com.neovisionaries.android.app

Class BaseRootActivity

java.lang.Object

android.content.Context

android.content.ContextWrapper

android.view.ContextThemeWrapper

android.app.Activity

com.neovisionaries.android.app.BaseRootActivity

All Implemented Interfaces:

android.content.ComponentCallbacks, android.view.KeyEvent.Callback, android.view.LayoutInflater.Factory, android.view.View.OnCreateContextMenuListener, android.view.Window.Callback

public abstract class BaseRootActivity
extends android.app.Activity

Base class for a root Activity of an application whose all the other Activities honor the chain of finish() mechanism.

A subclass of this class is expected to be set as the main activity in AndroidManifest.xml like the following.

 <activity android:name=".RootActivity" >
     <intent-filter>
         <action android:name="android.intent.action.MAIN" />
         <category android:name="android.intent.category.LAUNCHER" />
     </intent-filter>
 </activity>

Sub classes are required to implement dispatch() method which is expected to launch another Activity. A simple example of a root Activity that extends BaseRootActivity is shown below.

 public class RootActivity extends BaseRootActivity
 {
     @Override
     public void onCreate(Bundle savedInstance)
     {
         super.onCreate(savedInstance);

         setContentView(R.layout.root_activity);
     }

     @Override
     protected void dispatch()
     {   
         // Start HomeActivity. Activities launched from here
         // should call App.getInstance().setStopping(true)
         // when they receive a key down event of KEYCODE_BACK.
         // Otherwise, such Activities will be re-launched by
         // the onResume() implementation of BaseRootActivity.
         // You may find BottomActivity and its variants useful.
         startActivity(new Intent(this, HomeActivity.class));

         // Note that finish() should not be called here.
         // This RootActivity instance should sit at the
         // bottom of the Activity stack in order to benefit
         // from the default mechanism of Android's Activity
         // management.
     }
 }

The implementation of onDestroy() method of this class does the following to support restarting.

1. Emit a log message saying "STOPPED".
2. Check if the application is in the process of restart (= check if App.getInstance().isRestarting() returns true).
3. If the application is in the process of restart, create an Intent with ACTION_MAIN & CATEGORY_LAUNCHER and pass it to Activity.startActivity(Intent), and the call App.getInstance().setRestarting(false).

Author:

Takahiko Kawasaki

Field Summary

Fields inherited from class android.app.Activity

DEFAULT_KEYS_DIALER, DEFAULT_KEYS_DISABLE, DEFAULT_KEYS_SEARCH_GLOBAL, DEFAULT_KEYS_SEARCH_LOCAL, DEFAULT_KEYS_SHORTCUT, FOCUSED_STATE_SET, RESULT_CANCELED, RESULT_FIRST_USER, RESULT_OK

Fields inherited from class android.content.Context

ACCESSIBILITY_SERVICE, ACCOUNT_SERVICE, ACTIVITY_SERVICE, ALARM_SERVICE, AUDIO_SERVICE, BIND_AUTO_CREATE, BIND_DEBUG_UNBIND, BIND_NOT_FOREGROUND, CLIPBOARD_SERVICE, CONNECTIVITY_SERVICE, CONTEXT_IGNORE_SECURITY, CONTEXT_INCLUDE_CODE, CONTEXT_RESTRICTED, DEVICE_POLICY_SERVICE, DROPBOX_SERVICE, INPUT_METHOD_SERVICE, KEYGUARD_SERVICE, LAYOUT_INFLATER_SERVICE, LOCATION_SERVICE, MODE_APPEND, MODE_PRIVATE, MODE_WORLD_READABLE, MODE_WORLD_WRITEABLE, NOTIFICATION_SERVICE, POWER_SERVICE, SEARCH_SERVICE, SENSOR_SERVICE, TELEPHONY_SERVICE, UI_MODE_SERVICE, VIBRATOR_SERVICE, WALLPAPER_SERVICE, WIFI_SERVICE, WINDOW_SERVICE

Constructor Summary

Constructors

Constructor and Description
BaseRootActivity()

Method Summary

Modifier and Type	Method and Description
protected abstract void	dispatch() Launch another Activity.
protected void	onCreate(android.os.Bundle savedInstanceState) Called when this Activity gets started.
protected void	onDestroy() Called when this Activity gets stopped.
protected void	onResume() Called when this Activity gets resumed.

