Android技术精髓-理解Context [源码]

Android技术精髓-理解Context [源码]

Context：

Context类是一个抽象类，定义应用程序环境的全局信息，它允许访问应用程序特定的资源和类，以及最新的电话应用程序级别的操作，例如： launching activities, broadcasting and receiving intents 等操作！

图1：Context定义的抽象方法以及全局变量

举个例子：

Context抽象类定义了StartActivity的方法，而并非是我们所想的在Activity中定义。

abstract void

startActivities(Intent[] intents, Bundle options)

Launch multiple new activities.

abstract voidstartActivities(Intent[] intents)

Same as startActivities(Intent[], Bundle) with no options specified.

abstract voidstartActivity(Intent intent)

Same as startActivity(Intent, Bundle) with no options specified.

abstract voidstartActivity(Intent intent, Bundle options)

Launch a new activity.

在Android源代码中此抽象方法定义如下：

  public abstract void startActivity(Intent intent);

  public abstract boolean stopService(Intent service);      public abstract boolean bindService(Intent service, ServiceConnection conn,            int flags);  public abstract void unbindService(ServiceConnection conn);

总结下：

1、它描述的是一个应用程序环境的信息，即上下文。

2、该类是一个抽象(abstract class)类，Android提供了该抽象类的具体实现类(后面我们会讲到是ContextIml类)。

3、通过它我们可以获取应用程序的资源和类，也包括一些应用级别操作，例如：启动一个Activity，发送广播，接受Intent信息 等。

Context相关类的继承关系

、

ContextIml.java类：

该Context类的实现类为ContextIml，该类实现了Context类的功能。请注意，该函数的大部分功能都是直接调用其属性mPackageInfo去完成

源码：

/** * Common implementation of Context API, which provides the base * context object for Activity and other application components. */class ContextImpl extends Context {    private final static String TAG = "ApplicationContext";    private final static boolean DEBUG = false;    private final static boolean DEBUG_ICONS = false;

//以下选择部分function实现源码贴出

 @Override    public PackageManager getPackageManager() {        if (mPackageManager != null) {            return mPackageManager;        }        IPackageManager pm = ActivityThread.getPackageManager();        if (pm != null) {            // Doesn't matter if we make more than one instance.            return (mPackageManager = new ApplicationPackageManager(this, pm));        }        return null;    }

  @Override    public void setTheme(int resid) {        mThemeResource = resid;    }        @Override    public Resources.Theme getTheme() {        if (mTheme == null) {            if (mThemeResource == 0) {                mThemeResource = com.android.internal.R.style.Theme;            }            mTheme = mResources.newTheme();            mTheme.applyStyle(mThemeResource, true);        }        return mTheme;    }

