java.net.InetAddress.getByName program exit? ?

posts by CCDDzclxy edited 2013-09-17 20:50:53

RT
In " http://www.devdiv.com/Android-_ip_ -thread-52325-1-1.html "in Android found inside the DNS resolution is getByName functions.

However, when I use getByName or getAllByName, procedures are being given directly out of the ...
Please help us to see how the matter? ?

do or say Android inside DNS resolution, not with getByName? That is what is the use? ?

Click the button btnDns when the error directly out of the ...
Error in Figure:


The following code is run on a virtual machine (xp + eclipse):

 

import android.os.Bundle; 
import android.app.Activity; 
import android.view.Menu; 

import android.graphics.Color; 
import android.view.View; 
import android.widget.Button; 
import android.widget.TextView; 
import android.widget.EditText; 
import java.net *;. 

public class MainActivity extends Activity 
{
public EditText etMsg; 

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

/ / *** 

etMsg = (EditText) findViewById (R.id.etMsg); 
Button btnDns = (Button) findViewById (R.id.btnDns); 
btnDns.setOnClickListener (new Button.OnClickListener () 
{
@ Override 
public void onClick (View v) 
{
try 
{
InetAddress x = InetAddress.getByName ("www.baidu.com"); 
} 
catch (Exception e) 
{
etMsg.append (e.getMessage ()); 
} 
} 
}); 

} 

@ Override 
public boolean onCreateOptionsMenu (Menu menu) {
/ / Inflate the menu; this adds items to the action bar if it is present 
.getMenuInflater () inflate (R.menu.main, menu);. 
return true; 
} 

} 

Please help, thank you.

<-! Baidu Button BEGIN -> more Share to: <-! Baidu Button END ->

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Reply:
You should not look at logcat exception information inside the country. Should be the question of powers. You see is not.
Reply:

cited a floor Jia_H reply:

you do not see logcat exception information inside the country. Should be the question of powers. You see is not.

Novice, do not understand ... that there seems to be a null pointer exception? ?
Reply:

cited a floor Jia_H reply:

you do not see logcat exception information inside the country. Should be the question of powers. You see is not.

Permission to do so, whether it is to say this:
I have added the following two sentences in AndroidManifest.xml inside:


Reply:
Yeah, debug it. Which shows that one out in append a null reference exception.

Description:
An error occurred while a call getName, should be the question of powers just said, you need to add access to the network in the xml file permissions
2 Check that etmsg id and xml inside are the same
Reply:

references, 4th Floor Jia_H reply:

Yeah, debug it. Which shows that one out in append a null reference exception.

Description:
An error occurred while a call getName, should be the question of powers just said, you need to add access to the network in the xml file permissions
2 Check that etmsg id and xml inside are the same

Indeed, I etMsg.append (e.getMessage ()); into etMsg.append ("err"); had "err" is displayed, it shows getByName wrong ah, yes permissions problem? ? I added two lines of code on the 3rd floor, ah ...
Reply:
I changed:

 
catch (Exception e) 
{
String strErr = e.getMessage (); 
etMsg.append ("err:" + strErr); 
} 

Will print out: "err: null". This shows that description? ? ? ...
Reply:
I added a:

 
android: id = "@ + id/textView1" 
android: layout_width = "wrap_content" 
android: layout_height = "wrap_content" 
android: layout_below = "@ + id / btnDns" 
android: layout_marginTop = "14dp" 
android: autoLink = "all" 
android: text = "http://www.baidu.com/" /> 

Click the link, the page can be opened baidu should have access permissions explain it ...
Reply:
Is e.getMessage () returns null, and a bit strange. With e.printTraceStack output to see if there can be referenced content.
Reply:

reference to the 8th floor Jia_H reply:

is e.getMessage () returns null, and a bit strange. With e.printTraceStack output to see if there can be referenced content.

Into this:

 
catch (Exception e) 
{
/ / EtMsg.append (e.getMessage ()); / / directly so wrong ... 
String strErr = e.getMessage (); 
etMsg.append ("err:" + strErr + "\ r \ n"); 

StringWriter sw = new StringWriter (); 
PrintWriter pw = new PrintWriter (sw); 
e.printStackTrace (pw); 
/ / System.out.println (sw.toString () toUpperCase ().); 
etMsg.append (sw.toString () toUpperCase ().); 
} 

Output information:
(Not to fetch the files inside the virtual machine ... only print out, cut a four figure ... I saw did not understand what the problem ...)




Reply:
Found, is NetworkOnMainThreadException, the main thread can not restrict access to the network:
http://www.eoeandroid.com/thread-272038-1-1.html
Reply:
Yes, forget this crop up.