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android.os.NetworkOnMainThreadException

程序员文章站 2022-05-31 14:28:56
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如果不想看请点击解决问题该最简单的方法

使用android测试访问web服务器的webservice时，在MainActivity的主线程中访问webservice,代码如下：

package com.example.myandroidpro;
 
import java.io.File;
 
import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
 
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.os.StrictMode;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
 
public class MainActivity extends Activity {
 
    private static String NAMESPACE = "http://service.cxf.test/";
    // webService地址
    private static String URL = "http://192.168.1.119:8080/CxfWebService/services/HelloService/";
 
    private String method_name = null;
    private Button activity_main_btn1;
 
    @SuppressLint("NewApi") @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        StrictMode.ThreadPolicy policy=new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        
        File rootDirectory = Environment.getRootDirectory();//获取手机根目录
        File storageDirectory = Environment.getExternalStorageDirectory();//获取SD卡根目录
 
        for(File file : rootDirectory.listFiles()){
            System.err.println(file.isDirectory()+","+file.getName());
        } 
        
        findVIew();
        
        activity_main_btn1.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View arg0) {
                //发送webservice请求
                    sayHi("zxn");    
            }
        });
        
    }
 
    private void findVIew() {
        activity_main_btn1 = (Button) findViewById(R.id.activity_main_btn1);
 
    }
 
    private String sayHi(String name) {
        String result = null;
        // （1） 指定webservice的命名空间和调用的方法名
        method_name = "sayHi";
        SoapObject soapObj = new SoapObject(NAMESPACE, method_name);
        /**
         * （2） 设置调用方法的参数值，如果没有参数，可以省略。 要注意的是，参数必须和服务声明的@WebParam里面的变量名对应
         */
        soapObj.addProperty("name", name);
        // （3） 生成调用Webservice方法的SOAP请求信息。该信息由SoapSerializationEnvelope对象描述
        SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(
                SoapEnvelope.VER11);
        // envelope.bodyOut = rpc;
        envelope.dotNet = false;
        envelope.setOutputSoapObject(soapObj);
        // （4）创建HttpTransportsSE对象。通过AndroidHttpTransport类的构造方法可以指定WebService的WSDL文档的URL
        HttpTransportSE ht = new HttpTransportSE(URL);
        try {
            // (5)使用call方法调用WebService方法
            ht.call(null, envelope);
            // （6）使用getResponse方法获得WebService方法的返回结果
            if (envelope.getResponse() != null) {
                System.out.println(envelope.getResponse());
                result = String.valueOf(envelope.getResponse());
                Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT)
                        .show();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
 