  private static File makeBackupFile(File prefsFile) {        return new File(prefsFile.getPath() + ".bak");    }    public File getSharedPrefsFile(String name) {        return makeFilename(getPreferencesDir(), name + ".xml");    }    @Override    public SharedPreferences getSharedPreferences(String name, int mode) {        SharedPreferencesImpl sp;        File prefsFile;        boolean needInitialLoad = false;        synchronized (sSharedPrefs) {            sp = sSharedPrefs.get(name);            if (sp != null && !sp.hasFileChangedUnexpectedly()) {                return sp;            }            prefsFile = getSharedPrefsFile(name);            if (sp == null) {                sp = new SharedPreferencesImpl(prefsFile, mode, null);                sSharedPrefs.put(name, sp);                needInitialLoad = true;            }        }        synchronized (sp) {            if (needInitialLoad && sp.isLoaded()) {                // lost the race to load; another thread handled it                return sp;            }            File backup = makeBackupFile(prefsFile);            if (backup.exists()) {                prefsFile.delete();                backup.renameTo(prefsFile);            }            // Debugging            if (prefsFile.exists() && !prefsFile.canRead()) {                Log.w(TAG, "Attempt to read preferences file " + prefsFile + " without permission");            }            Map map = null;            FileStatus stat = new FileStatus();            if (FileUtils.getFileStatus(prefsFile.getPath(), stat) && prefsFile.canRead()) {                try {                    FileInputStream str = new FileInputStream(prefsFile);                    map = XmlUtils.readMapXml(str);                    str.close();                } catch (org.xmlpull.v1.XmlPullParserException e) {                    Log.w(TAG, "getSharedPreferences", e);                } catch (FileNotFoundException e) {                    Log.w(TAG, "getSharedPreferences", e);                } catch (IOException e) {                    Log.w(TAG, "getSharedPreferences", e);                }            }            sp.replace(map, stat);        }        return sp;    }    private File getPreferencesDir() {        synchronized (mSync) {            if (mPreferencesDir == null) {                mPreferencesDir = new File(getDataDirFile(), "shared_prefs");            }            return mPreferencesDir;        }    }    @Override    public FileInputStream openFileInput(String name)        throws FileNotFoundException {        File f = makeFilename(getFilesDir(), name);        return new FileInputStream(f);    }    @Override    public FileOutputStream openFileOutput(String name, int mode)        throws FileNotFoundException {        final boolean append = (mode&MODE_APPEND) != 0;        File f = makeFilename(getFilesDir(), name);        try {            FileOutputStream fos = new FileOutputStream(f, append);            setFilePermissionsFromMode(f.getPath(), mode, 0);            return fos;        } catch (FileNotFoundException e) {        }        File parent = f.getParentFile();        parent.mkdir();        FileUtils.setPermissions(            parent.getPath(),            FileUtils.S_IRWXU|FileUtils.S_IRWXG|FileUtils.S_IXOTH,            -1, -1);        FileOutputStream fos = new FileOutputStream(f, append);        setFilePermissionsFromMode(f.getPath(), mode, 0);        return fos;    }    @Override    public boolean deleteFile(String name) {        File f = makeFilename(getFilesDir(), name);        return f.delete();    }  @Override    public File getFilesDir() {        synchronized (mSync) {            if (mFilesDir == null) {                mFilesDir = new File(getDataDirFile(), "files");            }            if (!mFilesDir.exists()) {                if(!mFilesDir.mkdirs()) {                    Log.w(TAG, "Unable to create files directory");                    return null;                }                FileUtils.setPermissions(                        mFilesDir.getPath(),                        FileUtils.S_IRWXU|FileUtils.S_IRWXG|FileUtils.S_IXOTH,                        -1, -1);            }            return mFilesDir;        }    }

 @Override    public void startActivity(Intent intent) {        if ((intent.getFlags()&Intent.FLAG_ACTIVITY_NEW_TASK) == 0) {            throw new AndroidRuntimeException(                    "Calling startActivity() from outside of an Activity "                    + " context requires the FLAG_ACTIVITY_NEW_TASK flag."                    + " Is this really what you want?");        }        mMainThread.getInstrumentation().execStartActivity(            getOuterContext(), mMainThread.getApplicationThread(), null, null, intent, -1);    }

    @Override    public void sendBroadcast(Intent intent, String receiverPermission) {        String resolvedType = intent.resolveTypeIfNeeded(getContentResolver());        try {            ActivityManagerNative.getDefault().broadcastIntent(                mMainThread.getApplicationThread(), intent, resolvedType, null,                Activity.RESULT_OK, null, null, receiverPermission, false, false);        } catch (RemoteException e) {        }    }

