java - 加载通知图像的最佳方式？

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加载通知图像的最佳方式是什么？

这是我目前的方式:如您所见，图像同步加载，因此通知可能会延迟。这是一个不好的方法。

public Bitmap getBitmapFromURL(String strURL) {
    try {
        URL url = new URL(strURL);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setDoInput(true);
        connection.connect();
        InputStream input = connection.getInputStream();
        Bitmap myBitmap = BitmapFactory.decodeStream(input);
        return myBitmap;
    } catch (IOException e) {
        e.printStackTrace();
        return null;
    }
}

Bitmap bitmap = getBitmapFromURL("https://graph.facebook.com/YOUR_USER_ID/picture?type=large");

// CONSTRUCT THE NOTIFICATION DETAILS
builder.setAutoCancel(true);
builder.setSmallIcon(R.drawable.ic_launcher);
builder.setContentTitle("Some Title");
builder.setContentText("Some Content Text");
builder.setLargeIcon(bitmap);
builder.setContentIntent(pendingIntent);

我真的需要一个答案来继续我的项目。

Answer 1

您应该首先通知没有图像或占位符的通知，然后使用 AsyncTask 加载位图，或使用 Picasso 和 Target 回调。

将您用于第一次通知的构建器提供给您的任务，当加载位图时，将其添加到构建器中，然后重新通知您的通知。

如果在完整的图像加载之前内容已更改的风险，请存储一个变量来标识您要显示的当前内容，您可以在重新通知之前检查该变量。

您可以按照 google UniversalMusicPlayer 提供的 MediaNotificationManager 示例进行操作项目。

在你的情况下:

// CONSTRUCT THE NOTIFICATION DETAILS
builder.setAutoCancel(true);
builder.setSmallIcon(R.drawable.ic_launcher);
builder.setContentTitle("Some Title");
builder.setContentText("Some Content Text");
//builder.setLargeIcon(bitmap); // replace this line with place holder drawable from resources
builder.setContentIntent(pendingIntent);

manager.notify(NOTIFICATION_ID, builder.build());

currentLoadImageTask = new LoadImageTask(manager, builder);
currentLoadImageTask.execute("https://graph.facebook.com/YOUR_USER_ID/picture?type=large");

// ...

static class LoadImageTask extends AsyncTask<String, Void, Bitmap> {

    final NotificationManager manager;
    final NotificationCompat.Builder builder;

    public LoadImageTask(final NotificationManager manager, final NotificationCompat.Builder builder) {
        this.manager = manager;
        this.builder = builder;
    }

    @Override
    protected Bitmap doInBackground(final String... strings) {
        if (strings == null || strings.length == 0) {
            return null;
        }
        try {
            final URL url = new URL(strings[0]);
            final HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput(true);
            connection.connect();
            final InputStream input = connection.getInputStream();
            return BitmapFactory.decodeStream(input);
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    @Override
    protected void onPostExecute(final Bitmap bitmap) {
        if (bitmap == null || manager == null || builder == null) {
            return;
        }
        builder.setLargeIcon(bitmap);
        manager.notify(NOTIFICATION_ID, builder.build());
    }
}

毕加索:

// CONSTRUCT THE NOTIFICATION DETAILS
builder.setAutoCancel(true);
builder.setSmallIcon(R.drawable.ic_launcher);
builder.setContentTitle("Some Title");
builder.setContentText("Some Content Text");
//builder.setLargeIcon(bitmap); // replace this line with place holder drawable from resources
builder.setContentIntent(pendingIntent);

manager.notify(NOTIFICATION_ID, builder.build());

// ...

Picasso.with(context)
    .load("https://graph.facebook.com/YOUR_USER_ID/picture?type=large")
    .resize(250, 250)
    .into(new Target() {
        @Override
        public void onBitmapLoaded(final Bitmap bitmap, final Picasso.LoadedFrom from) {
            builder.setLargeIcon(bitmap);
            manager.notify(NOTIFICATION_ID, builder.build());
        }

        @Override
        public void onBitmapFailed(final Drawable errorDrawable) {
             // Do nothing
        }

        @Override
        public void onPrepareLoad(final Drawable placeHolderDrawable) {
             // Do nothing
        }
    });

如果不在 UiThread 中，您可以创建一个 Runnable 并在 Looper 中执行它

 final Handler uiHandler = new Handler(Looper.getMainLooper());
 uiHandler.post(new Runnable() {
      @Override
      public void run() {
           // Call from here
      }
 });

毕加索要好得多，仅仅是因为使用了缓存。

我强烈建议您调整在通知中设置的每个位图的大小，因为如果您不这样做，它很容易引发 OutOfMemoryException。