IssueTracker

Library used (support-v4, appcompat-v7, ...):
Version used: 27.1.0
Theme used: -
Devices/Android versions reproduced on: emulator 26 (but doesnt matter)

To see
normal behaviour(expected): press "Pick something and edit(framework)" then follow instruction
support behaviour(bug): press "Pick something and edit(support)" then follow instruction

as you can see with support we stuck in EditActivity as onLoadFinished is called even without init/restart

the code:

package pl.selvin.android.support27bug;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.AsyncTaskLoader;
import android.support.v4.content.Loader;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.Random;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    final static int PICK_CODE = 666;
    final static int PICK_CODE_SUPPORT = 667;
    final static int LOADER_ID = 666;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final Button support = new Button(this);
        support.setText("Pick something and edit(support)");
        support.setTag(PICK_CODE_SUPPORT);
        support.setOnClickListener(this);
        final Button framework = new Button(this);
        framework.setText("Pick something and edit(framework)");
        framework.setTag(PICK_CODE);
        framework.setOnClickListener(this);
        final LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        layout.addView(framework);
        layout.addView(support);
        setContentView(layout);
    }

    @Override
    public void onClick(View v) {
        startActivityForResult(new Intent(MainActivity.this, PickActivity.class), (int) v.getTag());
    }

    private final LoaderManager.LoaderCallbacks<Integer> mSupportInsertLoaderCallback = new LoaderManager.LoaderCallbacks<Integer>() {

        @Override
        public Loader<Integer> onCreateLoader(int id, Bundle args) {
            return new SupportInsertLoader(MainActivity.this, args, MainActivity.this);
        }

        @Override
        public void onLoadFinished(@NonNull Loader<Integer> loader, final Integer data) {
            //getSupportLoaderManager().destroyLoader(loader.getId()); //this should fix it but why!!!
            finishCreateNewElement(data);
        }

        @Override
        public void onLoaderReset(@NonNull Loader<Integer> loader) {
            ((SupportInsertLoader) loader).cleanUp();
        }
    };

    private final android.app.LoaderManager.LoaderCallbacks<Integer> mInsertLoaderCallback = new android.app.LoaderManager.LoaderCallbacks<Integer>() {

        @Override
        public android.content.Loader<Integer> onCreateLoader(int id, Bundle args) {
            return new InsertLoader(MainActivity.this, args, MainActivity.this);
        }

        @Override
        public void onLoadFinished(@NonNull android.content.Loader<Integer> loader, final Integer data) {
            finishCreateNewElement(data);
        }

        @Override
        public void onLoaderReset(@NonNull android.content.Loader<Integer> loader) {
            ((InsertLoader) loader).cleanUp();
        }
    };

    private void finishCreateNewElement(Integer data) {
        startActivity(new Intent(this, EditActivity.class).putExtra("R", data));
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case PICK_CODE_SUPPORT:
                if (resultCode == Activity.RESULT_OK && data != null) {
                    getSupportLoaderManager().restartLoader(LOADER_ID, data.getExtras(), mSupportInsertLoaderCallback);
                }
                break;
            case PICK_CODE:
                if (resultCode == Activity.RESULT_OK && data != null) {
                    getLoaderManager().restartLoader(LOADER_ID, data.getExtras(), mInsertLoaderCallback);
                }
                break;
            default:
                super.onActivityResult(requestCode, resultCode, data);
        }
    }

    private Integer createNewElement(Bundle args) {
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return args.getInt("R");
    }

    public static class EditActivity extends AppCompatActivity {
        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            final TextView textView = new TextView(this);
            textView.setText(getIntent().getIntExtra("R", -1) + " was picked \n Now press back!");
            setContentView(textView);
        }
    }


    public static class PickActivity extends AppCompatActivity {
        final static Random rand = new Random();

        @Override
        public void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            final Button button = new Button(this);
            final int retVal = rand.nextInt();
            button.setText("Return picked element: " + retVal);
            button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    setResult(Activity.RESULT_OK, new Intent().putExtra("R", retVal));
                    finish();
                }
            });
            setContentView(button);
        }
    }

    private static class InsertLoader extends android.content.AsyncTaskLoader<Integer> {
        private Bundle args;
        private Integer mInteger = null;
        private MainActivity list;

        InsertLoader(Context context, Bundle args, MainActivity list) {
            super(context);
            this.args = args;
            this.list = list;
        }

        @Override
        public Integer loadInBackground() {
            if (list != null) {
                mInteger = list.createNewElement(args);
                cleanUp();
            }
            return mInteger;
        }

        @Override
        protected void onStartLoading() {
            if (mInteger != null) {
                deliverResult(mInteger);
            }

            if (takeContentChanged() || mInteger == null) {
                forceLoad();
            }
        }

        void cleanUp() {
            list = null;
            args = null;
        }
    }

    private static class SupportInsertLoader extends AsyncTaskLoader<Integer> {
        private Bundle args;
        private Integer mInteger = null;
        private MainActivity list;

        SupportInsertLoader(Context context, Bundle args, MainActivity list) {
            super(context);
            this.args = args;
            this.list = list;
        }

        @Override
        public Integer loadInBackground() {
            if (list != null) {
                mInteger = list.createNewElement(args);
                cleanUp();
            }
            return mInteger;
        }

        @Override
        protected void onStartLoading() {
            if (mInteger != null) {
                deliverResult(mInteger);
            }

            if (takeContentChanged() || mInteger == null) {
                forceLoad();
            }
        }

        void cleanUp() {
            list = null;
            args = null;
        }
    }
}