Android 如何在我的自定义 Listview 中实现 AsyncTask

Question

当我运行我的代码时，我总是得到一个关于 Skipped 303 frames! The application may be doing too much work on its main thread. 如何在下面的代码中实现 AsyncTask，以及如何显示进度条的日志，同时从我的 Parse.com的数据库。如果有任何帮助，我将不胜感激。

这是我的 Activity 的代码：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_doctors_name_list);

    Bundle extras = getIntent().getExtras();
    final String key = extras.getString("KEY");
    ListView lvDoctorsName = (ListView) findViewById(R.id.lvDoctorsName);

    ParseQueryAdapter.QueryFactory<ParseObject> factory = new ParseQueryAdapter.QueryFactory<ParseObject>() {
        public ParseQuery create() {
            ParseQuery query = new ParseQuery("doctors");
            query.whereContains("name", key);
            return query;
        }
    };
    CustomLayout urgentAdapter = new CustomLayout(this, factory);
    lvDoctorsName.setAdapter(urgentAdapter);

    TextView empty = (TextView) findViewById(R.id.empty_list_item);
    lvDoctorsName.setEmptyView(empty);

    itemClickListener();
}

public void itemClickListener() {
    ListView lvDoctorsName = (ListView) findViewById(R.id.lvDoctorsName);
    lvDoctorsName.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            ParseObject item = (ParseObject) parent.getAdapter().getItem(position);
            String objectID = item.getObjectId().toString();
            Intent i = new Intent();
            i.setClass(getApplicationContext(), DoctorPage.class);
            //i.putExtra("new_variable_name",value);
            i.putExtra("objectID", objectID);
            startActivity(i);
        }
    });

}

这是我的自定义布局：

public class CustomLayout extends ParseQueryAdapter<ParseObject> {


public CustomLayout(Context context, QueryFactory<ParseObject> queryFactory) {
    super(context, queryFactory);
}


@Override
public View getItemView(ParseObject object, View v, ViewGroup parent) {
    if (v == null) {
        v = View.inflate(getContext(), R.layout.row, null);
    }
    super.getItemView(object, v, parent);

    TextView titleTextView = (TextView) v.findViewById(R.id.text1);
    titleTextView.setText(object.getString("name"));

    TextView titleTextView2 = (TextView) v.findViewById(R.id.text2);
    titleTextView2.setText(object.getString("city"));

    return v;
}

Answer 1

我看到的一个问题是每次调用 getItemView() 时您都在调用 findViewById()； findViewById() 是一项昂贵的操作。你应该实现类似 ViewHolder 模式的东西来避免这种情况。

Answer 2

根据 Parse 文档的外观，他们会为您处理 AsyncTask。所以这不是问题。

根据您的数据集的大小，Emmanuel findViewById 的回答是正确的。

要回答如何显示进度条，您可以阅读 ParseQueryAdapter 上的文档，它可以让您连接到加载/完成加载触发器。

https://parse.com/docs/android/api/com/parse/ParseQueryAdapter.html

// Perhaps set a callback to be fired upon successful loading of a new set of ParseObjects.
adapter.addOnQueryLoadListener(new OnQueryLoadListener<ParseObject>() {
  public void onLoading() {
    // Trigger any "loading" UI
  }

  public void onLoaded(List<ParseObject> objects, ParseException e) {
    // Execute any post-loading logic, hide "loading" UI
  }
});

Android 如何在我的自定义 Listview 中实现 AsyncTask

Android How to implement AsyncTask in my custom Listview

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parse-platform