1、利用Handler的postDelayed 

new Handler().postDelayed(new Runnable() {
    @Override
    public void run() {
        Intent intent = new Intent(MainActivity.this, 
                ExampleActivity.class);
        startActivity(intent);
    } 
}, 3000);   // 3秒后执行

2、利用timer的schedule

final Intent localIntent = new Intent(this, ExampleActivity.class);    
Timer timer = new Timer();    
TimerTask tast = new TimerTask() {    
    @Override    
    public void run() {    
        startActivity(localIntent);    
    }    
};    
timer.schedule(tast, 5000);    // 5秒后执行task的run