此 AsyncTask 类应该是静态的，否则可能会通过 YouTubeExtractor 发生泄漏

Question

我正在使用Youtube Extractor library

implementation 'com.github.HaarigerHarald:android-youtubeExtractor:master-SNAPSHOT'

我正在使用它在我的片段中获取 YouTube 下载 URL，一旦它完成提取就会上传到我的 firebase 数据库

if (requestCode==0000 && resultCode==getActivity().RESULT_OK){

            if (videoPath != null ) {
                for (String s : videoPath) {

                    new YouTubeExtractor(context) { // THIS LIBRARY SHOWING WARNING
                        @Override
                        protected void onExtractionComplete(SparseArray<YtFile> ytFiles, VideoMeta videoMeta) {
                            if (ytFiles !=null){
                                int itag = 18;
                                String link = ytFiles.get(18).getUrl();

                                Map<String, Object> map = new HashMap<>();
                                map.put("Message", link);

                                String Temp_Key = databaseReference.push().getKey();
                                Map<String, Object> RoomKey = new HashMap<>();
                                databaseReference.updateChildren(RoomKey);
                                DatabaseReference message_Root = databaseReference.child(Temp_Key);
                                message_Root.updateChildren(map);

                            }
                        }

                    }.extract(s, true, true);
                
                }
            }

我的问题是如何用这个库解决这个警告。我不想使用@SuppressLint("StaticFieldLeak")，它只会抑制警告而不是解决它。

Answer 1

为避免内存泄漏，您需要在 AsyncTask 中创建对活动/片段的周引用； here 是对此的完整解释，下面的代码示例

public class MyActivity extends AppCompatActivity {

int mSomeMemberVariable = 123;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // start the AsyncTask, passing the Activity context
    // in to a custom constructor 
    new MyTask(this).execute();
}

private static class MyTask extends AsyncTask<Void, Void, String> {

    private WeakReference<MyActivity> activityReference;

    // only retain a weak reference to the activity 
    MyTask(MyActivity context) {
        activityReference = new WeakReference<>(context);
    }

    @Override
    protected String doInBackground(Void... params) {

        // do some long running task...

        return "task finished";
    }

    @Override
    protected void onPostExecute(String result) {

        // get a reference to the activity if it is still there
        MyActivity activity = activityReference.get();
        if (activity == null || activity.isFinishing()) return;

        // modify the activity's UI
        TextView textView = activity.findViewById(R.id.textview);
        textView.setText(result);

        // access Activity member variables
        activity.mSomeMemberVariable = 321;
    }
}

}

还有其他 AsyncTask 的替代品，例如 Executor 和 AsyncTaskLoader，您可能会想到它们。希望这会有所帮助。