}

由于在主线程中访问网络，android版本为4.3，导致如下异常：

<span style="background-color: rgb(255, 204, 255);">05-15 02:00:05.769: W/System.err(2269): android.os.NetworkOnMainThreadException
05-15 02:00:05.799: W/System.err(2269): 	at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1133)</span>
05-15 02:00:05.799: W/System.err(2269): 	at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
05-15 02:00:05.810: W/System.err(2269): 	at libcore.io.IoBridge.connectErrno(IoBridge.java:144)
05-15 02:00:05.810: W/System.err(2269): 	at libcore.io.IoBridge.connect(IoBridge.java:112)
05-15 02:00:05.869: D/dalvikvm(2269): GC_FOR_ALLOC freed 345K, 14% free 2674K/3076K, paused 48ms, total 52ms
05-15 02:00:05.869: W/System.err(2269): 	at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
05-15 02:00:05.880: W/System.err(2269): 	at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
05-15 02:00:05.880: W/System.err(2269): 	at java.net.Socket.connect(Socket.java:842)
05-15 02:00:05.889: W/System.err(2269): 	at libcore.net.http.HttpConnection.<init>(HttpConnection.java:76)
05-15 02:00:05.889: W/System.err(2269): 	at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
05-15 02:00:05.899: W/System.err(2269): 	at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
05-15 02:00:05.899: W/System.err(2269): 	at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
05-15 02:00:05.899: W/System.err(2269): 	at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
05-15 02:00:05.899: W/System.err(2269): 	at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316)
05-15 02:00:05.899: W/System.err(2269): 	at libcore.net.http.HttpEngine.connect(HttpEngine.java:311)
05-15 02:00:05.909: W/System.err(2269): 	at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290)
05-15 02:00:05.909: W/System.err(2269): 	at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240)
05-15 02:00:05.909: W/System.err(2269): 	at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:81)
05-15 02:00:05.909: W/System.err(2269): 	at libcore.net.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:197)
05-15 02:00:05.919: W/System.err(2269): 	at org.ksoap2.transport.ServiceConnectionSE.openOutputStream(ServiceConnectionSE.java:126)
05-15 02:00:05.919: W/System.err(2269): 	at org.ksoap2.transport.HttpTransportSE.call(HttpTransportSE.java:185)
05-15 02:00:05.929: W/System.err(2269): 	at org.ksoap2.transport.HttpTransportSE.call(HttpTransportSE.java:118)
05-15 02:00:05.929: W/System.err(2269): 	at org.ksoap2.transport.HttpTransportSE.call(HttpTransportSE.java:113)
05-15 02:00:05.969: W/System.err(2269): 	at com.example.myandroidpro.MainActivity.sayHi(MainActivity.java:77)
05-15 02:00:05.969: W/System.err(2269): 	at com.example.myandroidpro.MainActivity.access$0(MainActivity.java:58)
05-15 02:00:05.969: W/System.err(2269): 	at com.example.myandroidpro.MainActivity$1.onClick(MainActivity.java:47)
05-15 02:00:05.969: W/System.err(2269): 	at android.view.View.performClick(View.java:4240)
05-15 02:00:05.979: W/System.err(2269): 	at android.view.View$PerformClick.run(View.java:17721)
05-15 02:00:05.979: W/System.err(2269): 	at android.os.Handler.handleCallback(Handler.java:730)
05-15 02:00:06.012: W/System.err(2269): 	at android.os.Handler.dispatchMessage(Handler.java:92)
05-15 02:00:06.012: W/System.err(2269): 	at android.os.Looper.loop(Looper.java:137)
05-15 02:00:06.019: W/System.err(2269): 	at android.app.ActivityThread.main(ActivityThread.java:5103)
05-15 02:00:06.019: W/System.err(2269): 	at java.lang.reflect.Method.invokeNative(Native Method)
05-15 02:00:06.019: W/System.err(2269): 	at java.lang.reflect.Method.invoke(Method.java:525)
05-15 02:00:06.034: W/System.err(2269): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
05-15 02:00:06.034: W/System.err(2269): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
05-15 02:00:06.039: W/System.err(2269): 	at dalvik.system.NativeStart.main(Native Method)

原因：

android.os.NetworkOnMainThreadException是说不要在主线程中访问网络，这个是android3.0版本开始就强制程序不能在主线程中访问网络，要把访问网络放在独立的线程中。

解决：

在开发中，为了防止访问网络阻塞主线程，一般都要把访问网络放在独立线程中或者异步线程AsyncTask中。

先在AndroidManifest.xml文件manifest节点中添加如下配置：
<uses-permission android:name="android.permission.INTERNET"/>

  1. 想要忽略这些强制策略问题的话，可以在onCreate()方法里面加上
    @SuppressLint("NewApi")
StrictMode.ThreadPolicy policy=new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

  2. 将网络访问放到单独线程中：

    package com.example.myandroidpro;
 
import java.io.File;
 
import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
 
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.StrictMode;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
 
public class MainActivity extends Activity {
 
	private static String NAMESPACE = "http://service.cxf.test/";
	// webService地址
	private static String URL = "http://192.168.1.119:8080/CxfWebService/services/HelloService/";
 
	private String method_name = null;
	private Button activity_main_btn1;
 
	private int ANDROID_ACCESS_CXF_WEBSERVICES = 001; 
	
	
	private Handler handler = new Handler(){
		@Override
		public void handleMessage(Message msg) {
			String result = (String) msg.getData().get("result");
			String obj = (String) msg.obj;//
			activity_main_btn1.setText("请求结果为："+result);
		}
		
	};
	
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        File rootDirectory = Environment.getRootDirectory();//获取手机根目录
        File storageDirectory = Environment.getExternalStorageDirectory();//获取SD卡根目录
 
        for(File file : rootDirectory.listFiles()){
        	System.err.println(file.isDirectory()+","+file.getName());
        } 
        
        findVIew();
        
        activity_main_btn1.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View view) {
				Thread accessWebServiceThread = new Thread(new WebServiceHandler());
				accessWebServiceThread.start();
				
			}
		});
        
    }
 
    class WebServiceHandler implements Runnable{
		@Override
		public void run() {
			Looper.prepare();
			String result = sayHi("zxn");
			Message message = new Message();
			Bundle bundle = new Bundle();
			bundle.putString("result", result);
			message.what = ANDROID_ACCESS_CXF_WEBSERVICES;//设置消息标示
			message.obj = "zxn";
			message. setData(bundle);//消息内容
			handler.sendMessage(message);//发送消息
			Looper.loop();
		}
    	
    }
    
	private void findVIew() {
		activity_main_btn1 = (Button) findViewById(R.id.activity_main_btn1);
 
