Java 调用引发异常的方法
我正在编写一个应用程序来从atom提要中提取和显示内容。该方法是有效的,但当我尝试调用Java 调用引发异常的方法,java,Java,我正在编写一个应用程序来从atom提要中提取和显示内容。该方法是有效的,但当我尝试调用onNavigationItemSelected中的方法“showFeed()”时,会出现错误“Unhandled exception:java.lang.exception” package com.myapp; import java.net.URL; import java.util.Iterator; import com.sun.syndication.feed.synd.SyndEntry; imp
onNavigationItemSelected
中的方法“showFeed()
”时,会出现错误“Unhandled exception:java.lang.exception
”
package com.myapp;
import java.net.URL;
import java.util.Iterator;
import com.sun.syndication.feed.synd.SyndEntry;
import com.sun.syndication.feed.synd.SyndFeed;
import com.sun.syndication.io.SyndFeedInput;
import com.sun.syndication.io.XmlReader;
// ...
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
showFeed();
}
}
// ...
public void showFeed() throws Exception {
URL url = new URL("http://feeds.feedburner.com/javatipsfeed");
XmlReader xmlReader = null;
try {
xmlReader = new XmlReader(url);
SyndFeed feeder = new SyndFeedInput().build(xmlReader);
System.out.println("Title Value " + feeder.getAuthor());
for (Iterator iterator = feeder.getEntries().iterator(); iterator.hasNext();) {
SyndEntry syndEntry = (SyndEntry) iterator.next();
System.out.println(syndEntry.getTitle());
}
} finally {
if (xmlReader != null)
xmlReader.close();
}
}
我想在
onNavigationItemSelected
中调用此方法。您正在UI线程上运行与网络相关的线程,这可能会导致ANR(活动无响应),请遵循以下教程
package com.myapp;
import java.net.URL;
import java.util.Iterator;
import com.sun.syndication.feed.synd.SyndEntry;
import com.sun.syndication.feed.synd.SyndFeed;
import com.sun.syndication.io.SyndFeedInput;
import com.sun.syndication.io.XmlReader;
// ...
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
showFeed();
}
}
// ...
public void showFeed() throws Exception {
URL url = new URL("http://feeds.feedburner.com/javatipsfeed");
XmlReader xmlReader = null;
try {
xmlReader = new XmlReader(url);
SyndFeed feeder = new SyndFeedInput().build(xmlReader);
System.out.println("Title Value " + feeder.getAuthor());
for (Iterator iterator = feeder.getEntries().iterator(); iterator.hasNext();) {
SyndEntry syndEntry = (SyndEntry) iterator.next();
System.out.println(syndEntry.getTitle());
}
} finally {
if (xmlReader != null)
xmlReader.close();
}
}
您的showFeed方法正在引发异常
public void showFeed() throws Exception
这必须使用try catch块捕获,或从调用方方法(即onNavigationItemSelected
所以要么像这样抓住它
case R.id.navigation_home:
try{
showFeed();
} catch (Exception e) {
e.printStackTrace();
}
或者像下面那样再扔一次
public boolean onNavigationItemSelected(@NonNull MenuItem item) throws Exception
例外情况是什么?我猜可能是I/O异常—尝试在单独的线程中写入,或使用异步任务—使用
try catch
或将抛出异常
添加到方法中。检查异常。这消除了错误。谢谢我将此标记为答案,因为它显示了一个示例