LocationMapFragment.java

/*
 * Copyright (C) 2012 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.squareup.otto.sample;

import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import com.squareup.otto.Subscribe;

import java.net.URL;

import static android.widget.ImageView.ScaleType.CENTER_INSIDE;

/** Display a map centered on the last known location. */
public class LocationMapFragment extends Fragment {
  private static final String URL =
      "https://maps.googleapis.com/maps/api/staticmap?sensor=false&size=400x400&zoom=13¢er=%s,%s";
  private static DownloadTask downloadTask;

  private ImageView imageView;

  @Override public void onResume() {
    super.onResume();
    BusProvider.getInstance().register(this);
  }

  @Override public void onPause() {
    super.onPause();
    BusProvider.getInstance().unregister(this);

    // Stop existing download, if it exists.
    if (downloadTask != null) {
      downloadTask.cancel(true);
      downloadTask = null;
    }
  }

  @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    imageView = new ImageView(getActivity());
    imageView.setScaleType(CENTER_INSIDE);
    return imageView;
  }

  @Subscribe public void onLocationChanged(LocationChangedEvent event) {
    // Stop existing download, if it exists.
    if (downloadTask != null) {
      downloadTask.cancel(true);
    }

    // Trigger a background download of an image for the new location.
    downloadTask = new DownloadTask();
    downloadTask.execute(String.format(URL, event.lat, event.lon));
  }

  @Subscribe public void onImageAvailable(ImageAvailableEvent event) {
    if (imageView != null) {
      imageView.setImageDrawable(event.image);
    }
  }

  private static class ImageAvailableEvent {
    public final Drawable image;

    ImageAvailableEvent(Drawable image) {
      this.image = image;
    }
  }

  private static class DownloadTask extends AsyncTask<String, Void, Drawable> {
    @Override protected Drawable doInBackground(String... params) {
      try {
        return BitmapDrawable.createFromStream(new URL(params[0]).openStream(), "bitmap.jpg");
      } catch (Exception e) {
        Log.e("LocationMapFragment", "Unable to download image.", e);
        return null;
      }
    }

    @Override protected void onPostExecute(Drawable drawable) {
      if (!isCancelled() && drawable != null) {
        BusProvider.getInstance().post(new ImageAvailableEvent(drawable));
      }
    }
  }
}