Android 判断当前网络状态从而改变某些控件的状态

   我们做Android 应用时，会遇到这样一种情况，例如：当前界面或控件当有网时展示数据,无网时提示网络出现问题（吐司），或是在控件之上覆盖一个控件，根据网络的状态让显示隐藏，当然这是我粗浅的一种想法，我在这写的是咋样判断网络状态（有网 没网），判断网络我这有两种想法，一种是在你组件使用之前利用下面一的方法的得到网络状态true或false,从而进行相对应操作；二是写一个服务service让他监听当前网络状态然后通过广播将网络状态记录到sharedPreferences·，控件通过·当前的sharePreferences得到网络状态，从而进行相应的操作。（我现在知识有限，也许大家有更好的方法请指教，提点）

一

/**

* 判断网络链接

*

* @param context

* @return

*/

public static boolean isNetWorkAvailable(Context context) {

ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

if (connectivity == null) {

return false;

} else {

NetworkInfo[] info = connectivity.getAllNetworkInfo();

if (info != null) {

for (int i = 0; i < info.length; i++) {

if (info[i].getState() == NetworkInfo.State.CONNECTED) {

return true;

}

}

}

}

return false;

}



二

package com.example.networkstatusdemo;

import android.support.v7.app.ActionBarActivity;

import org.w3c.dom.Text;

import android.app.Activity;

import android.app.Service;

import android.content.Intent;

import android.content.SharedPreferences;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.TextView;

public class MainActivity extends Activity {
MyService myservice;
SharedPreferences sharedpreferences;
TextView text;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text=(TextView)findViewById(R.id.textview_main);
myservice=new MyService();
Intent intent=new Intent(MainActivity.this,myservice.getClass());
MainActivity.this.startService(intent);
if(write()!=4){
text.setText("网络出现错误！");
}
}
public int write(){
SharedPreferences preferences=getSharedPreferences("wangluo",MODE_PRIVATE);
int num=preferences.getInt("code",-1);
return num;
}

}

package com.example.networkstatusdemo;

import android.app.Service;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.content.SharedPreferences;

import android.content.SharedPreferences.Editor;

import android.graphics.AvoidXfermode.Mode;

import android.net.ConnectivityManager;

import android.net.NetworkInfo;

import android.os.IBinder;

import android.preference.Preference;

import android.widget.Toast;

public class MyService extends Service{
private ConnectivityManager connectivitymanager;
private NetworkInfo networkinfo;

SharedPreferences sharedPreferences=null;

private BroadcastReceiver mRecevicer=new BroadcastReceiver(){

@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String action=intent.getAction();
if(action.equals(ConnectivityManager.CONNECTIVITY_ACTION)){
Toast.makeText(getApplicationContext(),"网络状态改变",Toast.LENGTH_LONG).show();
}
connectivitymanager=(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
networkinfo=connectivitymanager.getActiveNetworkInfo();
if(networkinfo!=null&&networkinfo.isAvailable()){
String name=networkinfo.getTypeName();
new Thread(new Runnable() {

@Override
public void run() {
// TODO Auto-generated method stub
read();
}
}).start();
}else{
Toast.makeText(getApplicationContext(),"没有可用网路",Toast.LENGTH_SHORT).show();
delete();
}
}

};

@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
@Override
public void onCreate() {
// TODO Auto-generated method stub
super.onCreate();
sharedPreferences=getSharedPreferences("wangluo",Context.MODE_PRIVATE);
IntentFilter intent=new IntentFilter();
intent.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(mRecevicer, intent);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub

return super.onStartCommand(intent, flags, startId);
}
public void read(){
Editor editor=sharedPreferences.edit();
editor.putInt("code",4);
editor.commit();
}

public void delete(){
sharedPreferences.edit().clear().commit();
}

}

请单文件：

<?xml version="1.0" encoding="utf-8"?>

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

    package="com.example.networkstatusdemo"

    android:versionCode="1"

    android:versionName="1.0" >

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

   

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="21" />

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

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name=".MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <service android:name="com.example.networkstatusdemo.MyService">

            

        </service>

    </application>

</manifest>