Android如何先显示一张图片，延时几秒后，再自动跳转到另一个页

public class Welocome extends Activity {
private final long SPLASH_LENGTH = 3000;
Handler handler = new Handler();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_welocome);
handler.postDelayed(new Runnable() {  //使用handler的postDelayed实现延时跳转

public void run() {
Intent intent = new Intent(Welocome.this, MainActivity.class);
startActivity(intent);
finish();
}
}, SPLASH_LENGTH);//3秒后跳转至应用主界面MainActivity
}
}
有不对的请大家多多指教