如何在整个Android应用程序中运行countdowntimer？

Question

I am trying to add countdowntimer in my application, i want to run timer for 5 minutes throughout an application without pause and cancel and as well as restart...I have tried several code but I didn't get desired output!

Problem faced: when I'm trying to intent from MainActivity to Main2Activity it works fine but If Main2Activity to MainActivity, timer get's restart!

//MainActivity.java

public class MainActivity extends AppCompatActivity  {
    Button button;
    TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button= (Button) findViewById(R.id.button);
        textView= (TextView) findViewById(R.id.id1);
        new CountDownTimer(300000, 1000) { // adjust the milli seconds here

            public void onTick(long millisUntilFinished) {
                textView.setText(""+String.format("%d min, %d sec",
                        TimeUnit.MILLISECONDS.toMinutes( millisUntilFinished),
                        TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) -
                                TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished))));
            }

            public void onFinish() {
                textView.setText("done!");
            }
        }.start();
        button.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v) {
                Intent in=new Intent(MainActivity.this,Main2Activity.class);
                startActivity(in);
            }
        });
    }
}

//Main2Activity.java

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        Button btn2= (Button) findViewById(R.id.button2);
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i=new Intent(Main2Activity.this,MainActivity.class);
                startActivity(i);
            }
        });
    }
}

Answer 1

Your Main2Activity is starting a new instance of MainActivity. If you want to return to the original MainActivity, use finish() instead of startActivity() .