由於內部類會持有外部類的引用,因此handler的一般寫法在退出activity之後會導致內存泄漏,所有必須在activity的相關生命週期方法中及時清理掉handler的消息,並且規範handler的寫法
import java.lang.ref.WeakReference;
public class Status extends SettingsPreferenceFragment {
private Handler mHandler;
private static class MyHandler extends Handler {
private WeakReference<Status> mStatus;// 聲明外部類的弱引用,避免導致內存泄漏
public MyHandler(Status activity) {
mStatus = new WeakReference<Status>(activity);
}
@Override
public void handleMessage(Message msg) {
Status status = mStatus.get();
if (status == null) {
return;
}
switch (msg.what) {
// 處理邏輯
}
}
}
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
mHandler = new MyHandler(this);
}
@Override
public void onResume() {
super.onResume();
mHandler.sendEmptyMessage(EVENT_UPDATE_STATS);
}
@Override
public void onPause() {
super.onPause();
mHandler.removeMessages(EVENT_UPDATE_STATS);// 移除消息,避免內存泄漏,可根據業務放在onstop或者ondestroy
}
}
```