How to show a dialog to confirm that the user wish

Question

I've been trying to show a "Do you want to exit?" type of dialog when the user attempts to exit an Activity.

However I can't find the appropriate API hooks. Activity.onUserLeaveHint() initially looked promising, but I can't find a way to stop the Activity from finishing.

Answer 1

IF you are using fragment instead of activity put this code in your main activity

    private Toast toast;
    private long lastBackPressTime = 0;
    @SuppressLint("WrongConstant")
    @Override
    public void onBackPressed() {
        int fragments = getFragmentManager().getBackStackEntryCount();
        if (fragments == 0) {
            // make layout invisible since last fragment will be removed
            if (this.lastBackPressTime < System.currentTimeMillis() - 3000) {
                toast = Toast.makeText(this, "Press back again to close this app", 3000);
                toast.show();
                this.lastBackPressTime = System.currentTimeMillis();

            }else{
                if (toast != null) {
                    toast.cancel();
                }
                super.onBackPressed();
            }

        }else{
            if (toast != null) {
                toast.cancel();
            }
            super.onBackPressed();
        }
    }

Answer 2

In Android 2.0+ this would look like:

@Override
public void onBackPressed() {
    new AlertDialog.Builder(this)
        .setIcon(android.R.drawable.ic_dialog_alert)
        .setTitle("Closing Activity")
        .setMessage("Are you sure you want to close this activity?")
        .setPositiveButton("Yes", new DialogInterface.OnClickListener()
    {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            finish();    
        }

    })
    .setNegativeButton("No", null)
    .show();
}

In earlier versions it would look like:

@Override
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)
        .setIcon(android.R.drawable.ic_dialog_alert)
        .setTitle(R.string.quit)
        .setMessage(R.string.really_quit)
        .setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {

                //Stop the activity
                YourClass.this.finish();    
            }

        })
        .setNegativeButton(R.string.no, null)
        .show();

        return true;
    }
    else {
        return super.onKeyDown(keyCode, event);
    }

}

Answer 3

@Override
public void onBackPressed() {
    new AlertDialog.Builder(this)
           .setMessage("Are you sure you want to exit?")
           .setCancelable(false)
           .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
               public void onClick(DialogInterface dialog, int id) {
                   ExampleActivity.super.onBackPressed();
               }
           })
           .setNegativeButton("No", null)
           .show();
}

Answer 4

I'd prefer to exit with double tap on the back button than with an exit Dialog.

In this solution, it show a toast when go back for the first time, warning that another back press will close the App. In this example less than 4 seconds.

private Toast toast;
private long lastBackPressTime = 0;

@Override
public void onBackPressed() {
  if (this.lastBackPressTime < System.currentTimeMillis() - 4000) {
    toast = Toast.makeText(this, "Press back again to close this app", 4000);
    toast.show();
    this.lastBackPressTime = System.currentTimeMillis();
  } else {
    if (toast != null) {
    toast.cancel();
  }
  super.onBackPressed();
 }
}

Token from: http://www.androiduipatterns.com/2011/03/back-button-behavior.html

Answer 5

Using Lambda:

    new AlertDialog.Builder(this).setMessage(getString(R.string.exit_msg))
        .setTitle(getString(R.string.info))
        .setPositiveButton(getString(R.string.yes), (arg0, arg1) -> {
            moveTaskToBack(true);
            finish();
        })
        .setNegativeButton(getString(R.string.no), (arg0, arg1) -> {
        })
        .show();

You also need to set level language to support java 8 in your gradle.build:

compileOptions {
       targetCompatibility 1.8
       sourceCompatibility 1.8
}

Answer 6

in China, most App will confirm the exit by "click twice":

boolean doubleBackToExitPressedOnce = false;

@Override
public void onBackPressed() {
    if (doubleBackToExitPressedOnce) {
        super.onBackPressed();
        return;
    }

    this.doubleBackToExitPressedOnce = true;
    Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();

    new Handler().postDelayed(new Runnable() {

        @Override
        public void run() {
            doubleBackToExitPressedOnce=false;                       
        }
    }, 2000);
}