   @Override    public ComponentName startService(Intent service) {        try {            ComponentName cn = ActivityManagerNative.getDefault().startService(                mMainThread.getApplicationThread(), service,                service.resolveTypeIfNeeded(getContentResolver()));            if (cn != null && cn.getPackageName().equals("!")) {                throw new SecurityException(                        "Not allowed to start service " + service                        + " without permission " + cn.getClassName());            }            return cn;        } catch (RemoteException e) {            return null;        }    }    @Override    public boolean stopService(Intent service) {        try {            int res = ActivityManagerNative.getDefault().stopService(                mMainThread.getApplicationThread(), service,                service.resolveTypeIfNeeded(getContentResolver()));            if (res < 0) {                throw new SecurityException(                        "Not allowed to stop service " + service);            }            return res != 0;        } catch (RemoteException e) {            return false;        }    }    @Override    public boolean bindService(Intent service, ServiceConnection conn,            int flags) {        IServiceConnection sd;        if (mPackageInfo != null) {            sd = mPackageInfo.getServiceDispatcher(conn, getOuterContext(),                    mMainThread.getHandler(), flags);        } else {            throw new RuntimeException("Not supported in system context");        }        try {            int res = ActivityManagerNative.getDefault().bindService(                mMainThread.getApplicationThread(), getActivityToken(),                service, service.resolveTypeIfNeeded(getContentResolver()),                sd, flags);            if (res < 0) {                throw new SecurityException(                        "Not allowed to bind to service " + service);            }            return res != 0;        } catch (RemoteException e) {            return false;        }    }    @Override    public void unbindService(ServiceConnection conn) {        if (mPackageInfo != null) {            IServiceConnection sd = mPackageInfo.forgetServiceDispatcher(                    getOuterContext(), conn);            try {                ActivityManagerNative.getDefault().unbindService(sd);            } catch (RemoteException e) {            }        } else {            throw new RuntimeException("Not supported in system context");        }    }    @Override    public Object getSystemService(String name) {        if (WINDOW_SERVICE.equals(name)) {            return WindowManagerImpl.getDefault();        } else if (LAYOUT_INFLATER_SERVICE.equals(name)) {            synchronized (mSync) {                LayoutInflater inflater = mLayoutInflater;                if (inflater != null) {                    return inflater;                }                mLayoutInflater = inflater =                    PolicyManager.makeNewLayoutInflater(getOuterContext());                return inflater;            }        } else if (ACTIVITY_SERVICE.equals(name)) {            return getActivityManager();        } else if (INPUT_METHOD_SERVICE.equals(name)) {            return InputMethodManager.getInstance(this);        } else if (ALARM_SERVICE.equals(name)) {            return getAlarmManager();        } else if (ACCOUNT_SERVICE.equals(name)) {            return getAccountManager();        } else if (POWER_SERVICE.equals(name)) {            return getPowerManager();        } else if (CONNECTIVITY_SERVICE.equals(name)) {            return getConnectivityManager();        } else if (THROTTLE_SERVICE.equals(name)) {            return getThrottleManager();        } else if (WIFI_SERVICE.equals(name)) {            return getWifiManager();        } else if (NOTIFICATION_SERVICE.equals(name)) {            return getNotificationManager();        } else if (KEYGUARD_SERVICE.equals(name)) {            return new KeyguardManager();        } else if (ACCESSIBILITY_SERVICE.equals(name)) {            return AccessibilityManager.getInstance(this);        } else if (LOCATION_SERVICE.equals(name)) {            return getLocationManager();        } else if (SEARCH_SERVICE.equals(name)) {            return getSearchManager();        } else if (SENSOR_SERVICE.equals(name)) {            return getSensorManager();        } else if (STORAGE_SERVICE.equals(name)) {            return getStorageManager();        } else if (VIBRATOR_SERVICE.equals(name)) {            return getVibrator();        } else if (STATUS_BAR_SERVICE.equals(name)) {            synchronized (mSync) {                if (mStatusBarManager == null) {                    mStatusBarManager = new StatusBarManager(getOuterContext());                }                return mStatusBarManager;            }        } else if (AUDIO_SERVICE.equals(name)) {            return getAudioManager();        } else if (TELEPHONY_SERVICE.equals(name)) {            return getTelephonyManager();        } else if (CLIPBOARD_SERVICE.equals(name)) {            return getClipboardManager();        } else if (WALLPAPER_SERVICE.equals(name)) {            return getWallpaperManager();        } else if (DROPBOX_SERVICE.equals(name)) {            return getDropBoxManager();        } else if (DEVICE_POLICY_SERVICE.equals(name)) {            return getDevicePolicyManager();        } else if (UI_MODE_SERVICE.equals(name)) {            return getUiModeManager();        } else if (DOWNLOAD_SERVICE.equals(name)) {            return getDownloadManager();        } else if (NFC_SERVICE.equals(name)) {            return getNfcManager();        }        return null;    }

