android: 初始屏幕上的空指针

Question

我正在制作一个应用程序，我必须在启动画面中实现alpha 效果，当我加载图像时它会出现空指针异常。启动动画时的基本问题.如果我删除开始动画那么我的动画根本不会开始。我真的卡住了。任何帮助将不胜感激。我的代码如下:

public class SplashScreen extends Activity {


private Thread mSplashThread;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    System.out.println("hello");
    setContentView(R.layout.splash);

    final SplashScreen sPlashScreen = this; 

    Animation a1 = AnimationUtils.loadAnimation(this, R.anim.alpha);
        LinearLayout Ll=(LinearLayout)findViewById(R.id.mainLayoutheader);
        System.out.println("hello1");
        Ll.startAnimation(a1);
         System.out.println("hello2");


    // The thread to wait for splash screen events
    mSplashThread =  new Thread(){
        @Override
        public void run(){
            try {
                synchronized(this){
                    // Wait given period of time or exit on touch

                   // a.reset();


                    wait(6000);
                }
            }
            catch(InterruptedException ex){                    
            }

            finish();

            // Run next activity
            Intent intent = new Intent();
            intent.setClass(sPlashScreen, Main.class);
            startActivity(intent);
            stop();                    
        }
    };

    mSplashThread.start();        
}

} 

异常在 L1.startAnimation(a1);

Answer 1

我猜你忘了调用 setContentView。您必须在调用 findViewById 之前执行此操作 [编辑:此处未解决问题]