android - overriding the back button

Question

I have a webView inside an Activity's layout. If back button is pressed, I want that view to disappear and other views to become visible, to I did the following:

    @Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK && web.getVisibility()==View.VISIBLE) {
        restoreInitalState(); // set Visibility of Views
        APP_CONSTANTS.LOGIN_OP_CANCELLED(getApplicationContext()); // inform the user that the current operation was cancelled
    }
    return super.onKeyDown(keyCode, event);

}

it works BUT it finishes the Activity immediately after calling my methods, like if the back button was pressed 2 times. I need to keep the current Activity and just call my methods mentioned above. Any suggestions?

score 3 · Accepted Answer · answered Feb 25 '13 at 17:47

You need to return false. Change this:

if (keyCode == KeyEvent.KEYCODE_BACK && web.getVisibility()==View.VISIBLE) {
    restoreInitalState(); // set Visibility of Views
    APP_CONSTANTS.LOGIN_OP_CANCELLED(getApplicationContext()); // inform the user that the current operation was cancelled
}

to this:

if (keyCode == KeyEvent.KEYCODE_BACK && web.getVisibility()==View.VISIBLE) {
    restoreInitalState(); // set Visibility of Views
    APP_CONSTANTS.LOGIN_OP_CANCELLED(getApplicationContext()); // inform the user that the current operation was cancelled
    return false;
}

score 1 · Answer 2 · answered Feb 25 '13 at 17:49

I think the correct method is:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK && web.getVisibility()==View.VISIBLE) {
        restoreInitalState(); // set Visibility of Views
        APP_CONSTANTS.LOGIN_OP_CANCELLED(getApplicationContext()); 
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

score 1 · Answer 3 · answered Feb 25 '13 at 17:51

1

Or just use the method, onBackPressed() in youe Activity class ,that's the simplest way to Override it.

answered Feb 25 '13 at 17:51

AbdulHannan

358
1
15

score 1 · Answer 4 · edited Feb 25 '13 at 18:13

1

I think the callback method you are looking for is onBackPressed.

But your current solution should work as well, you just need to return true inside your if-block otherwise the event will be propagated to another callback.

edited Feb 25 '13 at 18:13

Emil

7,220
17
76
135

answered Feb 25 '13 at 17:54

Exoit

76
3

android - overriding the back button

4 Answers4