ContextWrapper类 ：

该类只是对Context类的一种包装，该类的构造函数包含了一个真正的Context引用，即ContextIml对象

源码：

public class ContextWrapper extends Context {    Context mBase;    public ContextWrapper(Context base) {        mBase = base;    }        /**     * Set the base context for this ContextWrapper.  All calls will then be     * delegated to the base context.  Throws     * IllegalStateException if a base context has already been set.     *      * @param base The new base context for this wrapper.     */    protected void attachBaseContext(Context base) {        if (mBase != null) {            throw new IllegalStateException("Base context already set");        }        mBase = base;    }    /**     * @return the base context as set by the constructor or setBaseContext     */    public Context getBaseContext() {        return mBase;    }    @Override    public AssetManager getAssets() {        return mBase.getAssets();    }    @Override    public Resources getResources()    {        return mBase.getResources();    }    @Override    public PackageManager getPackageManager() {        return mBase.getPackageManager();    }    @Override    public ContentResolver getContentResolver() {        return mBase.getContentResolver();    }    @Override    public Looper getMainLooper() {        return mBase.getMainLooper();    }        @Override    public Context getApplicationContext() {        return mBase.getApplicationContext();    }        @Override    public void setTheme(int resid) {        mBase.setTheme(resid);    }    @Override    public Resources.Theme getTheme() {        return mBase.getTheme();    }    @Override    public ClassLoader getClassLoader() {        return mBase.getClassLoader();    }    @Override    public String getPackageName() {        return mBase.getPackageName();    }    @Override    public ApplicationInfo getApplicationInfo() {        return mBase.getApplicationInfo();    }        @Override    public String getPackageResourcePath() {        return mBase.getPackageResourcePath();    }    @Override    public String getPackageCodePath() {        return mBase.getPackageCodePath();    }    /** @hide */    @Override    public File getSharedPrefsFile(String name) {        return mBase.getSharedPrefsFile(name);    }    @Override    public SharedPreferences getSharedPreferences(String name, int mode) {        return mBase.getSharedPreferences(name, mode);    }    @Override    public FileInputStream openFileInput(String name)        throws FileNotFoundException {        return mBase.openFileInput(name);    }    @Override    public FileOutputStream openFileOutput(String name, int mode)        throws FileNotFoundException {        return mBase.openFileOutput(name, mode);    }    @Override    public boolean deleteFile(String name) {        return mBase.deleteFile(name);

ContextThemeWrapper类 ：

该类内部包含了主题(Theme)相关的接口，即android:theme属性指定的。只有Activity需要主题，Service不需要主题， 所以Service直接继承于ContextWrapper类。

源码：

/** * A ContextWrapper that allows you to modify the theme from what is in the  * wrapped context.  */public class ContextThemeWrapper extends ContextWrapper {    private Context mBase;    private int mThemeResource;    private Resources.Theme mTheme;    private LayoutInflater mInflater;    public ContextThemeWrapper() {        super(null);    }        public ContextThemeWrapper(Context base, int themeres) {        super(base);        mBase = base;        mThemeResource = themeres;    }    @Override protected void attachBaseContext(Context newBase) {        super.attachBaseContext(newBase);        mBase = newBase;    }        @Override public void setTheme(int resid) {        mThemeResource = resid;        initializeTheme();    }        @Override public Resources.Theme getTheme() {        if (mTheme != null) {            return mTheme;        }        if (mThemeResource == 0) {            mThemeResource = com.android.internal.R.style.Theme;        }        initializeTheme();        return mTheme;    }    @Override public Object getSystemService(String name) {        if (LAYOUT_INFLATER_SERVICE.equals(name)) {            if (mInflater == null) {                mInflater = LayoutInflater.from(mBase).cloneInContext(this);            }            return mInflater;        }        return mBase.getSystemService(name);    }        /**     * Called by {@link #setTheme} and {@link #getTheme} to apply a theme     * resource to the current Theme object.  Can override to change the     * default (simple) behavior.  This method will not be called in multiple     * threads simultaneously.     *     * @param theme The Theme object being modified.     * @param resid The theme style resource being applied to <var>theme</var>.     * @param first Set to true if this is the first time a style is being     *              applied to <var>theme</var>.     */    protected void onApplyThemeResource(Resources.Theme theme, int resid, boolean first) {        theme.applyStyle(resid, true);    }    private void initializeTheme() {        final boolean first = mTheme == null;        if (first) {            mTheme = getResources().newTheme();            Resources.Theme theme = mBase.getTheme();            if (theme != null) {                mTheme.setTo(theme);            }        }        onApplyThemeResource(mTheme, mThemeResource, first);    }}

