android - 从外部访问自定义 ListView 对象

Question

我有一个 ListView，其中的项目包含一个 Button 等等。我从 ListView 的 Adapter 类启动一个 Asynctask:

holder.btn_follow.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {           
        new Follow_Async().execute(arr_id.get(position), arr_name.get(position));
    }

   }
});

这是我的异步任务:

public class Follow_Async extends AsyncTask<String, Void, String> {

        @Override
        protected void onPostExecute(String result) {

//here
            Toast.makeText(Activity_Followers2.this, "You are now following " + result, Toast.LENGTH_SHORT).show();
        }

        @Override
        protected void onPreExecute() { 

        }

        @Override
        protected String doInBackground(String... params) {

            try {
                params_follow = new ArrayList<NameValuePair>();
                params_follow.add(new BasicNameValuePair("session_userid", session_userid));
                params_follow.add(new BasicNameValuePair("friend_userid", params[0]));
                JSONParser jsonParser; jsonParser = new JSONParser();
                JSONObject json = jsonParser.makeHttpRequest(add_follow, "POST", params_follow);
            } catch (Exception e) {
                    e.printStackTrace();
            }
            return params[1];
        }

    }

在 PostExecute() 中，我想将刚刚单击的按钮的文本更改为取消关注。我如何从那里访问它？

Answer 1

只需将您的按钮作为参数传递给 AsyncTask 构造函数:

在适配器中:

final thisButton = holder.btn_follow; // <------------ add a final Button field

thisButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {           
        new Follow_Async(thisButton).   //<------------- pass button to AsyncTask
             execute(arr_id.get(position), arr_name.get(position));
    }
   }
});

在 AsyncTask 中:

class Follow_Async extends AsyncTask<String, Void, String> {

    private final Button button;

    public Follow_Async(Button button) {  //<------------- pass button to constructor
        this.button = button;
    }


    @Override
    protected void onPostExecute(String result) {
        this.button.setText(""); //<--------------- do something with button
    }

}