Methods inherited from class android.app.Activity

addContentView, closeContextMenu, closeOptionsMenu, createPendingResult, dismissDialog, dispatchKeyEvent, dispatchPopulateAccessibilityEvent, dispatchTouchEvent, dispatchTrackballEvent, findViewById, finish, finishActivity, finishActivityFromChild, finishFromChild, getApplication, getCallingActivity, getCallingPackage, getChangingConfigurations, getComponentName, getCurrentFocus, getInstanceCount, getIntent, getLastNonConfigurationInstance, getLayoutInflater, getLocalClassName, getMenuInflater, getParent, getPreferences, getRequestedOrientation, getSystemService, getTaskId, getTitle, getTitleColor, getVolumeControlStream, getWallpaperDesiredMinimumHeight, getWallpaperDesiredMinimumWidth, getWindow, getWindowManager, hasWindowFocus, isChild, isFinishing, isTaskRoot, managedQuery, moveTaskToBack, onActivityResult, onApplyThemeResource, onAttachedToWindow, onBackPressed, onChildTitleChanged, onConfigurationChanged, onContentChanged, onContextItemSelected, onContextMenuClosed, onCreateContextMenu, onCreateDescription, onCreateDialog, onCreateDialog, onCreateOptionsMenu, onCreatePanelMenu, onCreatePanelView, onCreateThumbnail, onCreateView, onDetachedFromWindow, onKeyDown, onKeyLongPress, onKeyMultiple, onKeyUp, onLowMemory, onMenuItemSelected, onMenuOpened, onNewIntent, onOptionsItemSelected, onOptionsMenuClosed, onPanelClosed, onPause, onPostCreate, onPostResume, onPrepareDialog, onPrepareDialog, onPrepareOptionsMenu, onPreparePanel, onRestart, onRestoreInstanceState, onRetainNonConfigurationInstance, onSaveInstanceState, onSearchRequested, onStart, onStop, onTitleChanged, onTouchEvent, onTrackballEvent, onUserInteraction, onUserLeaveHint, onWindowAttributesChanged, onWindowFocusChanged, openContextMenu, openOptionsMenu, overridePendingTransition, registerForContextMenu, removeDialog, requestWindowFeature, runOnUiThread, setContentView, setContentView, setContentView, setDefaultKeyMode, setFeatureDrawable, setFeatureDrawableAlpha, setFeatureDrawableResource, setFeatureDrawableUri, setIntent, setPersistent, setProgress, setProgressBarIndeterminate, setProgressBarIndeterminateVisibility, setProgressBarVisibility, setRequestedOrientation, setResult, setResult, setSecondaryProgress, setTitle, setTitle, setTitleColor, setVisible, setVolumeControlStream, showDialog, showDialog, startActivity, startActivityForResult, startActivityFromChild, startActivityIfNeeded, startIntentSender, startIntentSenderForResult, startIntentSenderFromChild, startManagingCursor, startNextMatchingActivity, startSearch, stopManagingCursor, takeKeyEvents, triggerSearch, unregisterForContextMenu

