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按下“主页”或“返回”时,在Android中优雅地关闭应用程序

forceclose android

-3

Si8 · 技术社区 · 11 年前

我有一个android应用程序,可以播放声音,但当我按HOME/BACK时,我希望声音停止并关闭应用程序,当用户返回应用程序时,我想再次启动活动,而不是继续。

我的onPause()代码:

@Override
protected void onPause()
{
    super.onPause();
    if (pS.isPlaying()) {
        pS.pause(); //stop the sound
        finish();
    }
    else
        finish();
}

当声音播放时,我点击主页或返回我的应用程序FC,并在下面发布日志:

04-02 13:06:40.563: E/AndroidRuntime(925): FATAL EXCEPTION: main
04-02 13:06:40.563: E/AndroidRuntime(925): java.lang.RuntimeException: Unable to pause activity {com.testcom.myapp/com.testcom.myapp.MyappActivity}: java.lang.NullPointerException
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2354)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2311)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:2291)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.ActivityThread.access$1700(ActivityThread.java:117)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:938)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.os.Looper.loop(Looper.java:123)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.ActivityThread.main(ActivityThread.java:3683)
04-02 13:06:40.563: E/AndroidRuntime(925):  at java.lang.reflect.Method.invokeNative(Native Method)
04-02 13:06:40.563: E/AndroidRuntime(925):  at java.lang.reflect.Method.invoke(Method.java:507)
04-02 13:06:40.563: E/AndroidRuntime(925):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-02 13:06:40.563: E/AndroidRuntime(925):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
04-02 13:06:40.563: E/AndroidRuntime(925):  at dalvik.system.NativeStart.main(Native Method)
04-02 13:06:40.563: E/AndroidRuntime(925): Caused by: java.lang.NullPointerException
04-02 13:06:40.563: E/AndroidRuntime(925):  at com.testcom.myapp.MyappActivity.onPause(MyappActivity.java:119)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.Activity.performPause(Activity.java:3851)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.Instrumentation.callActivityOnPause(Instrumentation.java:1191)
04-02 13:06:40.563: E/AndroidRuntime(925):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2341)
04-02 13:06:40.563: E/AndroidRuntime(925):  ... 12 more

笔记 :如果正在播放声音并按下HOME/BACK(主页/后退),应用程序会很好地关闭,但如果在按下HOME/BACK(主页/返回)时没有声音播放应用程序FC。我该如何解决问题?

2 回复 | 直到 11 年前

1

4

Raghav Sood 11 年前

尝试:

@Override
protected void onPause()
{
    super.onPause();
    if (pS!= null && pS.isPlaying()) {
        pS.pause(); //stop the sound
        finish();
    }
    else
        finish();
}

我猜很可能在没有声音的情况下 pS 变量为null,因此在使用它时会得到一个NPE。

2

0

Viswanath Lekshmanan 11 年前

没有必要在活动生命周期中等待onpause(),然后tat u才能完成活动()

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) 
{     

if(keyCode == KeyEvent.KEYCODE_HOME||keyCode == KeyEvent.KEYCODE_BACK)
{
    if (ps!=null) {
    pS.pause(); //stop the sound
    finish();
}
else
  finish();
}
});