安卓媒体播放器 : start method crashing

Question

我正在学习 thenewboston 的教程，但我遇到了一个问题，虽然我的代码看起来与视频中那个人的代码相同，但它不起作用。

public class Splash extends Activity{

MediaPlayer ourSong;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.splash);
    MediaPlayer.create(Splash.this, R.raw.splashsound);
    ourSong.start();
    Thread timer = new Thread(){
        public void run(){
            try{
                sleep(5000);
            } catch (InterruptedException e){
                e.printStackTrace();
            }finally{
                Intent openStartingPoint = new Intent("com.example.tutorial.STARTINGPOINT");
                startActivity(openStartingPoint);
            }
        }
    };
    timer.start();
}

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    //ourSong.release();
    finish();
    }
}

我试着把//放在涉及 MediaPlayer 的每一行之前，然后一个一个地取消注释，看起来程序在到达 ourSong.start() 时崩溃了。

我不知道为什么会这样。有人可以帮助我吗？

这是视频:https://www.youtube.com/watch?v=-zGS_zrL0rY&index=17&list=PLEFA63803DBD4C83A

Logcat 输出:

04-16 16:40:18.964: I/art(1829): Background partial concurrent mark sweep GC freed 91(16KB) AllocSpace objects, 0(0B) LOS objects, 28% free, 10MB/14MB, paused 12.573ms total 114.113ms

04-16 16:40:19.067: E/MediaPlayer(1829): Should have subtitle controller already set

04-16 16:40:19.070: D/AndroidRuntime(1829): Shutting down VM

04-16 16:40:19.090: E/AndroidRuntime(1829): FATAL EXCEPTION: main

04-16 16:40:19.090: E/AndroidRuntime(1829): Process: com.example.tutorial, PID: 1829

04-16 16:40:19.090: E/AndroidRuntime(1829): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.tutorial/com.example.tutorial.Splash}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaPlayer.start()' on a null object reference

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.app.ActivityThread.access$800(ActivityThread.java:151)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.os.Handler.dispatchMessage(Handler.java:102)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.os.Looper.loop(Looper.java:135)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.app.ActivityThread.main(ActivityThread.java:5257)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at java.lang.reflect.Method.invoke(Native Method)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at java.lang.reflect.Method.invoke(Method.java:372)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

04-16 16:40:19.090: E/AndroidRuntime(1829): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaPlayer.start()' on a null object reference

04-16 16:40:19.090: E/AndroidRuntime(1829):     at com.example.tutorial.Splash.onCreate(Splash.java:17)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.app.Activity.performCreate(Activity.java:5990)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)

04-16 16:40:19.090: E/AndroidRuntime(1829):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)

04-16 16:40:19.090: E/AndroidRuntime(1829):     ... 10 more

04-16 16:40:28.664: I/Process(1829): Sending signal. PID: 1829 SIG: 9

Answer 1

您的媒体播放器对象未初始化。为空!

ourSong = MediaPlayer.create(Splash.this, R.raw.splashsound);我们的歌曲.start();