使用URL的Android项目 [英] Android Project using URL

问题描述

  private   String  getTextFromWWW（字符串 URLin）{
 尝试 {
网址url =  new  URL（URLin）; 
 URLConnection connection = url.openConnection（）; 
 BufferedReader  in  =  new  BufferedReader（ new  InputStreamReader（connection.getInputStream（）））; 
 字符串 text =  in  .readLine（）; 
  in  .close（）; 
 
  return  text; 
 
}  catch （例外e）{
  return   错误> + e.getMessage（）; 
} 
} 

当我调用此方法时，它总是显示错误

错误> null



我分配了权限

 <   uses-permission     android： name   =  android.permission.ACCESS_NETWORK_STATE    /  >  
  <   uses-permission     android：name   =  android.permission.INTERNET    /  >  

直到我从网上读取数据时出现问题...

解决方案

你应该把你的连接代码放入一个线程。试试这个

新线程（新的Runnable（）{
 
 @Override 
 public void run（）{
 // TODO自动生成的方法stub 
 try {
 String URLin =http://www.android.com/; 
 URL url = new URL（URLin）; 
 URLConnection connection = url.openConnection（）; 
 BufferedReader in = new BufferedReader（new InputStreamReader（connection.getInputStream（）））; 
 String text = in.readLine（）; 
 Log.i（ info，text：+ text）; 
 in.close（）; 
 
 return; 
 
} catch（例外e）{
 Log.e（error，Error>+ e.getMessage（））; 
} 
} 
 
}）。start（）; 

private String getTextFromWWW(String URLin) {
   try {
      URL url = new URL(URLin);
      URLConnection connection = url.openConnection();
      BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
      String text = in.readLine();            
      in.close();

      return text;

   } catch (Exception e) {
      return "Error > " + e.getMessage();
   }
}

When I call this method it always shows Error
"Error > null"

I assigned permissions

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />

Till I have problem in reading Data from web...

解决方案

You should put your connection code in a thread. try this

new Thread(new Runnable(){

			@Override
			public void run() {
				// TODO Auto-generated method stub
				try {
					String URLin = "http://www.android.com/";
				      URL url = new URL(URLin);
				      URLConnection connection = url.openConnection();
				      BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
				      String text = in.readLine();    
				      Log.i("info", "text: " + text);
				      in.close();
				 
				      return;
				 
				   } catch (Exception e) {
				      Log.e("error", "Error > " + e.getMessage());
				   }
			}
			
		}).start();

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