Question

这是我的代码，它可以100％运行：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View inflatedView = inflater.inflate(R.layout.t1, container, false);
    final ListView list = (ListView) inflatedView.findViewById(R.id.list);
    class json extends AsyncTask<String,String, List<MovieModel> > {
        ...
        @Override
        protected void onPostExecute(final List<MovieModel> result) {
            ...
            MainActivity.Adapter adapter = new MainActivity.Adapter(getActivity().getApplicationContext(), R.layout.row, result);
            list.setAdapter(adapter);
            list.setOnItemClickListener
            ...
        }
}

但现在我也需要在另一个位置调用json类：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
....
class json .....
 }

@Override
public void onRefresh() {
    new json();// i can't recall in this way, but i need it
}

问题是列表，因为我无法从onCreateView中删除，因为如果我这样做，列表就不会被定义。

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    ....
    new json();
}
class json extends AsyncTask<String,String, List<MovieModel> > {
    ...
    @Override
    protected void onPostExecute(final List<MovieModel> result) {
        ...
        MainActivity.Adapter adapter = new MainActivity.Adapter(getActivity().getApplicationContext(), R.layout.row, result);
        list.setAdapter(adapter);//this is an error now

现在的错误是＆＃34;无法解析simbol＆＃39; list＆＃39;＆＃34;。

Answer 1

快速解决方案是使list成为一个类变量。

public class MainActivty extends Activity {
    private ListView mList;

    private class json extends AsyncTask<String,String, List<MovieModel> > {
        ...
        @Override
        protected void onPostExecute(final List<MovieModel> result) {
        ...
        mList.setAdapter(adapter);
        ...
    }
}

但更好的解决方案是将result从onPostExecute传递回MainActivity以更新用户界面。

public class MainActivty extends Activity {
    private ListView mList;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View inflatedView = inflater.inflate(R.layout.t1, container, false);
        mList = (ListView) inflatedView.findViewById(R.id.list);
        ...
    }

    private void updateUI(final List<MovieModel> result> {
        MainActivity.Adapter adapter 
            = new MainActivity.Adapter(getActivity().getApplicationContext(), R.layout.row, result);
        mList.setAdapter(adapter);
        ...
    }

    private class json extends AsyncTask<String,String, List<MovieModel> > {
        ...
        @Override
        protected void onPostExecute(final List<MovieModel> result) {
        ...
        updateUI(result);
        ...
    }
}

通过这种方式，您可以将AsyncTask和所有用户界面处理中的所有数据处理保留在Activity中。

错误无法使用list.setAdapter（适配器）解析simbol列表

1 个答案: