截至2020年3月，此答案已有更新，支持API.15至API.29，您可以在原始答案之后找到它
回答2019年2月
要检查您是否在线：
boolean isOnline() {
// Checking internet connectivity
ConnectivityManager connectivityMgr = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = null;
if (connectivityMgr != null) {
activeNetwork = connectivityMgr.getActiveNetworkInfo();
}
return activeNetwork != null;
}
在android M之前/之后获取Internet连接的类型
void internetType() {
// Checking internet connectivity
ConnectivityManager connectivityMgr = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = null;
if (connectivityMgr != null) {
activeNetwork = connectivityMgr.getActiveNetworkInfo();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
NetworkCapabilities nc = connectivityMgr.getNetworkCapabilities(connectivityMgr.getActiveNetwork());
if (nc.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
// connected to mobile data
} else if (nc.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
// connected to wifi
}
} else {
if (activeNetwork.getType() == ConnectivityManager.TYPE_WIFI) {
// connected to wifi
} else if (activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE) {
// connected to mobile data
}
}
}
}
所有情况都需要访问网络状态的权限
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
2020年3月更新
从NetworkInfo过时开始，从API 29开始，我们必须使用ConnectivityManager.NetworkCallback其网络状态更改onAvailable()和onLost()回调。
用法：
- 您可以使用此库，也可以直接使用下面的实用程序类，它是该库的一部分。
特征
- 通过
LifecycleObserver对onDestroy()方法进行一些清理来实现避免内存泄漏的方式来实现生命周期意识。
- 它支持从API 15（冰淇淋三明治）到API 29（Android Q）
- 对于API 21之前的API，它使用基于上下文的
BoradcastReceiver和NetworkInfo，并ConnectivityManager.NetworkCallback用于API 21及更高版本。
- 当WiFi和蜂窝网络都打开时，当在过渡到蜂窝网络时WiFi断开连接时，连接侦听器不会中断。
- 当蜂窝网络打开时，连接WiFi并成为活动网络（因为这是首选网络）时，连接侦听器不会中断。
- 如果您要使用该库，则无需包含此权限
android.permission.ACCESS_NETWORK_STATE；但是如果要使用实用程序类，则必须包括它。
能力
- 获取当前的连接状态（在线/离线）。
- 持续检查/收听Internet连接，并在设备离线或在线时触发回叫。
- 获取活动的互联网连接的类型（WiFi或蜂窝）。
- 获取所有可用网络的类型（WiFi或蜂窝网络）。>>仅在API 21+上受支持
- 获取所有可用网络的数量>>仅API 21+支持
@RequiresApi(api = Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)
public class ConnectionUtil implements LifecycleObserver {
private static final String TAG = "LOG_TAG";
private ConnectivityManager mConnectivityMgr;
private Context mContext;
private NetworkStateReceiver mNetworkStateReceiver;
/*
* boolean indicates if my device is connected to the internet or not
* */
private boolean mIsConnected = false;
private ConnectionMonitor mConnectionMonitor;
/**
* Indicates there is no available network.
*/
private static final int NO_NETWORK_AVAILABLE = -1;
/**
* Indicates this network uses a Cellular transport.
*/
public static final int TRANSPORT_CELLULAR = 0;
/**
* Indicates this network uses a Wi-Fi transport.
*/
public static final int TRANSPORT_WIFI = 1;
public interface ConnectionStateListener {
void onAvailable(boolean isAvailable);
}
public ConnectionUtil(Context context) {
mContext = context;
mConnectivityMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
((AppCompatActivity) mContext).getLifecycle().addObserver(this);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
mConnectionMonitor = new ConnectionMonitor();
NetworkRequest networkRequest = new NetworkRequest.Builder()
.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
.addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
.build();
mConnectivityMgr.registerNetworkCallback(networkRequest, mConnectionMonitor);
}
}
/**
* Returns true if connected to the internet, and false otherwise
*
* <p>
* NetworkInfo is deprecated in API 29
* https://developer.android.com/reference/android/net/NetworkInfo
* <p>
* getActiveNetworkInfo() is deprecated in API 29
* https://developer.android.com/reference/android/net/ConnectivityManager#getActiveNetworkInfo()
* <p>
* getNetworkInfo(int) is deprecated as of API 23
* https://developer.android.com/reference/android/net/ConnectivityManager#getNetworkInfo(int)
*/
public boolean isOnline() {
mIsConnected = false;
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.P) {
// Checking internet connectivity
NetworkInfo activeNetwork = null;
if (mConnectivityMgr != null) {
activeNetwork = mConnectivityMgr.getActiveNetworkInfo(); // Deprecated in API 29
}
mIsConnected = activeNetwork != null;
} else {
Network[] allNetworks = mConnectivityMgr.getAllNetworks(); // added in API 21 (Lollipop)
for (Network network : allNetworks) {
NetworkCapabilities networkCapabilities = mConnectivityMgr.getNetworkCapabilities(network);
if (networkCapabilities != null) {
if (networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)
|| networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)
|| networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET))
mIsConnected = true;
}
}
}
return mIsConnected;
}
/**
* Returns
* <p> <p>
* <p><p> NO_NETWORK_AVAILABLE >>> when you're offline
