使用来自互联网的图像更新android小部件(使用异步任务)

我有一个简单的 Android小部件,我想用互联网上的图像更新.我可以在小部件上显示静态图像没问题.我被告知你需要使用异步任务,我对这些没有多少经验.

这是我的小部件：

@Override
    public void onUpdate(Context context,AppWidgetManager appWidgetManager,int[] appWidgetIds) {
 
        super.onUpdate(context,appWidgetManager,appWidgetIds);
 
        for (int i = 0; i < appWidgetIds.length; i++){
            int appWidgetId = appWidgetIds[i];      
 
            RemoteViews views = new RemoteViews(context.getPackageName(),R.layout.activity_main);
 
                //Setup a static image,this works fine.
            views.setImageViewResource(R.id.imageView1,R.drawable.wordpress_icon);             
 
            new DownloadBitmap().execute("MyTestString");       
 
            appWidgetManager.updateAppWidget(appWidgetId,views);
        }

然后我有一个异步任务类来进行下载.它看起来像这样：

public class DownloadBitmap extends AsyncTask<String,Void,Bitmap> {
 
    /** The url from where to download the image. */
    private String url = "http://0.tqn.com/d/webclipart/1/0/5/l/4/floral-icon-5.jpg"; 
 
    @Override
    protected Bitmap doInBackground(String... params) {
        try {
            InputStream in = new java.net.URL(url).openStream();
            Bitmap bitmap = BitmapFactory.decodeStream(in);
            return bitmap;              
            //NOTE:  it is not thread-safe to set the ImageView from inside this method.  It must be done in onPostExecute()
        } catch (Exception e) {
            Log.e("ImageDownload","Download Failed: " + e.getMessage());
        }
        return null;
    }
 
 
    @Override
    protected void onPostExecute(Bitmap bitmap) {
        if (isCancelled()) {
            bitmap = null;
        }
 
           //Here is where I should set the image to the imageview,but how?
    } 
}

我认为我的代码已成功从互联网上下载图像.

我很困惑的是,如何从Async任务类中将此图像放入特定小部件的“ImageView”中.要更新映像,您需要访问3个不同的对象：Context,AppWidgetManager和AppWidgetId ….但是如何在此语句中传递所有这些对象：???

new DownloadBitmap().execute("MyTestString");

谢谢！

解决方法

一种解决方案是将RemoteViews作为参数传递给DownloadBitmap构造函数,并在onPostExecute()中设置图像：

在onUpdate()中：

new DownloadBitmap(views).execute("MyTestString");

并在DownloadBitmap中：

//....
public class DownloadBitmap extends AsyncTask<String,Bitmap> {
    private RemoteViews views;
 
    public DownloadBitmap(RemoteViews views){
        this.views = views;
    }
 
    //.....
    public void onPostExecute(Bitmap bitmap){
        views.setImageViewBitmap(R.id.imageView1,bitmap);
    }
}

使用来自互联网的图像更新android小部件(使用异步任务)

解决方法

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