root/remoting/android/java/src/org/chromium/chromoting/Chromoting.java

DEFINITIONS

1. showNoAccountsDialog
2. setHostListProgressVisible
3. onCreate
4. onStart
5. onDestroy
6. onConfigurationChanged
7. onCreateOptionsMenu
8. onOptionsItemSelected
9. onClick
10. connectToHost
11. refreshHostList
12. run
13. onNavigationItemSelected
14. onHostListReceived
15. onError
16. updateUi
17. onConnectionState

// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package org.chromium.chromoting;

import android.accounts.Account;
import android.accounts.AccountManager;
import android.accounts.AccountManagerCallback;
import android.accounts.AccountManagerFuture;
import android.accounts.AuthenticatorException;
import android.accounts.OperationCanceledException;
import android.app.ActionBar;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.provider.Settings;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import org.chromium.chromoting.jni.JniInterface;

import java.io.IOException;
import java.util.Arrays;

/**
 * The user interface for querying and displaying a user's host list from the directory server. It
 * also requests and renews authentication tokens using the system account manager.
 */
public class Chromoting extends Activity implements JniInterface.ConnectionListener,
        AccountManagerCallback<Bundle>, ActionBar.OnNavigationListener, HostListLoader.Callback,
        View.OnClickListener {
    /** Only accounts of this type will be selectable for authentication. */
    private static final String ACCOUNT_TYPE = "com.google";

    /** Scopes at which the authentication token we request will be valid. */
    private static final String TOKEN_SCOPE = "oauth2:https://www.googleapis.com/auth/chromoting " +
            "https://www.googleapis.com/auth/googletalk";

    /** Web page to be displayed in the Help screen when launched from this activity. */
    private static final String HELP_URL =
            "http://support.google.com/chrome/?p=mobile_crd_hostslist";

    /** Web page to be displayed when user triggers the hyperlink for setting up hosts. */
    private static final String HOST_SETUP_URL =
            "https://support.google.com/chrome/answer/1649523";

    /** User's account details. */
    private Account mAccount;

    /** List of accounts on the system. */
    private Account[] mAccounts;

    /** SpinnerAdapter used in the action bar for selecting accounts. */
    private AccountsAdapter mAccountsAdapter;

    /** Account auth token. */
    private String mToken;

    /** Helper for fetching the host list. */
    private HostListLoader mHostListLoader;

    /** List of hosts. */
    private HostInfo[] mHosts = new HostInfo[0];

    /** Refresh button. */
    private MenuItem mRefreshButton;

    /** Host list as it appears to the user. */
    private ListView mHostListView;

    /** Progress view shown instead of the host list when the host list is loading. */
    private View mProgressView;

    /** Dialog for reporting connection progress. */
    private ProgressDialog mProgressIndicator;

    /**
     * This is set when receiving an authentication error from the HostListLoader. If that occurs,
     * this flag is set and a fresh authentication token is fetched from the AccountsService, and
     * used to request the host list a second time.
     */
    boolean mTriedNewAuthToken;

    /** Shows a warning explaining that a Google account is required, then closes the activity. */
    private void showNoAccountsDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setMessage(R.string.noaccounts_message);
        builder.setPositiveButton(R.string.noaccounts_add_account,
                new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int id) {
                        Intent intent = new Intent(Settings.ACTION_ADD_ACCOUNT);
                        intent.putExtra(Settings.EXTRA_ACCOUNT_TYPES,
                                new String[] { ACCOUNT_TYPE });
                        if (intent.resolveActivity(getPackageManager()) != null) {
                            startActivity(intent);
                        }
                        finish();
                    }
                });
        builder.setNegativeButton(R.string.close, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int id) {
                    finish();
                }
            });
        builder.setOnCancelListener(new DialogInterface.OnCancelListener() {
                @Override
                public void onCancel(DialogInterface dialog) {
                    finish();
                }
            });

        AlertDialog dialog = builder.create();
        dialog.show();
    }

    /** Shows or hides the progress indicator for loading the host list. */
    private void setHostListProgressVisible(boolean visible) {
        mHostListView.setVisibility(visible ? View.GONE : View.VISIBLE);
        mProgressView.setVisibility(visible ? View.VISIBLE : View.GONE);

        // Hiding the host-list does not automatically hide the empty view, so do that here.
        if (visible) {
            mHostListView.getEmptyView().setVisibility(View.GONE);
        }
    }

    /**
     * Called when the activity is first created. Loads the native library and requests an
     * authentication token from the system.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mTriedNewAuthToken = false;
        mHostListLoader = new HostListLoader();

