如何在 BaseAdapter 中完成 Asynctask 后修改单个列表项以

Question

在我的主要 activity 中，我显示了一个 ListView，它使用自定义 BaseAdapter（ThoughtListAdapter）。

listView = (ListView) findViewById(R.id.list);
adapter = new ThoughtListAdapter(this, resultingThoughts);
listView.setAdapter(adapter);

ListView 中的每个项目都有一个自定义布局，其中包含一个 TextView 和两个 Button。

if (convertView == null) {
        convertView = layoutInflater.inflate(R.layout.list_item_thought, null);
}

thoughtText = (TextView) convertView.findViewById(R.id.thought_text_view);
likeButton = (Button) convertView.findViewById(R.id.thought_like_button);
dislikeButton = (Button) convertView.findViewById(R.id.thought_dislike_button);

单击 Button 时，将调用 AsyncTask (AsyncPost)，它连接到我的数据库并进行一些更改。

likeButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            System.out.println("LIKE CLICKED");
            Thought t = thoughtItems.get(position);
            thoughtId = t.getId();
            opinion = 1;

            AsyncPost asyncPost = new AsyncPost(activity,ThoughtListAdapter.this);
            asyncPost.execute(SHARE_THOUGHT_URL,
                    TAG_PERSON_EMAIL, "m@b.it",
                    TAG_THOUGHT_ID, thoughtId.toString(),
                    TAG_OPINION, opinion.toString());
        }
    });

我需要的是在 AsyncTask 完成并获得成功结果后，使列表项的两个 Button-s 消失。我有一个方法 onComplete(JSONObject json)，它详细说明了 AsyncTask 返回的 JSONObject。我尝试使 onComplete 方法中的按钮不可见，但这不起作用，因为 onComplete() 不知道具体单击了哪个按钮。我怎样才能在 onComplete() 中传递精确点击按钮的实例，并使相关列表项的“喜欢”和“不喜欢”按钮消失？

AsyncPost 是我所有其他活动使用的全局 AsyncTask。我强烈希望不要管它。 onComplete() 方法的作用相当于 AsyncTask 的 onPostExecute() 方法。这是我的 BaseAdapter 中的 getView() 和 onComplete() 方法，其中包含上面显示的所有代码。谢谢。

public View getView(final int position, View convertView, ViewGroup parent) {
    if (layoutInflater == null) {
        layoutInflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    if (convertView == null) {
        convertView = layoutInflater.inflate(R.layout.list_item_thought, null);
    }


    thoughtText = (TextView) convertView.findViewById(R.id.thought_text_view);
    likeButton = (Button) convertView.findViewById(R.id.thought_like_button);
    dislikeButton = (Button) convertView.findViewById(R.id.thought_dislike_button);

    //thoughtItems is a list of custom ojbects (Thought)
    Thought t = thoughtItems.get(position);

    //Here i set the content of the current TextView
    thoughtText.setText(t.getText());

    //the two buttons do basically the same thing when get clicked
    likeButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Thought t = thoughtItems.get(position);
            thoughtId = t.getId();
            opinion = 1;

            AsyncPost asyncPost = new AsyncPost(activity,ThoughtListAdapter.this);
            asyncPost.execute(SHARE_THOUGHT_URL,
                    TAG_PERSON_EMAIL, "m@b.it",
                    TAG_THOUGHT_ID, thoughtId.toString(),
                    TAG_OPINION, opinion.toString());
        }
    });

    dislikeButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Thought t = thoughtItems.get(position);
            thoughtId = t.getId();
            opinion = 0;

            AsyncPost asyncPost = new AsyncPost(activity,ThoughtListAdapter.this);
            asyncPost.execute(SHARE_THOUGHT_URL,
                                TAG_PERSON_EMAIL, "m@b.it",
                                TAG_THOUGHT_ID, thoughtId.toString(),
                                TAG_OPINION, opinion.toString());
        }
    });

    return convertView;
}

@Override
public void onComplete(JSONObject json) {
    if (json != null) {
        try {
            if (json.getInt(TAG_SUCCESS) == 0) {
                Toast.makeText(activity, "Operazione non riuscita.", Toast.LENGTH_LONG).show();
            } else {
                //if everything is good i try to make the buttons of that particular list item disappear
                likeButton.setVisibility(View.GONE);
                dislikeButton.setVisibility(View.GONE);
            }
        }
        catch (JSONException e) {
            Log.e(TAG_LOG, "JSONException", e);
        }
    }
    else Toast.makeText(activity, "Errore connessione!", Toast.LENGTH_LONG).show();
}

Answer 1

一个解决方案是在您的 Thought 对象上添加一些东西来指示是否显示按钮。

所以在你的getView()方法中你检查这个

likeButton = (Button) convertView.findViewById(R.id.thought_like_button);
dislikeButton = (Button) convertView.findViewById(R.id.thought_dislike_button);

Thought t = thoughtItems.get(position);
if (t.hideButtons()) {
    likeButton.setVisibility(View.GONE);
    dislikeButton.setVisibility(View.GONE); 
}
else {
    likeButton.setVisibility(View.VISIBLE);
    dislikeButton.setVisibility(View.VISIBLE); 
}

然后你需要让你的 onComplete 方法 return 与它相关的 Thought 对象的 id。然后在你的 onComplete 里面你可以做

int id = //get your id from your JSON response
for(Thought t : thoughtItems) {
    if (t.getId() == id) {
        t.setHideButtons(true);
        notifyDataSetChanged();
        break;
    }
}

通过调用 notifyDataSetChanged()，它会重新绘制您的列表，当它检查是否应该显示按钮时，它不会显示它们，因为它是在那个想法项目上设置的

如何在 BaseAdapter 中完成 Asynctask 后修改单个列表项以

How to modify a single list item after Asynctask is done in a BaseAdapter to

java

android

listview

android-listview

android-asynctask