NetworkInfo.isConnected（）和NetworkInfo.getDetailedState（）== NetworkInfo.DetailedState.CONNECTED之間的區別。 用什么？

Question

我想知道哪種方法可以精確檢查網絡狀態是否成功連接。

Answer 1

因此，如果我們查看NetworkInfo.java類的源代碼 ，您將看到網絡詳細狀態被聲明為Enum，

public enum DetailedState {
        /** Ready to start data connection setup. */
        IDLE,
        /** Searching for an available access point. */
        SCANNING,
        /** Currently setting up data connection. */
        CONNECTING,
        /** Network link established, performing authentication. */
        AUTHENTICATING,
        /** Awaiting response from DHCP server in order to assign IP address information. */
        OBTAINING_IPADDR,
        /** IP traffic should be available. */
        CONNECTED,
        /** IP traffic is suspended */
        SUSPENDED,
        /** Currently tearing down data connection. */
        DISCONNECTING,
        /** IP traffic not available. */
        DISCONNECTED,
        /** Attempt to connect failed. */
        FAILED,
        /** Access to this network is blocked. */
        BLOCKED,
        /** Link has poor connectivity. */
        VERIFYING_POOR_LINK,
        /** Checking if network is a captive portal */
        CAPTIVE_PORTAL_CHECK
    }

但是如果您閱讀這些詳細狀態的評論，請在下面說明這些

網絡連接的細粒度狀態。 很少有應用程序可能會對此詳細程度感興趣。 大多數應該使用android.net.NetworkInfo.State狀態。

NetworkInfo.java類中的isConnected()方法僅檢查State.CONNECTED State ，

public boolean isConnected() {
        synchronized (this) {
            return mState == State.CONNECTED;
        }
    }

基本上如果你使用

NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
boolean isConnected = activeNetwork != null &&
                      activeNetwork.isConnectedOrConnecting();

這應該足夠，因為上面的代碼將查詢活動網絡並確定它是否具有Internet連接。 一旦你知道它，你就可以繼續訪問互聯網資源。

Answer 2

Java的：

 ConnectivityManager manager =
               (ConnectivityManager)getApplication.getSystemService(Context.CONNECTIVITY_SERVICE);

NetworkInfo info=manager.getActiveNetworkInfo()

if(info!=null && info.isConnected()){
// you are online for sure.
}

科特林：

val manager = application.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager

        val info = manager.getActiveNetworkInfo()

        if (info != null && info.isConnected()) {
            // you are online for sure.
        }

我在開發中使用Above代碼來確保我的設備已連接到Internet。

閱讀此主題以了解其中的差異以及如何更改狀態

Answer 3

源代碼

public boolean isConnected() {
    synchronized (this) {
        return mState == State.CONNECTED;
    }
}

所以它是一樣的

從這里https://developer.android.com/training/monitoring-device-state/connectivity-monitoring#java

ConnectivityManager cm =
        (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);

NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
boolean isConnected = activeNetwork != null &&
                      activeNetwork.isConnected();

您需要將此添加到清單中

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