MediaPlayer中的IllegalStateException [英] IllegalStateException in MediaPlayer

问题描述

这是我的代码

if (player != null) {
    if(player.isPlaying()){
        player.pause();
        player.stop();
    }
    player.release();
}

这是错误

FATAL EXCEPTION: main
java.lang.IllegalStateException
at android.media.MediaPlayer.isPlaying(Native Method)
at com.mindefy.sindhipathshala.RecViewAdapter.mediafileRelease(RecViewAdapter.java:234)
at com.mindefy.sindhipathshala.SectionFruits.onBackPressed(SectionFruits.java:252)

我是Android的初学者，我对MediaPlayer的生命周期感到非常困惑.

I am a beginner in Android and i am very confused with the lifecycle of a MediaPlayer.

这是从另一个Activity的onBackPressed()函数调用的适配器中的函数. player是一个类变量.

This is a function in an adapter that is called from onBackPressed() function of another Activity. player is a class variable.

我将这个MediaPlayer发布到与

public void onClick(View v) {
    try {
        if (player != null) {
            player.stop();
            player.release();
        }
    } catch (Exception e) {
    }
    player = MediaPlayer.create(activityContext, soundId);
    player.start();
}

推荐答案

问题是您无法跟踪MediaPlayer实例的状态.

The problem is you don't keep track of the state of your MediaPlayer instance.

在调用isPlaying()之前，您只能执行null值检查，尽管player仍可以释放(但不能释放null).

Before calling isPlaying() you only perform a null value check, although player can still be released (but not null).

在已发布的MediaPlayer实例上调用isPlaying()将导致IllegalStateException .

Calling isPlaying() on a released MediaPlayer instance will result in an IllegalStateException.

为避免这种情况，例如，可以在释放它时将player设置为null:

To avoid this, you could for example set player to null when you release it:

player.release();
player = null;

或者您可以使用boolean标志来跟踪其状态:

Or you could use a boolean flag to keep track of its state:

boolean isReleased;

// ...

player.release();
isReleased = true;

因此您可以在必要时检查此标志:

So you could check for this flag when necessary:

if (player != null && !isReleased) {
    if(player.isPlaying()) {
        // ...
    }
}

(不要忘记在适当的时候将其设置为false)

(don't forget to set it to false when appropriate)

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