        // Get ahold of our view widgets.
        mHostListView = (ListView)findViewById(R.id.hostList_chooser);
        mHostListView.setEmptyView(findViewById(R.id.hostList_empty));
        mProgressView = findViewById(R.id.hostList_progress);

        findViewById(R.id.host_setup_link_android).setOnClickListener(this);

        // Bring native components online.
        JniInterface.loadLibrary(this);
    }

    /**
     * Called when the activity becomes visible. This happens on initial launch and whenever the
     * user switches to the activity, for example, by using the window-switcher or when coming from
     * the device's lock screen.
     */
    @Override
    public void onStart() {
        super.onStart();

        mAccounts = AccountManager.get(this).getAccountsByType(ACCOUNT_TYPE);
        if (mAccounts.length == 0) {
            showNoAccountsDialog();
            return;
        }

        SharedPreferences prefs = getPreferences(MODE_PRIVATE);
        int index = -1;
        if (prefs.contains("account_name") && prefs.contains("account_type")) {
            mAccount = new Account(prefs.getString("account_name", null),
                    prefs.getString("account_type", null));
            index = Arrays.asList(mAccounts).indexOf(mAccount);
        }
        if (index == -1) {
            // Preference not loaded, or does not correspond to a valid account, so just pick the
            // first account arbitrarily.
            index = 0;
            mAccount = mAccounts[0];
        }

        if (mAccounts.length == 1) {
            getActionBar().setDisplayShowTitleEnabled(true);
            getActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
            getActionBar().setTitle(R.string.mode_me2me);
            getActionBar().setSubtitle(mAccount.name);
        } else {
            mAccountsAdapter = new AccountsAdapter(this, mAccounts);
            getActionBar().setDisplayShowTitleEnabled(false);
            getActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
            getActionBar().setListNavigationCallbacks(mAccountsAdapter, this);
            getActionBar().setSelectedNavigationItem(index);
        }

        refreshHostList();
    }

    /** Called when the activity is finally finished. */
    @Override
    public void onDestroy() {
        super.onDestroy();
        JniInterface.disconnectFromHost();
    }

    /** Called when the display is rotated (as registered in the manifest). */
    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);

        // Reload the spinner resources, since the font sizes are dependent on the screen
        // orientation.
        if (mAccounts.length != 1) {
            mAccountsAdapter.notifyDataSetChanged();
        }
    }

    /** Called to initialize the action bar. */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.chromoting_actionbar, menu);
        mRefreshButton = menu.findItem(R.id.actionbar_directoryrefresh);

        if (mAccount == null) {
            // If there is no account, don't allow the user to refresh the listing.
            mRefreshButton.setEnabled(false);
        }

        return super.onCreateOptionsMenu(menu);
    }

    /** Called whenever an action bar button is pressed. */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.actionbar_directoryrefresh:
                refreshHostList();
                return true;

            case R.id.actionbar_help:
                HelpActivity.launch(this, HELP_URL);
                return true;

            default:
                return super.onOptionsItemSelected(item);
        }
    }

    /** Called when the user touches hyperlinked text. */
    @Override
    public void onClick(View view) {
        HelpActivity.launch(this, HOST_SETUP_URL);
    }

    /** Called when the user taps on a host entry. */
    public void connectToHost(HostInfo host) {
        mProgressIndicator = ProgressDialog.show(this,
              host.name, getString(R.string.footer_connecting), true, true,
              new DialogInterface.OnCancelListener() {
                  @Override
                  public void onCancel(DialogInterface dialog) {
                      JniInterface.disconnectFromHost();
                  }
              });
        SessionConnector connector = new SessionConnector(this, this, mHostListLoader);
        connector.connectToHost(mAccount.name, mToken, host);
    }

    private void refreshHostList() {
        mTriedNewAuthToken = false;
        setHostListProgressVisible(true);

        // The refresh button simply makes use of the currently-chosen account.
        AccountManager.get(this).getAuthToken(mAccount, TOKEN_SCOPE, null, this, this, null);
    }

