Activity exits twice and activityexits twice.

Activity exits twice and activityexits twice.

Let's take a look at the differences between onBackPressed and onKeyDown.

There are two ways to get the button event on Android

1. directly obtain the button and press the event. This method is compatible with Android 1.0 to Android 2.1 and is also a common method. You can directly rewrite the onKeyDown method of the Activity. The Code is as follows:

@ Override
Public boolean onKeyDown (int keyCode, KeyEvent event ){
If (keyCode = KeyEvent. KEYCODE_BACK) {// if you press BACK, there are no duplicates
Toast. makeText (ml78.this, "Back key test", 1). show ();
Return true;
}

Return super. onKeyDown (keyCode, event );
}

There is a new method for Android 2.0 at the beginning. For Activity, you can independently obtain the Back key press event and directly rewrite the onBackPressed method. The Code is as follows:

@ Override
Public void onBackPressed (){
// Process the logic code here. Note that this method is only applicable to sdk 2.0 or later versions.
Return;
}

1. Now, press 2 on the Root Activity to exit.

 

Private static boolean isSysExit = false; @ Override public void onBackPressed () {// TODO Auto-generated method stub if (! IsSysExit) {isSysExit = true; DensityUtil. showToast (this, "exit once again"); Timer timer = new Timer (); timer. schedule (new TimerTask () {@ Override public void run () {// TODO Auto-generated method stub isSysExit = false ;}, 2000 );} else {finish ();}}

 

2. Rewrite the back button in the root Activity to respond to the event. When you press the back button, move the Activity back to the background.

@ Override public boolean onKeyDown (int keyCode, KeyEvent event) {// TODO Auto-generated method stub // when you press the return key, move the Activity back to the background if (keyCode = KeyEvent. KEYCODE_BACK) {moveTaskToBack (true); return true;} return super. onKeyDown (keyCode, event );}