Question

这是我的第一个异步任务，它首先被调用，它从服务器获取数据，然后onPostExecute执行其他异步任务，下载并设置图像。

private class GetData extends AsyncTask<String, Void, Void> {
    private final HttpClient client = new DefaultHttpClient();
    private String content;
    private String error = null;

    @Override
    protected void onPreExecute() {
    }

    @Override
    protected void onProgressUpdate(Void... progress) {
    }

    @Override
    protected Void doInBackground(String... params) {
        try {
            HttpGet httpget = new HttpGet(params[0]);
            ResponseHandler<String> responseHandler = new BasicResponseHandler();
            content = client.execute(httpget, responseHandler);
        } catch (ClientProtocolException e) {
            error = e.getMessage();
            cancel(true);
        } catch (IOException e) {
            error = e.getMessage();
            cancel(true);
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        if (error == null) {
            try {
                JSONObject dataDishes = new JSONObject(content);
                Log.d("DISHES", dataDishes.toString());

                ArrayList<DishModel> dishData = new ArrayList<DishModel>();
                for (int i = 0; i < 8; i++) {

                    DishModel model = new DishModel();

                    model.setName("Company " + i);
                    model.setDesc("desc" + i);
                    //TODO: set data img
                    new GetImage(model).execute("http://example.com/" + (i + 1) + ".png");
                    dishData.add(model);
                }

                ListView listAllDishes = (ListView) getView().findViewById(R.id.listView);

                DishRowAdapter adapterAllDishes = new DishRowAdapter(getActivity(),
                        R.layout.dish_row, dishData);

                listAllDishes.setAdapter(adapterAllDishes);

            } catch (JSONException e) {
                Log.d("DISHES", e.toString());
            }
        } else {
            Log.e("DISHES", error);
        }
    }
}

这是另一个异步任务，它下载图像，onPostExecute它将图像设置为传递模型。

private class GetImage extends AsyncTask<String, Void, Void> {
    private DishModel model;
    private Bitmap bmp;

    public getImage(DishModel model) {
        this.model = model;
    }

    @Override
    protected void onPreExecute() {
    }

    @Override
    protected void onProgressUpdate(Void... progress) {
    }

    @Override
    protected Void doInBackground(String... params) {
        try {
            URL url = new URL(params[0]);
            Log.d("DISHES", params[0]);
            try {
                bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
            } catch (IOException e) {
                Log.d("DISHES", e.toString());
            }
        } catch (MalformedURLException e) {
            Log.d("DISHES", e.toString());
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        model.setPhoto(bmp);
    }
}

如果我在一个AsyncTask doInBackground(String... params)中同时执行数据/图像下载过程，它就可以工作，但是当我将数据和图像下载拆分成单独的异步任务时，它不起作用。此外，我没有任何例外或错误。

更新：当我切换视图时图像显示..

Answer 1

首先，getImage和getData是类，Java中的类名称是大写的。

从技术上讲，您可以从onProgressUpdate()或onPostExecute() - https://stackoverflow.com/a/5780190/1159507运行另一个AsyncTask 因此，尝试将断点放在第二个AsyncTask调用中，并调用它调用。

将对象模型从其他AsyncTask传递到另一个AsyncTask并将数据添加到模型不会呈现

1 个答案: