Android: Capture the BACK button keypress and display a confirmation dialog

An often useful feature to have is the "Are you sure you wish to exit?" confirmation as someone may accidently touch the back button and exit your application.

To add that, we need to first override onKeyDown() in the application and detect the BACK button keypress.

public boolean onKeyDown(int keyCode, KeyEvent event) {
//Handle the back button
if (keyCode == KeyEvent.KEYCODE_BACK) {
//Ask the user if they want to quit
new AlertDialog.Builder(this)
.setMessage("Are you sure you want to leave?")
.setNegativeButton(android.R.string.cancel, null)
.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which){
// Exit the activity

// Say that we've consumed the event
return true;

return super.onKeyDown(keyCode, event);

A word of warning, in Android 2.0 there is a handler purely for the back button called onBackPressed().

[ Source, Docs, onBackPressed() ]

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