Android中判断网络连接是否可用

摘自：http://zhxhinfu.blog.163.com/blog/static/187571188201261893241183/

一、判断网络连接是否可用
public static boolean isNetworkAvailable(Context context) { 
ConnectivityManager cm = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE);
if (cm == null) { } else {　　　　　　　
//如果仅仅是用来判断网络连接　　　　　　 
//则可以使用 cm.getActiveNetworkInfo().isAvailable(); 
NetworkInfo[] info = cm.getAllNetworkInfo(); 
if (info != null) { 
for (int i = 0; i < info.length; i++) {
     if (info[i].getState() == NetworkInfo.State.CONNECTED)
 { 
return true;
 } 
}
 } 
} 
return false;
 }

下面的不仅可以判断，如果没有开启网络的话，就进入到网络开启那个界面，具体代码如下：
protected boolean CheckNetwork() {
 // TODO Auto-generated method stub 
boolean flag=false; 
ConnectivityManager cwjManager=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
 if(cwjManager.getActiveNetworkInfo()!=null) 
flag=cwjManager.getActiveNetworkInfo().isAvailable(); 
if(!flag){ 
Builder b=new AlertDialog.Builder(this).setTitle("没有可用的网络").setMessage("请开启GPRS或WIFI网路连接"); 
b.setPositiveButton("确定",new DialogInterface.OnClickListener() { 
public void onClick(DialogInterface dialog, int which) {
 // TODO Auto-generated method stub
 Intent mIntent=new Intent("/"); 
ComponentName comp=new ComponentName("com.android.settings","com.android.settings.WirelessSettings");
 mIntent.setComponent(comp); 
mIntent.setAction("android.intent.action.VIEW");
 startActivity(mIntent); 
} 
}).setNegativeButton("取消", new DialogInterface.OnClickListener() { 
public void onClick(DialogInterface dialog, int which) { 
// TODO Auto-generated method stub dialog.cancel(); 
} 
}).create(); b.show();
 }
 return flag; 
}

用的时候可以这样用：
if(!CheckNetwork()) return;
 

 二、判断GPS是否打开
public static boolean isGpsEnabled(Context context) { 
LocationManager lm = ((LocationManager) context .getSystemService(Context.LOCATION_SERVICE));
 List<String> accessibleProviders = lm.getProviders(true); return accessibleProviders != null && accessibleProviders.size() > 0; 
}

下边这小段代码是用来判断手机的GPS服务是否为开启状态.如果是就提示用户GPS已经打开.

如果现在GPS 处于关闭状态,那么给用户一个提示, 然后打开GPS设置界面,让用户更改GPS为启动状态.
private void openGPSSettings(){
LocationManager alm =(LocationManager)this.getSystemService( Context.LOCATION_SERVICE );
if( alm.isProviderEnabled(android.location.LocationManager.GPS_PROVIDER ) ){
Toast.makeText( this, “GPS is already on”, Toast.LENGTH_SHORT ).show();
}else{
Toast.makeText( this, “Please turn on GPS”, Toast.LENGTH_SHORT ).show();
Intent myIntent = new Intent( Settings.ACTION_SECURITY_SETTINGS );startActivity(myIntent);
}
}

初始化GPS设置
private void initGPS(){
LocationManager locationManager=(LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
//判断GPS模块是否开启，如果没有则开启if(!locationManager.isProviderEnabled(android.location.LocationManager.GPS_PROVIDER)){
Toast.makeText(this, "GPS is not open,Please open it!", Toast.LENGTH_SHORT).show();
Intent intent=new Intent(Settings.ACTION_SECURITY_SETTINGS);
startActivityForResult(intent,0);
}else {
Toast.makeText(this, "GPS is ready", Toast.LENGTH_SHORT);
}
}

三、判断WIFI是否打开
public static boolean isWifiEnabled(Context context) { 
ConnectivityManager mgrConn = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); TelephonyManager mgrTel = (TelephonyManager) context .getSystemService(Context.TELEPHONY_SERVICE); 
return ((mgrConn.getActiveNetworkInfo() != null && mgrConn .getActiveNetworkInfo().getState() == NetworkInfo.State.CONNECTED) || mgrTel .getNetworkType() == TelephonyManager.NETWORK_TYPE_UMTS); 
}

四、判断是否是3G网络
public static boolean is3rd(Context context) { 
ConnectivityManager cm = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE);
 NetworkInfo networkINfo = cm.getActiveNetworkInfo(); 
if (networkINfo != null && networkINfo.getType() == ConnectivityManager.TYPE_MOBILE) { 
return true; 
}
 return false; 
}

 五、判断是wifi还是3g网络,用户的体现性在这里了，wifi就可以建议下载或者在线播放。
public static boolean isWifi(Context context) { 
ConnectivityManager cm = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkINfo = cm.getActiveNetworkInfo(); 
if (networkINfo != null && networkINfo.getType() == ConnectivityManager.TYPE_WIFI) { 
return true; 
} return false; 
}