java - 为什么 MediaPlayer 在 Android 中的应用程序重新启动状态下停止？

Question

我制作了一个音板应用程序，它可以工作，但是当我按下手机上的主页按钮时我单击以恢复应用程序，当我按下声音按钮时，它停止工作(崩溃)

private MediaPlayer mp;
 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mp = MediaPlayer.create(this, R.raw.iaminevitable);

        iaminevitable = (Button) findViewById(R.id.iaminevitable);
        iaminevitable.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mp.start();
            }
        });

 @Override
    protected void onStop() {
        super.onStop();
        if (mp != null) {
            mp.reset();
            mp.release();
            mp = null;
        }

我的错误 Logcat =

Process: soundboard.test, PID: 5429
    java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaPlayer.start()' on a null object reference
        at soundboard.test.MainActivity$6.onClick(MainActivity.java:96)
        at android.view.View.performClick(View.java:4780)
        at android.view.View$PerformClick.run(View.java:19866)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5293)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

Answer 1

您是否已授予所需的权限？检查它并请向存储等添加更多代码，或者如果问题是 Activity 生命周期，只需添加此代码

@Override
public void onRestart()
{
    super.onRestart();
     recreate();
    finish();
    overridePendingTransition(0, 0);
    startActivity(getIntent());
    overridePendingTransition(0, 0);
}