0

我对android开发很陌生，所以对于非常基本的问题提前抱歉。

在我的应用程序开始时，我想检查网络是否可用并已连接，如果是，则加载 webView 并加载 URL。这是一个简单的部分，我做到了。

现在，如果在应用程序启动时没有网络可用，我希望用户通过单击按钮（也已完成）连接到互联网，一旦连接，setContentView 到 webView 并加载 URL（大难题）。

我在这里找到了下面的代码，但我不知道如何使用它或将它放在哪里。

val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
connectivityManager?.let {
    it.registerDefaultNetworkCallback(object : ConnectivityManager.NetworkCallback() {
        override fun onAvailable(network: Network) {
            //take action when network connection is gained
        }
        override fun onLost(network: Network?) {
            //take action when network connection is lost
        }
    })
}

我的代码如下：

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    if (supportActionBar != null)
        supportActionBar?.hide()
    val myWebView = WebView(this)
    myWebView.settings.setDomStorageEnabled(true)
    myWebView.settings.setJavaScriptCanOpenWindowsAutomatically(true)
    myWebView.settings.setDatabaseEnabled(true)
    myWebView.settings.javaScriptEnabled = true
    myWebView.webViewClient = WebViewClient()
    myWebView.addJavascriptInterface(WebAppInterface(this), "Android")



    val cm = getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
    val activeNetwork: NetworkInfo? = cm.activeNetworkInfo
    val dialogBuilder = AlertDialog.Builder(this)


    if (activeNetwork!=null)
    {
        if (activeNetwork.isConnected) {
            // Toast.makeText(getApplicationContext(), "internet avialable", Toast.LENGTH_LONG).show();
            setContentView(myWebView)
            myWebView.loadUrl("https://xxxxxxx.com/xxx/xxx.html");


        }
    }else {
        setContentView(R.layout.activity_main)
        Toast.makeText(getApplicationContext(), "internet is not avialable", Toast.LENGTH_LONG).show();
        val alert = dialogBuilder.create()
        // set title for alert dialog box
        alert.setTitle("internet Not avialable")
        // show alert dialog
        alert.show()
        }
    }

    fun EnableWiFi(){

    val wifimanager=getApplicationContext().getSystemService(Context.WIFI_SERVICE) as WifiManager
    wifimanager.setWifiEnabled(true)
   }
4

2 回答 2

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你应该把下面的代码放在你的 onCreate() 方法中。通过这种方式，您将能够注册回叫以收听 Internet 连接更改

val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
connectivityManager?.let {
it.registerDefaultNetworkCallback(object : ConnectivityManager.NetworkCallback() {
    override fun onAvailable(network: Network) {
        //take action when network connection is gained
    }
    override fun onLost(network: Network?) {
        //take action when network connection is lost
    }
})

}

希望这对您有所帮助。

于 2019-12-02T13:12:20.813 回答
0

为网络更改类 NetworkChangeReceiver 添加广播接收器：BroadcastReceiver() {

    override fun onReceive(context: Context, intent: Intent) {
        //Check if connected
        context.sendBroadcast(new Intent("INTERNET_CONNECTED"));
    }
}

在清单中注册接收器如下

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<receiver
        android:name="NetworkChangeReceiver"
        android:label="NetworkChangeReceiver" >
        <intent-filter>
            <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
        </intent-filter>
</receiver>

现在在您的活动中创建一个广播接收器来接收互联网更改的结果

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    registerReceiver(broadcastReceiver, new IntentFilter("INTERNET_CONNECTED"));
}

val broadcastReceiver = object : BroadcastReceiver(){
    override fun onReceive(context: Context?, intent: Intent?) {
        //do your webview code here
    }
}

override fun onDestroy() {
    super.onDestroy()
    unregisterReceiver(broadcastReceiver);
}
于 2019-12-02T13:21:14.710 回答