    @Override
    public void run(AccountManagerFuture<Bundle> future) {
        Log.i("auth", "User finished with auth dialogs");
        Bundle result = null;
        String explanation = null;
        try {
            // Here comes our auth token from the Android system.
            result = future.getResult();
            String authToken = result.getString(AccountManager.KEY_AUTHTOKEN);
            Log.i("auth", "Received an auth token from system");

            mToken = authToken;

            mHostListLoader.retrieveHostList(authToken, this);
        } catch (OperationCanceledException ex) {
            // User canceled authentication. No need to report an error.
        } catch (AuthenticatorException ex) {
            explanation = getString(R.string.error_unexpected);
        } catch (IOException ex) {
            explanation = getString(R.string.error_network_error);
        }

        if (result == null) {
            if (explanation != null) {
                Toast.makeText(this, explanation, Toast.LENGTH_LONG).show();
            }
            return;
        }

        String authToken = result.getString(AccountManager.KEY_AUTHTOKEN);
        Log.i("auth", "Received an auth token from system");

        mToken = authToken;

        mHostListLoader.retrieveHostList(authToken, this);
    }

    @Override
    public boolean onNavigationItemSelected(int itemPosition, long itemId) {
        mAccount = mAccounts[itemPosition];

        getPreferences(MODE_PRIVATE).edit().putString("account_name", mAccount.name).
                    putString("account_type", mAccount.type).apply();

        // The current host list is no longer valid for the new account, so clear the list.
        mHosts = new HostInfo[0];
        updateUi();
        refreshHostList();
        return true;
    }

    @Override
    public void onHostListReceived(HostInfo[] hosts) {
        // Store a copy of the array, so that it can't be mutated by the HostListLoader. HostInfo
        // is an immutable type, so a shallow copy of the array is sufficient here.
        mHosts = Arrays.copyOf(hosts, hosts.length);
        setHostListProgressVisible(false);
        updateUi();
    }

    @Override
    public void onError(HostListLoader.Error error) {
        String explanation = null;
        switch (error) {
            case AUTH_FAILED:
                break;
            case NETWORK_ERROR:
                explanation = getString(R.string.error_network_error);
                break;
            case UNEXPECTED_RESPONSE:
            case SERVICE_UNAVAILABLE:
            case UNKNOWN:
                explanation = getString(R.string.error_unexpected);
                break;
            default:
                // Unreachable.
                return;
        }

        if (explanation != null) {
            Toast.makeText(this, explanation, Toast.LENGTH_LONG).show();
            setHostListProgressVisible(false);
            return;
        }

        // This is the AUTH_FAILED case.

        if (!mTriedNewAuthToken) {
            // This was our first connection attempt.

            AccountManager authenticator = AccountManager.get(this);
            mTriedNewAuthToken = true;

            Log.w("auth", "Requesting renewal of rejected auth token");
            authenticator.invalidateAuthToken(mAccount.type, mToken);
            mToken = null;
            authenticator.getAuthToken(mAccount, TOKEN_SCOPE, null, this, this, null);

            // We're not in an error state *yet*.
            return;
        } else {
            // Authentication truly failed.
            Log.e("auth", "Fresh auth token was also rejected");
            explanation = getString(R.string.error_authentication_failed);
            Toast.makeText(this, explanation, Toast.LENGTH_LONG).show();
            setHostListProgressVisible(false);
        }
    }

    /**
     * Updates the infotext and host list display.
     */
    private void updateUi() {
        mRefreshButton.setEnabled(mAccount != null);

        ArrayAdapter<HostInfo> displayer = new HostListAdapter(this, R.layout.host, mHosts);
        Log.i("hostlist", "About to populate host list display");
        mHostListView.setAdapter(displayer);
    }

    @Override
    public void onConnectionState(JniInterface.ConnectionListener.State state,
            JniInterface.ConnectionListener.Error error) {
        boolean dismissProgress = false;
        switch (state) {
            case INITIALIZING:
            case CONNECTING:
            case AUTHENTICATED:
                // The connection is still being established.
                break;

            case CONNECTED:
                dismissProgress = true;
                // Display the remote desktop.
                startActivityForResult(new Intent(this, Desktop.class), 0);
                break;

            case FAILED:
                dismissProgress = true;
                Toast.makeText(this, getString(error.message()), Toast.LENGTH_LONG).show();
                // Close the Desktop view, if it is currently running.
                finishActivity(0);
                break;

            case CLOSED:
                // No need to show toast in this case. Either the connection will have failed
                // because of an error, which will trigger toast already. Or the disconnection will
                // have been initiated by the user.
                dismissProgress = true;
                finishActivity(0);
                break;

            default:
                // Unreachable, but required by Google Java style and findbugs.
                assert false : "Unreached";
        }

        if (dismissProgress && mProgressIndicator != null) {
            mProgressIndicator.dismiss();
            mProgressIndicator = null;
        }
    }
}