网络OnMain线程异常 [英] Network OnMain Thread Exception

问题描述

您好。 。



MainActivity.java

Hi. .

MainActivity.java

package com.javapapers.android.form;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;

import com.javapapers.android.form.R;

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class FrmActivity extends Activity {

	Button mButton;
	EditText mEdit;
	TextView mText;
	EditText mDate;

	String id;
	InputStream is;
	String line;
    String result;
    
    
    
	
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_frm);
        mButton = (Button)findViewById(R.id.button1);
        
        mButton.setOnClickListener(new View.OnClickListener() {
        	public void onClick(View view) {
        		mEdit   = (EditText)findViewById(R.id.editText1);
        		mText = (TextView)findViewById(R.id.textView1);
        		id = ((EditText) findViewById(R.id.editText2)).getText().toString();
        		System.out.println(id);
        		select();
        	}
        });
    }
    
    
    public void select()
    {
    	ArrayList<namevaluepair> nameValuePairs = new ArrayList<namevaluepair>();
 
	
	nameValuePairs.add(new BasicNameValuePair("id",id));
    	
    	
		try
    	{
		HttpClient httpclient = new DefaultHttpClient();
	        HttpPost httppost = new HttpPost("http://192.168.1.3/select.php");
	        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
	        HttpResponse response = httpclient.execute(httppost); 
	        HttpEntity entity = response.getEntity();
	        is = entity.getContent();
	        Log.e("pass 1", "connection success ");
	}
        catch(Exception e)
	{
        	Log.e("Fail 1", e.toString());
	    	Toast.makeText(getApplicationContext(), "Invalid IP Address",
			Toast.LENGTH_LONG).show();
	}     
        
  
		try
        {
         	BufferedReader reader = new BufferedReader
				(new InputStreamReader(is,"iso-8859-1"),8);
            	StringBuilder sb = new StringBuilder();
            	
				while ((line = reader.readLine()) != null)
		{
       		    sb.append(line + "\n");
           	}
            	is.close();
            	result = sb.toString();
	        Log.e("pass 2", "connection success ");
	}
        catch(Exception e)
    	{
		Log.e("Fail 2", e.toString());
	}     
       
   	try
    	{
        	JSONObject json_data = new JSONObject(result);
        	String name = (json_data.getString("name"));
		Toast.makeText(getBaseContext(), "Name : "+name,
			Toast.LENGTH_SHORT).show();
    	}
        catch(Exception e)
    	{
        	Log.e("Fail 3", e.toString());
    	}
    }
    
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_frm, menu);
        return true;
    }    
}

activity_main.xml

activity_main.xml

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent" >
 
    <edittext

        android:id="@+id/editText1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="39dp"

        android:padding="11dp"

        android:hint="Id"

        android:ems="10"

        android:inputType="number" >
    </edittext>
    <requestfocus />
 
    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_below="@+id/editText1"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="24dp"

        android:padding="11dp"

        android:text="Select" />
 
</relativelayout>

这是我的代码。 。并显示以下错误

09-06 16：56：09.414：E / Fail 1（7064）：android.os.NetworkOnMainThreadException

09-06 16:56 ：09.424：E / Fail 2（7064）：java.lang.NullPointerException

09-06 16：56：09.434：E / Fail 3（7064）：java.lang.NullPointerException



请任何人解决这个问题。 。

this my code. . and its shows the following error
09-06 16:56:09.414: E/Fail 1(7064): android.os.NetworkOnMainThreadException
09-06 16:56:09.424: E/Fail 2(7064): java.lang.NullPointerException
09-06 16:56:09.434: E/Fail 3(7064): java.lang.NullPointerException

pls anyone resolve this. .

推荐答案

不要在主线程上执行长时间运行操作。网络操作被认为是长时间运行的，如果你尝试这个，框架就会抛出（就像你刚刚经历的那样）。



创建一个 AsyncTask <改为/ code>并将网络代码委托给它。



AsyncTask API文档 [ ^ ]



希望这会有所帮助，

Fredrik

Don't do long running operations on your Main thread. Network operations are considered long running and the framework will throw (like you've just experienced) if you try this.

Create an AsyncTask and delegate the network code to that instead.

AsyncTask API documentation[^]

Hope this helps,
Fredrik

这篇关于网络OnMain线程异常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IT屋！