Methods inherited from class android.view.ContextThemeWrapper

attachBaseContext, getTheme, setTheme

Methods inherited from class android.content.ContextWrapper

bindService, checkCallingOrSelfPermission, checkCallingOrSelfUriPermission, checkCallingPermission, checkCallingUriPermission, checkPermission, checkUriPermission, checkUriPermission, clearWallpaper, createPackageContext, databaseList, deleteDatabase, deleteFile, enforceCallingOrSelfPermission, enforceCallingOrSelfUriPermission, enforceCallingPermission, enforceCallingUriPermission, enforcePermission, enforceUriPermission, enforceUriPermission, fileList, getApplicationContext, getApplicationInfo, getAssets, getBaseContext, getCacheDir, getClassLoader, getContentResolver, getDatabasePath, getDir, getExternalCacheDir, getExternalFilesDir, getFilesDir, getFileStreamPath, getMainLooper, getPackageCodePath, getPackageManager, getPackageName, getPackageResourcePath, getResources, getSharedPreferences, getWallpaper, grantUriPermission, isRestricted, openFileInput, openFileOutput, openOrCreateDatabase, peekWallpaper, registerReceiver, registerReceiver, removeStickyBroadcast, revokeUriPermission, sendBroadcast, sendBroadcast, sendOrderedBroadcast, sendOrderedBroadcast, sendStickyBroadcast, sendStickyOrderedBroadcast, setWallpaper, setWallpaper, startInstrumentation, startService, stopService, unbindService, unregisterReceiver

Methods inherited from class android.content.Context

getString, getString, getText, obtainStyledAttributes, obtainStyledAttributes, obtainStyledAttributes, obtainStyledAttributes

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BaseRootActivity

public BaseRootActivity()

Method Detail

onResume

protected final void onResume()

Called when this Activity gets resumed. The implementation of this method does the following.

1. Calls super.onResume().
   
   
2. Calls App.getInstance().isStopping() and if the return value is true, calls finish() and executes App.getInstance().setStopping(false). The finish() call terminates this application (if the subclass of BaseRootActivity is used as the root Activity). The reason to call App.getInstance().setStopping(false) is that Android may reuse this Activity instance instead of creating a new one.
   
   
3. Otherwise, calls dispatch() that subclasses must implement.
   
   

Note that if a subclass of BaseRootActivity is used as the root Activity, the application won't terminate until App.getInstance().setStopping(true) is explicitly called. You may find BaseActivity.exit() useful to stop your application.

Overrides:

onResume in class android.app.Activity

dispatch

protected abstract void dispatch()

Launch another Activity.

This method is called from the context of onResume() if and only if App.getInstance().isStopping() returned false when onResume() of this Activity was called. Implementations of this method are expected to invoke another Activity.

Note that implementations of this method should not call finish() after invoking another Activity. It is because the purpose of the root Activity is to sit at the bottom of the Activity stack so that this application can benefit from the default mechanism of Android's Activity management.

Activities launched from within dispatch() method should call App.getInstance().setStopping(true) when they receive a key down event of KEYCODE_BACK. Otherwise, such Activities will be re-launched by the onResume() implementation of BaseRootActivity. A simple way to satisfy the requirement is to use BottomActivity or its variants whose onKeyDown method calls App.getInstance().setStopping(true).

onCreate

protected void onCreate(android.os.Bundle savedInstanceState)

Called when this Activity gets started.

This method is the best point to re-initialize the application. In other words, this is the logical starting point of the application. (The 'physical' starting point of the application is onCreate() of android.app.Application.)

The implementation of this method emits "STARTED" log message.

Overrides:

onCreate in class android.app.Activity

See Also:

BaseApplication.onCreate()

onDestroy

protected void onDestroy()

Called when this Activity gets stopped.

This method is the best point to finalize the application. In other words, this is the logical end point of the application. (The 'physical' end point of the application is onTerminate() of android.app.Application.)

The implementation of this method emits "STOPPED" log message. And then, if required (= if App.getInstance().isRestarting() returns true), this implementation restarts this activity by passing an Intent with ACTION_MAIN & CATEGORY_LAUNCHER to Activity.startActivity(Intent). In such a case, "RESTARTING" log message is emitted.

Overrides:

onDestroy in class android.app.Activity

See Also:

BaseApplication.onTerminate()