目录结构：

contents structure [+]

1. 判断网络
1. 判断是否有网络连接
2. 判断WIFI网络是否可用
3. 判断MOBILE网络是否可用
4. 获取当前网络连接的类型信息
2. 监听网络

获取网络信息需要在AndroidManifest.xml文件中加入相应的权限。

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

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。

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);

原文地址：https://www.cnblogs.com/HDK2016/p/8978154.html