Question

我正在关注本教程：http://www.codelearn.org/android-tutorial/twitter/10/asynctask-parameters-example

但使用我自己的代码（不做他们的Twitter应用程序）

我似乎无法使openFileOutput工作并尝试将此传递作为参考的组合。

我的类myList通过

调用AsyncFetchData

new AsyncFetchData().execute(this);

我试图用

打开AsyncFetchData中的文件输出

fos = this.openFileOutput(TEA_CACHE_FILE, MODE_PRIVATE);

正如他们在教程中所说的那样。我不能让它工作。至于其余的代码，我只是想创建一个包含虚拟数据的列表，等待是模拟网络调用的延迟。感谢您的帮助，这是我的代码

公共类AsyncFetchData扩展AsyncTask＆lt;列表与LT; TeaDetails＆gt;，Void，Void＆gt; {

private static final String TEA_CACHE_FILE = "tea_cache.ser";
private List<TeaDetails> tempTea = new ArrayList<TeaDetails>();

@Override
protected Void doInBackground(List < TeaDetails > ... params) {

    //while the long job getting done {
    //update progress_data
    //update result
   //}
    try {
        Thread.sleep(5000);
        // create dummy tea list
    }
    catch (Exception e){}
    for (int i=1; i<10; i++){
        TeaDetails tea = new TeaDetails();
        tea.setId("Id is: " + i);
        tea.setTitle("Title for tea number " + i);
        tea.setInfo("Some information about tea "+ i);
        tea.setImgSrc(i);
        tempTea.add(tea);
    }

    FileOutputStream fos;
    ObjectOutputStream oos;
    try {
        //code to write into file
        fos = this.openFileOutput(TEA_CACHE_FILE, MODE_PRIVATE);
        oos = new ObjectOutputStream(fos);
        oos.writeObject(tempTea);
        // show in log that file was successfully written
        Log.d("HelloWorld2", "Successfully wrote teas to the file.");
        //close operators
        oos.close();
        fos.close();

    } catch (Exception e) {
        Log.e("HelloWorld2", "Error writing tweets", e);
    }
    return null;
}

protected void onProgressUpdate(Void... progress_data) {
    //use progress_data to show progress on the screen
}

protected void onPostExecute(Void... result) {
    //use result obtained at the end of
}

}

Answer 1

您正在尝试来自openFileOutput的{{1}}来电，AsyncTask不是Context。而不是

this.openFileOutput(...);

你应该

YourActivity.this.openFileOutput(...);

假设这是一个内部类，否则this引用您的AsyncTask而不是封闭活动。

Android：在AsyncTask中使用openFileOutput

1 个答案: