Warning: This Asynctask Class Should Be Static or Leaks Might Occur

Warning: This AsyncTask class should be static or leaks might occur

How to use a static inner AsyncTask class

To prevent leaks, you can make the inner class static. The problem with that, though, is that you no longer have access to the Activity's UI views or member variables. You can pass in a reference to the Context but then you run the same risk of a memory leak. (Android can't garbage collect the Activity after it closes if the AsyncTask class has a strong reference to it.) The solution is to make a weak reference to the Activity (or whatever Context you need).

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;
        }
    }
}

Notes

As far as I know, this type of memory leak danger has always been true, but I only started seeing the warning in Android Studio 3.0. A lot of the main AsyncTask tutorials out there still don't deal with it (see here, here, here, and here).
You would also follow a similar procedure if your AsyncTask were a top-level class. A static inner class is basically the same as a top-level class in Java.
If you don't need the Activity itself but still want the Context (for example, to display a Toast), you can pass in a reference to the app context. In this case the AsyncTask constructor would look like this:
```
private WeakReference<Application> appReference;

MyTask(Application context) {
    appReference = new WeakReference<>(context);
}
```
There are some arguments out there for ignoring this warning and just using the non-static class. After all, the AsyncTask is intended to be very short lived (a couple seconds at the longest), and it will release its reference to the Activity when it finishes anyway. See this and this.
Excellent article: How to Leak a Context: Handlers & Inner Classes

Kotlin

In Kotlin just don't include the inner keyword for the inner class. This makes it static by default.

class MyActivity : AppCompatActivity() {

    internal var mSomeMemberVariable = 123

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

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

    private class MyTask
    internal constructor(context: MyActivity) : AsyncTask<Void, Void, String>() {

        private val activityReference: WeakReference<MyActivity> = WeakReference(context)

        override fun doInBackground(vararg params: Void): String {

            // do some long running task...

            return "task finished"
        }

        override fun onPostExecute(result: String) {

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

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

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

This AsyncTask class should be static or leaks might occur (anonymous android.os.AsyncTask)

Create a separate class that implements AsyncTask, then in your activity instantiate it, and run the execute method.

This Loader class should be static or leaks might occur | Inner class memory leak | AsyncTaskLoader memory leak -

The Solution is to create an Another class and make it static.

Then Extend AsynctaskLoader from the new Created Static class.
Ex - public static class ExtendsAysncTaskLoader extend AsynctaskLoader

create a member variables - Cursor

Create a Constructor for the Class with parameters(Context context, Cursor)

call the Constructor of the parent class using super method and pass the context.

set the member variable equal to the constructor.

override onStartLoading and LoadInbackground and implement it as explained in the todo (But be sure you would use the member variable created in the new class) here in the newly created static class.

In the onCreateLoader method - return the new class with the parameter
Ex - return new ExtendsAysncTaskLoader ( this,Cursor);

The Error will goes away now because we are using a static class named ExampleAsync which inherit the AsyncTaskLoader and Memory Leaks would not occur.

Example Class -

    public static class ExtendsAysncTaskLoader extends AsyncTaskLoader<Cursor>{

        Cursor mTaskData; 

    public ExtendsAysncTaskLoader(Context context, Cursor cursor) {
                super(context);
                mTaskData = cursor;
            }

     // onStartLoading() is called when a loader first starts loading data
    @Override
    protected void onStartLoading() {
        if (mTaskData != null) {
            // Delivers any previously loaded data immediately
            deliverResult(mTaskData);
        } else {
            // Force a new load
            forceLoad();
        }
    }

    // loadInBackground() performs asynchronous loading of data
    @Override
    public Cursor loadInBackground() {
        // Will implement to load data

        // Query and load all task data in the background; sort by priority
        // [Hint] use a try/catch block to catch any errors in loading data

        try {
            return getContentResolver().query(TaskContract.TaskEntry.CONTENT_URI,
                    null,
                    null,
                    null,
                    TaskContract.TaskEntry.COLUMN_PRIORITY);

        } catch (Exception e) {
            Log.e(TAG, "Failed to asynchronously load data.");
            e.printStackTrace();
            return null;
        }
    }

    // deliverResult sends the result of the load, a Cursor, to the registered listener
    public void deliverResult(Cursor data) {
        mTaskData = data;
        super.deliverResult(data);
    }
};

}

    OnCreateLoader() Example -

    @Override
        public Loader<String> onCreateLoader(int id, final Bundle args) {

           Cursor mTaskData = null;                

            return new ExtendsAysncTaskLoader(this,mTaskData);


        }

Hope this Helps

Warning: This Asynctask Class Should Be Static or Leaks Might Occur