Question

如何在UI中设置图像，从另一个运行asynctask的类中获取图像（位图）？我认为我可以使用AsyncTask.get（）在线程完成时在UI中执行某些操作，但我认为这不是最好的方法，这里是Activity的代码和要下载图像的类：

public class Recipe extends Activity {
    private ImageView image;
    private static final String baseURL = "http://x/images/";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.recipe_activity);

        Intent i = getIntent();
        GetRecipe getR = new GetRecipe(i.getStringExtra("id"));
        getR.getId();

        TextView title = (TextView) findViewById(R.id.tvRecipeTitle);
        title.setText(getR.getName());
        TextView description = (TextView) findViewById(R.id.tvRecipeDescription);
        description.setText(getR.getDescription());
        String imageURL = getR.getImage();

        Log.d("Recipe", "setting image");
        image = (ImageView) findViewById(R.id.ivRecipe);
        Log.d("Recipe", "Image url: " + imageURL);

        // Download image
        GetRecipeImage GRI = new GetRecipeImage(baseURL + imageURL, this);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.recipe, menu);
        return true;
    }

    // This method should be called when image is full downloaded
    public void setImageView(Bitmap bp) {
        image.setImageBitmap(bp);
    }

}


public class GetRecipeImage {
    private Context context;
    private String url;

    // private Bitmap downloadedImage = null;
    // private AsyncTask<Void, Void, Void> GIAsyncTask;

    public GetRecipeImage(String url, Context context) {
        this.context = context;
        this.url = url;
        new DownloadImageTask().execute();
    }

    public static Bitmap getBitmapFromAsset(Context con) {
        AssetManager assetManager = con.getAssets();

        InputStream istr;
        Bitmap bitmap = null;
        try {
            istr = assetManager.open("imagenotfound.png");
            bitmap = BitmapFactory.decodeStream(istr);
        } catch (IOException e) {
            return null;
        }

        return bitmap;
    }

    private Bitmap imageNotFound() {
        return getBitmapFromAsset(context);
    }

    private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {

        protected Bitmap doInBackground(String... urls) {

            Log.d("GRI", "getting image");
            String urldisplay = urls[0];
            Bitmap mIcon11 = null;
            try {
                InputStream in = new java.net.URL(urldisplay).openStream();
                mIcon11 = BitmapFactory.decodeStream(in);
            } catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            if (mIcon11 == null) {
                return imageNotFound();

            } else {
                return mIcon11;
            }

        }

        protected void onPostExecute(Bitmap result) {

            // context.getClass().getSimpleName().setImageView();
        }
    }
}

感谢您的关注！

Answer 1

为什么在AsyncTask已经是内部类的情况下获取上下文？

只需拨打Recipe.this ..

即可调用您班级的方法

protected void onPostExecute(Bitmap result) {

          Recipe.this.setImageView(result);
}

使用Asynctask从另一个类设置UI的imageview？

1 个答案: