Android几秒后更改活动

Question

I need some help with my first Android project. I want to write a app which is showing you a picture with a ImageView for a few seconds I would say so about 4 seconds and after that it change to a second activity which shows a button(only for testing).

My Problem is that my app after I started it in my AVD jump over the picture and shows immediately the button.

How can I fix it? I looked up so long and tried so many things I hope someone of you have a idea :)

Thanks for helping

Here my Code of my MainActivity:

     package com.example.parkourspots;
 public class MainActivity extends Activity {

private ViewTreeObserver vto;

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

    final View myLayout = findViewById(R.id.startscreen);

    vto = myLayout.getViewTreeObserver();



    vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener(){

        @Override
        public void onGlobalLayout(){
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            Intent intent = new Intent(MainActivity.this, select_activity_class.class);

            startActivity(intent);


    }
}); 


}}

Answer 1

Check this code.

package com.example.parkourspots;

public class MainActivity extends Activity {
    private static int TIME_OUT = 4000; //Time to launch the another activity
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final View myLayout = findViewById(R.id.startscreen);
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                Intent i = new Intent(MainActivity.this, ActivityTwo.class);
                startActivity(i);
                finish();
            }
        }, TIME_OUT);
    }
}); 

Answer 2

You can try:

public class MainActivity extends Activity {
    private Handler mHandler = new Handler();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mHandler.postDelayed(new Runanble() {
            @Override
            public void run() {
                Intent intent = new Intent(MainActivity.this, select_activity_class.class);
                startActivity(intent);
            }
        }, 4000); // 4 seconds
    }
}

In addiction, you may add this for your second activity declaration in AndroidManifest: android:finishOnTaskLaunch="true"

Answer 3

1)Sleeping 500 only sleeps for .5 seconds. So it would blink quickly anyway

2)Sleeping doesn't allow the thread to get back to the looper, so it freezes your UI. This means it won't update and draw anyway. Use a timer instead. Or posting a message to a handler would be acceptable here.

Answer 4

The problem is you're only sleeping for 500 milliseconds (half of one second), so it makes sense that it happens seemingly-immediately. You're also going to want to remove the OnGlobalLayoutListener after it's called. Here's an example of an approach that should work for you:

final Handler handler = new Handler(); // Create a Handler on the main Thread
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener(){

    @Override
    public void onGlobalLayout(){
        removeOnGlobalLayoutListener(vto, this);
        handler.postDelayed(new Runnable(){
             public void run(){
                 Intent intent = new Intent(MainActivity.this, select_activity_class.class);
                 startActivity(intent);
             }
        }, 4000); //Post back to the main Thread after 4000 mils (4 seconds)
    }
}); 

@SuppressLint("NewApi")
public static void removeOnGlobalLayoutListener(View v, ViewTreeObserver.OnGlobalLayoutListener listener){
    if (Build.VERSION.SDK_INT < 16) v.getViewTreeObserver().removeGlobalOnLayoutListener(listener); 
    else v.getViewTreeObserver().removeOnGlobalLayoutListener(listener);
}

Answer 5

never stall the UI thread. The UI thread is responsible for keeping your app feeling responsive.

But this is an fast and alternative solution for your problem.

public class MyActivity extends Activity {
private Handler mHandler = new Handler();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mHandler.postDelayed(new Runnable() {
        public void run() {
            doStuff();
        }
    }, 5000);
}

private void doStuff() {
    Intent intent = new Intent(MainActivity.this, select_activity_class.class);

        startActivity(intent);
}
}

Then 5 seconds after the intent must start.

But i recommend async task

Answer 6

Proper and short solution

Make a handler and give them a delay to call back itself:

final Handler h = new Handler();

h.postDelayed(new Runnable() {

   @Override

   public void run() {

     //Do something after 1s   

   }

}, 1000);

Remember that 1 sec = 1000 milliseconds

Adjust time with that formula.

Happy Coding.