* <p><p> TRANSPORT_CELLULAR >> When Cellular is the active network
* <p><p> TRANSPORT_WIFI >> When Wi-Fi is the Active network
* <p>
*/
public int getActiveNetwork() {
NetworkInfo activeNetwork = mConnectivityMgr.getActiveNetworkInfo(); // Deprecated in API 29
if (activeNetwork != null)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
NetworkCapabilities capabilities = mConnectivityMgr.getNetworkCapabilities(mConnectivityMgr.getActiveNetwork());
if (capabilities != null)
if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
// connected to mobile data
return TRANSPORT_CELLULAR;
} else if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
// connected to wifi
return TRANSPORT_WIFI;
}
} else {
if (activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE) { // Deprecated in API 28
// connected to mobile data
return TRANSPORT_CELLULAR;
} else if (activeNetwork.getType() == ConnectivityManager.TYPE_WIFI) { // Deprecated in API 28
// connected to wifi
return TRANSPORT_WIFI;
}
}
return NO_NETWORK_AVAILABLE;
}
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public int getAvailableNetworksCount() {
int count = 0;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
Network[] allNetworks = mConnectivityMgr.getAllNetworks(); // added in API 21 (Lollipop)
for (Network network : allNetworks) {
NetworkCapabilities networkCapabilities = mConnectivityMgr.getNetworkCapabilities(network);
if (networkCapabilities != null)
if (networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)
|| networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR))
count++;
}
}
return count;
}
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public List<Integer> getAvailableNetworks() {
List<Integer> activeNetworks = new ArrayList<>();
Network[] allNetworks; // added in API 21 (Lollipop)
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
allNetworks = mConnectivityMgr.getAllNetworks();
for (Network network : allNetworks) {
NetworkCapabilities networkCapabilities = mConnectivityMgr.getNetworkCapabilities(network);
if (networkCapabilities != null) {
if (networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI))
activeNetworks.add(TRANSPORT_WIFI);
if (networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR))
activeNetworks.add(TRANSPORT_CELLULAR);
}
}
}
return activeNetworks;
}
public void onInternetStateListener(ConnectionStateListener listener) {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
mNetworkStateReceiver = new NetworkStateReceiver(listener);
IntentFilter intentFilter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
mContext.registerReceiver(mNetworkStateReceiver, intentFilter);
} else {
mConnectionMonitor.setOnConnectionStateListener(listener);
}
}
@OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
public void onDestroy() {
Log.d(TAG, "onDestroy");
((AppCompatActivity) mContext).getLifecycle().removeObserver(this);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
if (mConnectionMonitor != null)
mConnectivityMgr.unregisterNetworkCallback(mConnectionMonitor);
} else {
if (mNetworkStateReceiver != null)
mContext.unregisterReceiver(mNetworkStateReceiver);
}
}
public class NetworkStateReceiver extends BroadcastReceiver {
ConnectionStateListener mListener;
public NetworkStateReceiver(ConnectionStateListener listener) {
mListener = listener;
}
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getExtras() != null) {
NetworkInfo activeNetworkInfo = mConnectivityMgr.getActiveNetworkInfo(); // deprecated in API 29
/*
* activeNetworkInfo.getState() deprecated in API 28
* NetworkInfo.State.CONNECTED deprecated in API 29
* */
if (!mIsConnected && activeNetworkInfo != null && activeNetworkInfo.getState() == NetworkInfo.State.CONNECTED) {
Log.d(TAG, "onReceive: " + "Connected To: " + activeNetworkInfo.getTypeName());
mIsConnected = true;
mListener.onAvailable(true);
} else if (intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, Boolean.FALSE)) {
if (!isOnline()) {
mListener.onAvailable(false);
mIsConnected = false;
}
}
}
}
}
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public class ConnectionMonitor extends ConnectivityManager.NetworkCallback {
private ConnectionStateListener mConnectionStateListener;
void setOnConnectionStateListener(ConnectionStateListener connectionStateListener) {
mConnectionStateListener = connectionStateListener;
}
@Override
public void onAvailable(@NonNull Network network) {
if (mIsConnected)
return;
Log.d(TAG, "onAvailable: ");
if (mConnectionStateListener != null) {
mConnectionStateListener.onAvailable(true);
mIsConnected = true;
}
}
@Override
public void onLost(@NonNull Network network) {
if (getAvailableNetworksCount() == 0) {
mConnectionStateListener.onAvailable(false);
mIsConnected = false;
}
}
}
}