How can I use the Android back button to move back within my app instead of closing my app?

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迷失自我
迷失自我 2021-01-22 18:31

My app has three activities, A, B and C. I am moving from A to B through an OK button, and I want to move back from B to A by using the default back button of Android devices. W

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  • 2021-01-22 19:04

    why start your activity for result ? when you press the backbutton, the result is set to RESULT_CANCELED form the B activity, so it crashes if you don't handle the resultcode...

    you can handle the backpress like this

    private static final int NONE = -1;
    
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
    
        if (keyCode == KeyEvent.KEYCODE_BACK) {
    
       setResult(NONE, intent);
            finish();
        return super.onKeyDown(keyCode, event);
    }
    
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  • 2021-01-22 19:07

    In my onClick method (in Main Activity) I use the code:

     Intent intent = new Intent(context, SecondActivity.class);
     context.startActivityForResult(intent, SecondActivity.SECONDACTIVITY_REQUEST);
    

    In the manifest I've got:

     <activity android:name=".SecondActivity" android:screenOrientation="landscape" android:launchMode="standard"></activity>
    

    This works for me without any other settings that I can see. What events are you responding to?

    Note that you can also go back an activity, in code like this:

    super.setResult(Activity.RESULT_OK);
    super.finish();
    

    Edit... Make sure you're not swallowing the event in the Main Activitys onKeyDown event.

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        //your code here
        //if (keyCode ==
        //...
        //else
        return super.onKeyDown(keyCode, event);
    }
    
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  • 2021-01-22 19:10

    I suspect you call finish() in your OK button onclick listener. Don't do that. finish() removes your activity from activity stack.

    Read more here.

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  • 2021-01-22 19:12

    When you are Ok button r u starting an intent...like

    Intent int=new intent(context,B.class); startActivity(int);

    then if you are not handling backbutton.

    If use default back button...it will goes back to A.

    Hope it helps...

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