一. 前言

1. NetworkInfo的过时

Android 编译sdk版本为29时，NetworkInfo 过时了。

我们以前都是通过NetworkInfo的isConnected来判断网络是否连接，NetworkInfo的getType来判断网络连接类型。

2. NetworkCapabilities的使用

我们将使用NetworkCapabilities来代替NetworkInfo判断网络是否连接，以及网络的连接类型。

3. 记住在清单文件中添加网络状态查询权限

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<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="swu.xl.networkstate">

    <!--查看网络状态权限-->
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

二. 判断当前网络是否连接

1. 是否联网的判断方法

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/**
 * 判断是否联网
 */
private boolean isOnline(@NonNull Context context){
    //获取 ConnectivityManager
    ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    assert connectivityManager != null;

    //如果版本大于 Build.VERSION_CODES.M （23）
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

        //获取 NetWork
        Network network = connectivityManager.getActiveNetwork();

        if(network != null) {
            //获取 NetworkCapabilities
            NetworkCapabilities networkCapabilities = connectivityManager.getNetworkCapabilities(network);

            return (networkCapabilities != null && networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET));
        }

    }else {

        //获取NetworkInfo
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();

        return (networkInfo != null && networkInfo.isConnected());
    }

    return false;
}

2. hasCapability

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/**
 * Tests for the presence of a capability on this instance.
 *
 * @param capability the capabilities to be tested for.
 * @return {@code true} if set on this instance.
 */
public boolean hasCapability(@NetCapability int capability)

capability 可以是 NetworkCapabilities.NET_CAPABILITY_INTERNET ，更多的参数可以查看系统源码。

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/**
 * Indicates that this network should be able to reach the internet.
 * 意思就是可以联网
 */
public static final int NET_CAPABILITY_INTERNET = 12;

3. 为什么使用 Build.VERSION_CODES.M 区分版本

getActiveNetwork 这个方法最低使用 API 是 Build.VERSION_CODES.M（23）。

三. 判断当前网络的状态

1. 网络状态的判断方法

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/**
 * 判断当前网络状态
 * @param context
 * @return
 */
private boolean testNetWorkState(@NonNull Context context){
    //获取 ConnectivityManager
    ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    assert connectivityManager != null;

    //如果版本大于23
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

        //获取 NetWork
        Network network = connectivityManager.getActiveNetwork();

        if(network!=null){
            //获取 NetworkCapabilities
            NetworkCapabilities networkCapabilities = connectivityManager.getNetworkCapabilities(network);

            if(networkCapabilities != null){
                if(networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)){
                    //WIFI
                    Toast.makeText(context, "WIFI", Toast.LENGTH_SHORT).show();
                    return true;
                }else if(networkCapabilities.hasTransport(TRANSPORT_CELLULAR)){
                    //移动数据
                    Toast.makeText(context, "mobile", Toast.LENGTH_SHORT).show();
                    return true;
                }
            }
        }

    }else {
        //获取NetworkInfo
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();

        if (networkInfo != null) {
            if (networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
                //WIFI
                Toast.makeText(context, "WIFI", Toast.LENGTH_SHORT).show();
                return true;
            } else if (networkInfo.getType() == ConnectivityManager.TYPE_MOBILE) {
                //移动数据
                Toast.makeText(context, "mobile", Toast.LENGTH_SHORT).show();
                return true;
            }
        }
    }

    return false;
}

2. hasTransport

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/**
 * Tests for the presence of a transport on this instance.
 *
 * @param transportType the transport type to be tested for.
 * @return {@code true} if set on this instance.
 */
public boolean hasTransport(@Transport int transportType) {
    return isValidTransport(transportType) && ((mTransportTypes & (1 << transportType)) != 0);
}

transportType 参数的类型如下：

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/**
 * 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;

/**
 * Indicates this network uses a Bluetooth transport.
 */
public static final int TRANSPORT_BLUETOOTH = 2;

/**
 * Indicates this network uses an Ethernet transport.
 */
public static final int TRANSPORT_ETHERNET = 3;

/**
 * Indicates this network uses a VPN transport.
 */
public static final int TRANSPORT_VPN = 4;

/**
 * Indicates this network uses a Wi-Fi Aware transport.
 */
public static final int TRANSPORT_WIFI_AWARE = 5;

/**
 * Indicates this network uses a LoWPAN transport.
 */
public static final int TRANSPORT_LOWPAN = 6;

/**
 * Indicates this network uses a Test-only virtual interface as a transport.
 *
 * @hide
 */
@TestApi
public static final int TRANSPORT_TEST = 7;

四. 监听网络状态的变化

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public class MainActivity extends AppCompatActivity {

    //回调
    ConnectivityManager.NetworkCallback callback = new ConnectivityManager.NetworkCallback(){

        //可用网络接入
        //当我们的网络的某个能力发生了变化回调，会回调多次
        @Override
        public void onCapabilitiesChanged(@NonNull Network network, @NonNull NetworkCapabilities networkCapabilities) {
            //一般在此处获取网络类型然后判断网络类型

            //Toast.makeText(MainActivity.this, "网络接入", Toast.LENGTH_SHORT).show();
        }

        //网络可用的回调
        @Override
        public void onAvailable(@NonNull Network network) {
            //和 onLost 成对出现

            Toast.makeText(MainActivity.this, "网络可用", Toast.LENGTH_SHORT).show();
        }

        //网络断开
        @Override
        public void onLost(@NonNull Network network) {
            //如果通过ConnectivityManager#getActiveNetwork()返回null，表示当前已经没有其他可用网络了。

            Toast.makeText(MainActivity.this, "网络断开", Toast.LENGTH_SHORT).show();
        }
    };

    //注册回调
    private void registerNetworkCallback(Context context) {
        //获取 ConnectivityManager
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        assert connectivityManager != null;

        //获取 NetworkRequest 的 Builder
        NetworkRequest.Builder builder = new NetworkRequest.Builder();
        //强制使用蜂窝数据网络-移动数据
        //builder.addTransportType(TRANSPORT_CELLULAR);
        //强制使用wifi网络
        //builder.addTransportType(NetworkCapabilities.TRANSPORT_WIFI);

        //注册
        NetworkRequest networkRequest = builder.build();
        connectivityManager.registerNetworkCallback(networkRequest,callback);
    }

    //注销回调
    private void unregisterNetworkCallback(Context context) {
        //获取 ConnectivityManager
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        assert connectivityManager != null;

        //注销
        connectivityManager.unregisterNetworkCallback(callback);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    protected void onStart() {
        super.onStart();

        registerNetworkCallback(this);
    }

    @Override
    protected void onStop() {
        super.onStop();

        unregisterNetworkCallback(this);
    }
}

五. 源码参考

NetworkState

参考文章

Android多网络环境（wifi,mobile）下强制在某个网络(mobile)访问服务端以及适配

android权限（permission）大全

Android网络状态获取类 在api 29中 NetworkInfo Deprecated

android10解决NetworkInfo废弃替代NetworkInfo isConnected()问题

android 5.0 以上监听网络变化