	}
 
	private String sayHi(String name) {
		String result = null;
		// （1） 指定webservice的命名空间和调用的方法名
		method_name = "sayHi";
		SoapObject soapObj = new SoapObject(NAMESPACE, method_name);
		/**
		 * （2） 设置调用方法的参数值，如果没有参数，可以省略。 要注意的是，参数必须和服务声明的@WebParam里面的变量名对应
		 */
		soapObj.addProperty("name", name);
		// （3） 生成调用Webservice方法的SOAP请求信息。该信息由SoapSerializationEnvelope对象描述
		SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(
				SoapEnvelope.VER11);
		// envelope.bodyOut = rpc;
		envelope.dotNet = false;
		envelope.setOutputSoapObject(soapObj);
		// （4）创建HttpTransportsSE对象。通过AndroidHttpTransport类的构造方法可以指定WebService的WSDL文档的URL
		HttpTransportSE ht = new HttpTransportSE(URL);
		try {
			// (5)使用call方法调用WebService方法
			ht.call(null, envelope);
			// （6）使用getResponse方法获得WebService方法的返回结果
			if (envelope.getResponse() != null) {
				System.out.println(envelope.getResponse());
				result = String.valueOf(envelope.getResponse());
				Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT)
						.show();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return result;
	}
 
}

    MainActivity的相应布局如下：

    <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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >
 
    <LinearLayout android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical">
        <TextView
            android:id="@+id/activity_main_tv1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/hello_world" />
 
        <Button
            android:id="@+id/activity_main_btn1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/test_for_cxf_webservice" />
    </LinearLayout>
</RelativeLayout>

  3. 将网络访问放到异步任务AsyncTask中，代码如下：

    package com.example.myandroidpro;
 
import java.io.File;
 
import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
 
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
 
public class MainActivity extends Activity {
 
	private static String NAMESPACE = "http://service.cxf.test/";
	// webService地址
	private static String URL = "http://192.168.1.119:8080/CxfWebService/services/HelloService/";
 
	private String method_name = null;
	private Button activity_main_btn1;
 
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        File rootDirectory = Environment.getRootDirectory();//获取手机根目录
        File storageDirectory = Environment.getExternalStorageDirectory();//获取SD卡根目录
 
        for(File file : rootDirectory.listFiles()){
        	System.err.println(file.isDirectory()+","+file.getName());
        } 
        
        findVIew();
        
        activity_main_btn1.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View view) {
				accessWSAction();
			}
 
			private void accessWSAction() {
				new AsyncTask<String, Void, Object>() {
					
					//在doInBackground 执行完成后，onPostExecute 方法将被UI 线程调用，
					// 后台的计算结果将通过该方法传递到UI 线程，并且在界面上展示给用户.
					protected void onPostExecute(Object result) {
						super.onPostExecute(result);
						activity_main_btn1.setText("请求结果为："+result);//可以更新UI
					}
 
					//该方法运行在后台线程中，因此不能在该线程中更新UI，UI线程为主线程
					protected Object doInBackground(String... params) {
						String result = sayHi("zxn");
//						activity_main_btn1.setText("请求结果为："+result);
						return result;
					}
 
				}.execute();
				
			}
		});
    }
 
	private void findVIew() {
		activity_main_btn1 = (Button) findViewById(R.id.activity_main_btn1);
 
	}
 
	private String sayHi(String name) {
		String result = null;
		// （1） 指定webservice的命名空间和调用的方法名
		method_name = "sayHi";
		SoapObject soapObj = new SoapObject(NAMESPACE, method_name);
		/**
		 * （2） 设置调用方法的参数值，如果没有参数，可以省略。 要注意的是，参数必须和服务声明的@WebParam里面的变量名对应
		 */
		soapObj.addProperty("name", name);
		// （3） 生成调用Webservice方法的SOAP请求信息。该信息由SoapSerializationEnvelope对象描述
		SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(
				SoapEnvelope.VER11);
		// envelope.bodyOut = rpc;
		envelope.dotNet = false;
		envelope.setOutputSoapObject(soapObj);
		// （4）创建HttpTransportsSE对象。通过AndroidHttpTransport类的构造方法可以指定WebService的WSDL文档的URL
		HttpTransportSE ht = new HttpTransportSE(URL);
		try {
			// (5)使用call方法调用WebService方法
			ht.call(null, envelope);
			// （6）使用getResponse方法获得WebService方法的返回结果
			if (envelope.getResponse() != null) {
				System.out.println(envelope.getResponse());
				result = String.valueOf(envelope.getResponse());
//				Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT)
//						.show();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return result;
	}
 
}

原文链接：https://blog.csdn.net/zxnlmj/article/details/25887447

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