com.zapek.android.workerfragment.WorkerFragment.java Source code

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Here is the source code for com.zapek.android.workerfragment.WorkerFragment.java

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/*
 * Created by David Gerber <dg@zapek.com>
 * 
 * Copyright (c) 2013 by David Gerber
 * All Rights Reserved
 * 
 * This file is WTFPL (see LICENSE file). Just copy it into your
 * project and you're done.
 */
package com.zapek.android.workerfragment;

import java.util.ArrayList;

import android.app.Activity;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.ResultReceiver;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;

/**
 * Invisible {@link Fragment} used to persist some work and not miss the result
 * even when the {@link Activity} is recreated (for example during a
 * Configuration Change).
 * 
 * @author David Gerber
 */
public class WorkerFragment extends Fragment {

    private static final String TAG = "worker";

    public static final int RESULTCODE_HELLOWORLD = 1; /* this is used by the example */

    /* add additional result codes here */

    public interface WorkerFragmentReceiver {
        public void onReceiveResult(int resultCode, Bundle resultData);
    }

    private class Result {
        private final int resultCode;
        private final Bundle resultData;

        private Result(int resultCode, Bundle resultData) {
            this.resultCode = resultCode;
            this.resultData = resultData;
        }
    }

    private static final String KEY_RECEIVER = "receiver";

    private final ArrayList<Result> results = new ArrayList<Result>();
    private final FragmentResultReceiver receiver;

    private class FragmentResultReceiver extends ResultReceiver {

        private boolean enabled;

        private FragmentResultReceiver(Handler handler) {
            super(handler);
        }

        @Override
        protected void onReceiveResult(int resultCode, Bundle resultData) {
            if (this.enabled) {
                WorkerFragment.this.onReceiveResult(resultCode, resultData);
            }
        }

        private void setEnabled(boolean enabled) {
            this.enabled = enabled;
        }
    }

    /**
     * Get the WorkerFragment. This is to be called on your
     * {@link Activity#onCreate} method at all times.
     * 
     * @param fragmentManager
     *            {@link FragmentManager} of the {@link Activity}
     * @return the WorkerFragment
     */
    public static WorkerFragment getWorkerFragment(FragmentManager fragmentManager) {
        WorkerFragment workerFragment = (WorkerFragment) fragmentManager.findFragmentByTag(TAG);
        if (workerFragment == null) {
            workerFragment = new WorkerFragment();
            fragmentManager.beginTransaction().add(workerFragment, TAG).commit();
        }
        return (workerFragment);
    }

    public WorkerFragment() {
        super();
        this.receiver = new FragmentResultReceiver(new Handler());
        this.receiver.setEnabled(true);
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setRetainInstance(true);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        Activity activity = this.getActivity();

        for (Result result : this.results) {
            this.handleResult(activity, result.resultCode, result.resultData);
        }
        this.results.clear();
    }

    @Override
    public void onDestroy() {
        this.receiver.setEnabled(false);
        super.onDestroy();
    }

    private void onReceiveResult(int resultCode, Bundle resultData) {
        Activity activity = this.getActivity();
        if (activity != null) {
            this.handleResult(activity, resultCode, resultData);
        } else {
            this.results.add(new Result(resultCode, resultData));
        }
    }

    /**
     * To be called on the {@link Intent} to pass to
     * {@link Context#startService}.
     * 
     * @param intent
     *            {@link Intent} to send to the service
     */
    public void putReceiver(Intent intent) {
        intent.putExtra(KEY_RECEIVER, this.receiver);
    }

    /**
     * Get the {@link ResultReceiver}.
     * 
     * @return the {@link ResultReceiver}
     */
    public ResultReceiver getReceiver() {
        return (this.receiver);
    }

    /**
     * To be called by the {@link Service} to send the result back to the
     * {@link Activity}.
     * 
     * @param intent
     *            {@link Intent} that the {@link Service} received.
     * @param resultCode
     *            the result code, used to differentiate what command this
     *            result belongs to
     * @param result
     *            the {@link Bundle} which contains the data you're interested
     *            in
     */
    public static void sendResult(Intent intent, int resultCode, Bundle result) {
        ResultReceiver receiver = intent.getParcelableExtra(KEY_RECEIVER);
        receiver.send(resultCode, result);
    }

    private void handleResult(Activity activity, int resultCode, Bundle resultData) {
        WorkerFragmentReceiver receiver = null;
        try {
            receiver = (WorkerFragmentReceiver) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString() + " must implement WorkerFragmentReceiver");
        }
        receiver.onReceiveResult(resultCode, resultData);
    }
}