How to go back to the previous screen in single time backbutton pressed and how to exit from application while back button pressed twice?

Question

I want to perform an operation like when i pressed back Button single time then it will move to the selected screen and when i pressed twice Back Button then it will show the dialog and ask for exit.

I tried many examples in stack overflow but none of them are helping me..

navaigation.java

    private int clickCount = 0;
    private long delay = 100;
    Timer timer = new Timer();

    @Override
    public void onBackPressed() {
        if (clickCount == 2) {
            super.onBackPressed();
            timer.cancel();
        } else{
            clickCount++;
            timer.schedule(new TimerTask() {
                @Override
                public void run() {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            backButtonHandler();
                        }
                    });
                }

        }, delay);
    }

}




public void backButtonHandler() {
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(
            Navigation.this);
    // Setting Dialog Title
    alertDialog.setTitle("Leave application?");
    // Setting Dialog Message
    alertDialog.setMessage("Are you sure you want to leave the application?");
    // Setting Icon to Dialog
    alertDialog.setIcon(R.drawable.m_visit);
    // Setting Positive "Yes" Button
    alertDialog.setPositiveButton("YES",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    finish();
                }
            });
    // Setting Negative "NO" Button
    alertDialog.setNegativeButton("NO",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // Write your code here to invoke NO event
                    dialog.cancel();
                }
            });
    // Showing Alert Message
    alertDialog.show();
}

I tried this way but it is not working properly...

Answer 1

Try this code:

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.widget.Toast;

public class MainActivity extends Activity {
private static final int TIME_DELAY = 2000;
private static long back_pressed;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

@Override
public void onBackPressed() {
    if (back_pressed + TIME_DELAY > System.currentTimeMillis()) {
        super.onBackPressed();
    } 
    else {
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
        alertDialogBuilder.setMessage("Are you sure, You wanted to exit");
        alertDialogBuilder.setPositiveButton("yes", 
        new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface arg0, int arg1) {
          finish();
        }
       });

        alertDialogBuilder.setNegativeButton("No",new
       DialogInterface.OnClickListener() {
       Override
       public void onClick(DialogInterface dialog, int which) {
        dismiss();
         }
       });

       AlertDialog alertDialog = alertDialogBuilder.create();
       alertDialog.show();
      }    
    }
    back_pressed = System.currentTimeMillis();
}