMemberClicked"
+        android:orientation="horizontal">
+
+        <TextView
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:layout_weight="1"
+            android:text="@string/collection_members_add"
+            android:textAppearance="?android:attr/textAppearanceMedium" />
+
+        <ImageView
+            android:id="@+id/icon"
+            android:layout_width="32dp"
+            android:layout_height="32dp"
+            android:layout_gravity="center"
+            android:src="@drawable/ic_account_add_dark" />
+
+    </LinearLayout>
+
+    <LinearLayout
+        android:id="@+id/list_entries_container"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1"
+        android:orientation="vertical">
+
+    </LinearLayout>
+
+</LinearLayout>

app/src/main/res/menu/activity_view_collection.xml

@@ -15,6 +15,11 @@
         android:onClick="onEditCollection"
         app:showAsAction="always" />
 
+    <item android:title="@string/view_collection_members"
+        android:icon="@drawable/ic_members_dark"
+        android:onClick="onManageMembers"
+        app:showAsAction="ifRoom"/>
+
     <item android:title="@string/view_collection_import"
         android:onClick="onImport"
         app:showAsAction="never"/>

app/src/main/res/values/strings.xml

@@ -103,6 +103,20 @@
     <!-- ViewCollection -->
     <string name="change_journal_title">Change Journal</string>
     <string name="account_showcase_import">In order to import contacts and calendars into EteSync, you need to click on the menu, and choose \"Import\".</string>
+    <string name="members_owner_only">Only the owner of this collection (%s) is allowed to view its members.</string>
+
+    <!-- CollectionMembers -->
+    <string name="collection_members_title">Members</string>
+    <string name="collection_members_list_loading">Loading members...</string>
+    <string name="collection_members_list_empty">No members</string>
+    <string name="collection_members_add">Add member</string>
+    <string name="collection_members_add_error">Error adding member</string>
+    <string name="collection_members_adding">Adding member</string>
+    <string name="trust_fingerprint_title">Trust fingerprint?</string>
+    <string name="collection_members_removing">Removing member</string>
+    <string name="collection_members_remove_error">Error removing member</string>
+    <string name="collection_members_remove_title">Remove member</string>
+    <string name="collection_members_remove">Would you like to revoke %s\'s access?\nPlease be advised that a malicious user would potentially be able to retain access to encryption keys. Please refer to the FAQ for more information.</string>
 
     <!-- PermissionsActivity -->
     <string name="permissions_title">EteSync permissions</string>
@@ -215,6 +229,7 @@
     <string name="create_collection_description">Description (optional):</string>
     <string name="view_collection_edit">Edit</string>
     <string name="view_collection_import">Import</string>
+    <string name="view_collection_members">Manage Members</string>
     <string name="create_collection_create">Save</string>
     <string name="delete_collection">Delete</string>
     <string name="delete_collection_confirm_title">Are you sure?</string>