问题描述
好的,我投降了.我无法弄清楚.
Okay, I surrender. I cannot figure it out.
我正在学习有关Android Basics的Udacity课程,并且需要弄清楚如何使用Loader加载数据.但是,当我使用以下行时,"this"以红色突出显示并显示以下错误:
I'm following a Udacity course on Android Basics and need to figure out how to load data using a Loader. However, when I use the following line, the 'this' is highlighted in red and showing the following error:
Wrong 3rd argument type. Found 'com.example.carl.latestnews.MainActivity', required: 'android.app.LoaderManager.LoaderCallbacks<java.lang.Object>
我已经搜索,堆积并尝试了我发现的建议.我尝试创建一个实现回调的内部类.我碰到了砖墙,我坐在这里挠头试图找出我所缺少的!
I've googled, stacked and tried suggestion I've found. I've tried creating an inner class which implements the call backs. I've hit a brickwall and I'm sat here scratching my head trying to figure out what I'm missing!
有人可以告诉我我在做什么错吗?
Can anyone tell me what I'm doing wrong here?
提前谢谢!
package com.example.carl.latestnews;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.AsyncTaskLoader;
import android.support.v4.content.Loader;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<ArrayList<ArticleObject>> {
// ArticleObject is a custom object which contains a headline, date, category etc of a news article
// URL for Guardian API including API Key
final static String GUARDIAN_API_URL = "https://content.guardianapis.com/search?";
// API Key
final static String GUARDIAN_API_KEY = "test";
// ID for LoaderManager
final static int LOADER_MANAGER_ID = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Get or initialize loader manager
getLoaderManager().initLoader(LOADER_MANAGER_ID, null, this);
}
@Override
public Loader<ArrayList<ArticleObject>> onCreateLoader(int id, Bundle args) {
return new dataLoader(); // dataLoader() removed for easy reading
}
@Override
public void onLoadFinished(Loader<ArrayList<ArticleObject>> loader, ArrayList<ArticleObject> data) {
/ UI Update Code
}
@Override
public void onLoaderReset(Loader<ArrayList<ArticleObject>> loader) {
// Reset Code
}
}
推荐答案
该方法期望LoaderCallbacks作为参数.
That method expects LoaderCallbacks as an argument.
您的活动需要实现 LoaderCallbacks接口.或者您提供该接口的匿名实现,例如:
Your Activity needs to implement the LoaderCallbacks interface.ORyou provide an anonymous implementation of that interface like:
LoaderManager.LoaderCallbacks callbacks = new LoaderManager.LoaderCallbacks() {
@Override
public Loader onCreateLoader(int id, Bundle args) {
return null;
}
@Override
public void onLoadFinished(Loader loader, Object data) {
}
@Override
public void onLoaderReset(Loader loader) {
}
getLoaderManager().initLoader(LOADER_MANAGER_ID, null, callback);
不过接口方法的实现取决于您,此代码无法立即起作用.
Implementation of the interface methods is up to you though, this code won't work right away.
这篇关于LoaderManager不接受“此"的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!