Activity类 、Service类 、Application类本质上都是Context子类。

Activity类源码（部分）：

public class Activity extends ContextThemeWrapper        implements LayoutInflater.Factory,        Window.Callback, KeyEvent.Callback,        OnCreateContextMenuListener, ComponentCallbacks {    private static final String TAG = "Activity";

  public static long getInstanceCount() {        return sInstanceCount;    }    /** Return the intent that started this activity. */    public Intent getIntent() {        return mIntent;    }    /**      * Change the intent returned by {@link #getIntent}.  This holds a      * reference to the given intent; it does not copy it.  Often used in      * conjunction with {@link #onNewIntent}.      *       * @param newIntent The new Intent object to return from getIntent      *      * @see #getIntent     * @see #onNewIntent     */     public void setIntent(Intent newIntent) {        mIntent = newIntent;    }    /** Return the application that owns this activity. */    public final Application getApplication() {        return mApplication;    }    /** Is this activity embedded inside of another activity? */    public final boolean isChild() {        return mParent != null;    }        /** Return the parent activity if this view is an embedded child. */    public final Activity getParent() {        return mParent;    }    /** Retrieve the window manager for showing custom windows. */    public WindowManager getWindowManager() {        return mWindowManager;    }      /**     * Called when the activity is starting.  This is where most initialization     * should go: calling {@link #setContentView(int)} to inflate the     * activity's UI, using {@link #findViewById} to programmatically interact     * with widgets in the UI, calling     * {@link #managedQuery(android.net.Uri , String[], String, String[], String)} to retrieve     * cursors for data being displayed, etc.     *      * <p>You can call {@link #finish} from within this function, in     * which case onDestroy() will be immediately called without any of the rest     * of the activity lifecycle ({@link #onStart}, {@link #onResume},     * {@link #onPause}, etc) executing.     *      * <p><em>Derived classes must call through to the super class's     * implementation of this method.  If they do not, an exception will be     * thrown.</em></p>     *      * @param savedInstanceState If the activity is being re-initialized after     *     previously being shut down then this Bundle contains the data it most     *     recently supplied in {@link #onSaveInstanceState}.  <b><i>Note: Otherwise it is null.</i></b>     *      * @see #onStart     * @see #onSaveInstanceState     * @see #onRestoreInstanceState     * @see #onPostCreate     */    protected void onCreate(Bundle savedInstanceState) {        mVisibleFromClient = !mWindow.getWindowStyle().getBoolean(                com.android.internal.R.styleable.Window_windowNoDisplay, false);        mCalled = true;    }

private Dialog createDialog(Integer dialogId, Bundle state, Bundle args) {        final Dialog dialog = onCreateDialog(dialogId, args);        if (dialog == null) {            return null;        }        dialog.dispatchOnCreate(state);        return dialog;    }

    protected void onDestroy() {        mCalled = true;        // dismiss any dialogs we are managing.        if (mManagedDialogs != null) {            final int numDialogs = mManagedDialogs.size();            for (int i = 0; i < numDialogs; i++) {                final ManagedDialog md = mManagedDialogs.valueAt(i);                if (md.mDialog.isShowing()) {                    md.mDialog.dismiss();                }            }            mManagedDialogs = null;        }        // close any cursors we are managing.        synchronized (mManagedCursors) {            int numCursors = mManagedCursors.size();            for (int i = 0; i < numCursors; i++) {                ManagedCursor c = mManagedCursors.get(i);                if (c != null) {                    c.mCursor.close();                }            }            mManagedCursors.clear();        }        // Close any open search dialog        if (mSearchManager != null) {            mSearchManager.stopSearch();        }    }

