目录结构：
contents structure [+]
获取网络信息需要在AndroidManifest.xml文件中加入相应的权限。
1.判断网络
1.1 判断是否有网络连接
public boolean isNetworkConnected(Context context) {if (context != null) {ConnectivityManager mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();if (mNetworkInfo != null) {return mNetworkInfo.isAvailable();}}return false;} 1.2判断WIFI网络是否可用
public boolean isWifiConnected(Context context) {if (context != null) {ConnectivityManager mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo mWiFiNetworkInfo = mConnectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);if (mWiFiNetworkInfo != null) {return mWiFiNetworkInfo.isAvailable();}}return false;} 这里需要注意，该方法只是判断当前环境下是否有可用的WIFI，并不是判断是否已经连接上WIFI。
1.3 判断MOBILE网络是否可用
public boolean isMobileConnected(Context context) {if (context != null) {ConnectivityManager mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo mMobileNetworkInfo = mConnectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);if (mMobileNetworkInfo != null) {return mMobileNetworkInfo.isAvailable();}}return false;} 1.4 获取当前网络连接的类型信息
public static int getConnectedType(Context context) {if (context != null) {ConnectivityManager mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();if (mNetworkInfo != null && mNetworkInfo.isAvailable()) {return mNetworkInfo.getType();}}return -1;} getType()的返回值可以是ConnectivityManager中的TYPE_MOBILE、TYPE_WIFI、TYPE_WIMAX、TYPE_ETHERNET、TYPE_BLUETOOTH、其他类型。
1.5 准确判断网络是否可用
有时候我们连接上一个没有外网连接的WiFi或者有线就会出现这种极端的情况，目前Android SDK还不能识别这种情况，一般的解决办法就是ping一个外网。
在使用下面这个方法之前应该加上如下的权限：
/* @author suncat * @category 判断是否有外网连接（普通方法不能判断外网的网络是否连接，比如连接上局域网） * @return */public static final boolean ping() {String result = null;try { String ip = "www.baidu.com";// ping 的地址，可以换成任何一种可靠的外网 Process p = Runtime.getRuntime().exec("ping -c 3 -w 100 " + ip);// ping网址3次 // 读取ping的内容，可以不加 InputStream input = p.getInputStream(); BufferedReader in = new BufferedReader(new InputStreamReader(input)); StringBuffer stringBuffer = new StringBuffer(); String content = ""; while ((content = in.readLine()) != null) { stringBuffer.append(content); } Log.d("------ping-----", "result content : " + stringBuffer.toString()); // ping的状态 int status = p.waitFor(); if (status == 0) { result = "success"; return true; } else { result = "failed"; } } catch (IOException e) { result = "IOException"; } catch (InterruptedException e) { result = "InterruptedException"; } finally { Log.d("----result---", "result = " + result); } return false;} 2.监听网络
定义广播接受者：
BroadcastReceiver connectionReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { ConnectivityManager mConnectivityManager = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo mNetworkInfo = mConnectivityManager .getActiveNetworkInfo(); int type = -1; if (mNetworkInfo != null && mNetworkInfo.isAvailable()) { type = mNetworkInfo.getType(); } if (type == ConnectivityManager.TYPE_WIFI) { Toast.makeText(MainActivity.this, "wifi", Toast.LENGTH_SHORT) .show(); } else if (type == ConnectivityManager.TYPE_MOBILE) { Toast.makeText(MainActivity.this, "网络可用", Toast.LENGTH_SHORT) .show(); }else if(type==-1){ Toast.makeText(MainActivity.this, "网络不可用", Toast.LENGTH_SHORT) .show(); }else{ Toast.makeText(MainActivity.this, "未知网络", Toast.LENGTH_SHORT) .show(); } } }; 在合适的位置注册：
IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION); registerReceiver(connectionReceiver, intentFilter);
在合适的位置取消注册：
unregisterReceiver(connectionReceiver);