Android Data Analyse(4)--NetworkCapabilities

NetworkCapabilities

NetworkCapabilities 可以理解为网络能力的标识，类似于Call的Capability. 更加类似于一个工具类。

标志该网络有哪些能力，可以干些什么事，这也就决定了该类有些特定的方法。

    /**
     * Adds the given capability to this {@code NetworkCapability} instance.
     * Multiple capabilities may be applied sequentially.  Note that when searching
     * for a network to satisfy a request, all capabilities requested must be satisfied.
     *
     * @param capability the {@code NetworkCapabilities.NET_CAPABILITY_*} to be added.
     * @return This NetworkCapabilities instance, to facilitate chaining.
     * 给该network添加特定的capability
     */
    public NetworkCapabilities addCapability(int capability) {
        if (capability < MIN_NET_CAPABILITY || capability > MAX_NET_CAPABILITY) {
            throw new IllegalArgumentException("NetworkCapability out of range");
        }
        mNetworkCapabilities |= 1 << capability;
        return this;
    }

    /**
     * Tests for the presence of a capabilitity on this instance.
     *
     * @param capability the {@code NetworkCapabilities.NET_CAPABILITY_*} to be tested for.
     * @return {@code true} if set on this instance.
     * 判断该网络是否拥有某种特定的网络。
     */
    public boolean hasCapability(int capability) {
        if (capability < MIN_NET_CAPABILITY || capability > MAX_NET_CAPABILITY) {
            return false;
        }
        return ((mNetworkCapabilities & (1 << capability)) != 0);
    }

常见的capabilities 有 NET_CAPABILITY_MMS , NET_CAPABILITY_SUPL ,NET_CAPABILITY_DUN 等

标志网络传输类型，说明是通过哪种方式传递的。

    /**
     * Gets all the transports set on this {@code NetworkCapability} instance.
     *
     * @return an array of {@code NetworkCapabilities.TRANSPORT_*} values
     *         for this instance.
     * 获得传输的类型
     */
    public int[] getTransportTypes() {
        return enumerateBits(mTransportTypes);
    }

传输的类型有：

    /**
     * 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;

NetworkCapabilities 本身没有太多功能，主要是对网络进行标识。从而供其他模块调用时判断或构建Networkrequest.

    private String getImsIface() {
        final NetworkState[] states;
        try {
            states = mConnManager.getAllNetworkState();
        } catch (RemoteException e) {
            Log.e(this, "getVoiceCallIfaces RemoteException" + e);
            return null;
        }

        if (states != null) {
            for (NetworkState state : states) {
            //判断链接的network是否有reach 运营商ims的能力
                if (state.networkInfo.isConnected() && state.networkCapabilities.hasCapability(
                        NetworkCapabilities.NET_CAPABILITY_IMS)) {
                    final boolean isMobile = ConnectivityManager.isNetworkTypeMobile(
                            state.networkInfo.getType());
                    final String baseIface = state.linkProperties.getInterfaceName();
                    if (isMobile)
                        return baseIface;
                }
            }
        }
        return null;
    }

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