[英]Problem regarding extending ListActivity
In my project whenever I extend activity it works fine but as soon as I extend ListActivity it throws exception and shows file not found. 在我的项目中,每当我扩展活动时,它都可以正常工作,但只要我扩展ListActivity,就会抛出异常并显示找不到的文件。 Why is that? 这是为什么? We already know that ListActivity itself extends the Activity class. 我们已经知道ListActivity本身扩展了Activity类。 The application must run fine. 应用程序必须正常运行。
Here's the java file: 这是java文件:
package com.android.feedGrabber;
import java.net.URL;
import java.net.URLConnection;
import java.util.Collection;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import com.sun.cnpi.rss.elements.Item;
import com.sun.cnpi.rss.elements.Rss;
import com.sun.cnpi.rss.parser.RssParser;
import com.sun.cnpi.rss.parser.RssParserFactory;
public class feedGrabber extends Activity {
public static Collection<Item> readRSSDocument(String url) throws Exception {
RssParser parser = RssParserFactory.createDefault();
URL feedUrl = new URL(url);
URLConnection urlc=feedUrl.openConnection();
urlc.setRequestProperty("User-Agent","");
urlc.connect();
Rss rss = parser.parse(urlc.getInputStream());
return rss.getChannel().getItems();
}
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
int links=0;
try
{
for(Item item : feedGrabber.readRSSDocument("http://feeds.feedburner.com/Tutorialzine")){
if(links++>3)
break;
TextView t = (TextView)findViewById(R.id.title);
t.append("Title: ");
t.append(item.getTitle().toString());
t.append("\n\n");
//System.out.println("Title: " + item.getTitle());
//System.out.println("Link: " + item.getLink());
}
}catch(Exception e)
{
//
}
}
}
If I change "extends Activity" to "extends ListActivity" it gives the exception. 如果我将“extends Activity”更改为“extends ListActivity”,则会给出异常。 I need to bring this change because I want to implement it on ListView instead of TextView. 我需要进行此更改,因为我想在ListView而不是TextView上实现它。
Error it throws: debug mode gets active and it highlights under Suspended(exception RunTimeException): ActivityThread.performLaunchActivity(ActivityThread$ActivityRecord, Intent) line: 2663. 抛出错误:调试模式变为活动状态,并在Suspended(异常RunTimeException)下突出显示:ActivityThread.performLaunchActivity(ActivityThread $ ActivityRecord,Intent)行:2663。
When you extend a ListActivity, it is expecting the Layout to have a ListView that has an id of "@android:id/list", if you do not have it, it will throw an exception 当您扩展ListActivity时,它期望Layout具有ID为“@android:id / list”的ListView,如果您没有它,它将抛出异常
You layout should look something like this: 你的布局应该是这样的:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
<TextView android:id="@android:id/empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/noresults"/>
</LinearLayout>
没有看到您的main.xml或例外,我不能肯定,但我建议你检查,如果您的列表具有@android:id/list
身份要求 。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.