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[英]Getting value from table that is empty in sqlite android-Showing Null Pointer Exception
[英]Null pointer exception on getting value from onRetainNonConfigurationInstance() - Android
我正在开发一个应用程序,它可以使用不同的Mediaplayer实例同时播放2个音频文件。 在屏幕旋转时保持媒体播放器状态的方法
public Object onRetainNonConfigurationInstance()
{
HashMap<String,Object> player = new HashMap<String,Object>();
MediaPlayer instance = mp;
mp = null;
MediaPlayer instance1 = mp1;
mp1 = null;
player.put("mp", instance);
player.put("mp1", instance1);
return player;
}
在onCreate()中,
HashMap<String, Object> playerhandle = (HashMap<String, Object>)getLastNonConfigurationInstance();
mp = (MediaPlayer)playerhandle.get("mp");
if (mp == null)
{
mp = new MediaPlayer();
}
mp1 = (MediaPlayer)playerhandle.get("mp1");
if (mp1 == null)
{
mp1 = new MediaPlayer();
}
在logcat中显示NullPointerException。
您永远不会检查playerhandle
是否为null
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