  /**     * Called when a key was pressed down and not handled by any of the views     * inside of the activity. So, for example, key presses while the cursor      * is inside a TextView will not trigger the event (unless it is a navigation     * to another object) because TextView handles its own key presses.     *      * <p>If the focused view didn't want this event, this method is called.     *     * <p>The default implementation takes care of {@link KeyEvent#KEYCODE_BACK}     * by calling {@link #onBackPressed()}, though the behavior varies based     * on the application compatibility mode: for     * {@link android.os.Build.VERSION_CODES#ECLAIR} or later applications,     * it will set up the dispatch to call {@link #onKeyUp} where the action     * will be performed; for earlier applications, it will perform the     * action immediately in on-down, as those versions of the platform     * behaved.     *      * <p>Other additional default key handling may be performed     * if configured with {@link #setDefaultKeyMode}.     *      * @return Return <code>true</code> to prevent this event from being propagated     * further, or <code>false</code> to indicate that you have not handled      * this event and it should continue to be propagated.     * @see #onKeyUp     * @see android.view.KeyEvent     */    public boolean onKeyDown(int keyCode, KeyEvent event)  {        if (keyCode == KeyEvent.KEYCODE_BACK) {            if (getApplicationInfo().targetSdkVersion                    >= Build.VERSION_CODES.ECLAIR) {                event.startTracking();            } else {                onBackPressed();            }            return true;        }                if (mDefaultKeyMode == DEFAULT_KEYS_DISABLE) {            return false;        } else if (mDefaultKeyMode == DEFAULT_KEYS_SHORTCUT) {            if (getWindow().performPanelShortcut(Window.FEATURE_OPTIONS_PANEL,                     keyCode, event, Menu.FLAG_ALWAYS_PERFORM_CLOSE)) {                return true;            }            return false;        } else {            // Common code for DEFAULT_KEYS_DIALER & DEFAULT_KEYS_SEARCH_*            boolean clearSpannable = false;            boolean handled;            if ((event.getRepeatCount() != 0) || event.isSystem()) {                clearSpannable = true;                handled = false;            } else {                handled = TextKeyListener.getInstance().onKeyDown(                        null, mDefaultKeySsb, keyCode, event);                if (handled && mDefaultKeySsb.length() > 0) {                    // something useable has been typed - dispatch it now.                    final String str = mDefaultKeySsb.toString();                    clearSpannable = true;                                        switch (mDefaultKeyMode) {                    case DEFAULT_KEYS_DIALER:                        Intent intent = new Intent(Intent.ACTION_DIAL,  Uri.parse("tel:" + str));                        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);                        startActivity(intent);                            break;                    case DEFAULT_KEYS_SEARCH_LOCAL:                        startSearch(str, false, null, false);                        break;                    case DEFAULT_KEYS_SEARCH_GLOBAL:                        startSearch(str, false, null, true);                        break;                    }                }            }            if (clearSpannable) {                mDefaultKeySsb.clear();                mDefaultKeySsb.clearSpans();                Selection.setSelection(mDefaultKeySsb,0);            }            return handled;        }    }    /**     * Default implementation of {@link KeyEvent.Callback#onKeyLongPress(int, KeyEvent)     * KeyEvent.Callback.onKeyLongPress()}: always returns false (doesn't handle     * the event).     */    public boolean onKeyLongPress(int keyCode, KeyEvent event) {        return false;    }    public boolean onKeyUp(int keyCode, KeyEvent event) {        if (getApplicationInfo().targetSdkVersion                >= Build.VERSION_CODES.ECLAIR) {            if (keyCode == KeyEvent.KEYCODE_BACK && event.isTracking()                    && !event.isCanceled()) {                onBackPressed();                return true;            }        }        return false;    }    /**     * Default implementation of {@link KeyEvent.Callback#onKeyMultiple(int, int, KeyEvent)     * KeyEvent.Callback.onKeyMultiple()}: always returns false (doesn't handle     * the event).     */    public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) {        return false;    }        /**     * Called when the activity has detected the user's press of the back     * key.  The default implementation simply finishes the current activity,     * but you can override this to do whatever you want.     */    public void onBackPressed() {        finish();    }    

  @Override    public void startActivity(Intent intent) {        startActivityForResult(intent, -1);    }

    public void startActivityFromChild(Activity child, Intent intent,             int requestCode) {        Instrumentation.ActivityResult ar =            mInstrumentation.execStartActivity(                this, mMainThread.getApplicationThread(), mToken, child,                intent, requestCode);        if (ar != null) {            mMainThread.sendActivityResult(                mToken, child.mEmbeddedID, requestCode,                ar.getResultCode(), ar.getResultData());        }    }

   public void finish() {        if (mParent == null) {            int resultCode;            Intent resultData;            synchronized (this) {                resultCode = mResultCode;                resultData = mResultData;            }            if (Config.LOGV) Log.v(TAG, "Finishing self: token=" + mToken);            try {                if (ActivityManagerNative.getDefault()                    .finishActivity(mToken, resultCode, resultData)) {                    mFinished = true;                }            } catch (RemoteException e) {                // Empty            }        } else {            mParent.finishFromChild(this);        }    }

  public void finishFromChild(Activity child) {        finish();    }    /**     * Force finish another activity that you had previously started with     * {@link #startActivityForResult}.     *      * @param requestCode The request code of the activity that you had     *                    given to startActivityForResult().  If there are multiple     *                    activities started with this request code, they     *                    will all be finished.     */    public void finishActivity(int requestCode) {        if (mParent == null) {            try {                ActivityManagerNative.getDefault()                    .finishSubActivity(mToken, mEmbeddedID, requestCode);            } catch (RemoteException e) {                // Empty            }        } else {            mParent.finishActivityFromChild(this, requestCode);        }    }
 {