ServiceConnection 造成的内存泄漏

内存泄露日志

在项目中使用LeakCanary进行内存泄漏收集的时候出现了下面的一个memory leak：

06-23 11:23:08.512 10127-19987/org.xxx.xxx D/LeakCanary: In org.kingfeng.xxx:3.6.0:27.
   * org.kingfeng.xxx.activity.XXXActivity has leaked:
   * GC ROOT static org.xxx.xxx.application.MyApplication.myApplication
   * references org.xxx.xxx.application.MyApplication.mLoadedApk
   * references android.app.LoadedApk.mServices
   * references java.util.HashMap.table
   * references array java.util.HashMap$HashMapEntry[].[0]
   * references java.util.HashMap$HashMapEntry.value
   * references java.util.HashMap.table
   * references array java.util.HashMap$HashMapEntry[].[0]
   * references java.util.HashMap$HashMapEntry.key
   * references org.xxx.xxx.activity.XXXActivity$5.this$0 (anonymous class implements android.content.ServiceConnection)
   * leaks org.1.xxx.activity.XXXActivity instance  
   * Reference Key: 9e535d7a-b609-40f0-9c45-2e0f56711180
   * Device: HUAWEI Huawei MediaPad T1 8.0 msm8610
   * Android Version: 4.3 API: 18
   * Durations: watch=5028ms, gc=223ms, heap dump=1182ms, analysis=37294ms

功能实现

在activity中有：

ServiceConnection mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            if(service instanceof MyService.MyBinder) {
                myService = ((MyService.MyBinder) service).getService();
                myService.registerConnectionStatusCallback(XXXActivity.this);
            }
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            myService.unRegisterConnectionStatusCallback();
            myService = null;
        }
};

问题原因及解决思路

看了源码中 onServiceDisconnected(ComponentName name)方法注释：

/**
 * Called when a connection to the Service has been lost.  This typically
 * happens when the process hosting the service has crashed or been killed.
 * This does <em>not</em> remove the ServiceConnection itself -- this
 * binding to the service will remain active, and you will receive a call
 * to {@link #onServiceConnected} when the Service is next running.
 *
 * @param name The concrete component name of the service whose connection has been lost.
 */

意思就是通常情况下，在托管这个service的进程崩溃或者被杀死的情况下，这个方法才会调用。
也就是只是Activity销毁，这个方法并不会调用。导致connection持有 XXXActivity的引用，不能及时被GC回收，造成内存泄漏。
搞了好大一会儿才把这个问题解决掉，做个记录。

解决办法：
在Activity的onDestroy() 中：

@Override
protected void onDestroy() {
    super.onDestroy();
    if(myService != null) {
        myService.unRegisterConnectionStatusCallback();
    }
}

参考：
Android中Service的使用详解和注意点