Question

我是android的初学者。我只是想知道什么是广播接收器（如果可能的话有一个例子），它在onReceive（）方法上。以及我们如何使用该接收器检查互联网连接。

那么我应该使用相同的方法来检查Internet连接，还是只在Main类中创建一个静态方法并在其他类中访问它？

Answer 1

好的，所以我不是最好的程序员，但这应该有用。

这是一个片段，但您应该可以轻松地将其更改为活性。

首先制作3个变量：

Context _mContext;
BroadcastReceiver br = null;
IntentFilter filter;

你的onCreate（）中的

粘贴了这个：

BroadcastReceiver br = new MyBroadCastReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
_mContext = getActivity().getApplicationContext()
_mContext.registerReceiver(br, filter);

将此片段注册到broadcastreceiver类MyBroadCastReceiver。

现在制作一个MyBroadCastReceiver类并粘贴它：

public class MyBroadCastReceiver extends BroadcastReceiver {
            @Override
            public void onReceive(Context context, Intent intent) {
                int extraWifiState = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE,
                        WifiManager.WIFI_STATE_UNKNOWN);

    switch(extraWifiState) {
        case: WifiManager.WIFI_STATE_DISABLED:
        //do something
        break;
        case WifiManager.WIFI_STATE_ENABLED:
        //do something 
        break;
        case: WifiManager.WIFI_STATE_ENABLING:
        //do something
        break;
        case: WifiManager.WIFI_STATE_DISABLING:
        //do something
        break;
        case: WifiManager.WIFI_STATE_UNKNOWN:
        //do something with data if you desire so, I found it unreliable until now so i've done nothing with it
        }
      }
    }`

回到你的片段并将其粘贴在底部的某处：

    @Override
    public void onPause()    {
        try {
            if (br == null) {
                Log.d("Receiver", "Can't unregister a receiver which was never registered");
            } else {
                getActivity().getApplicationContext().unregisterReceiver(br);
                br = null;
            }
        } catch(Exception err)  {
            Log.e(err.getClass().getName(), err.getMessage(), err);
            Log.e("Receiver not registered", "Couldn't get context");
        }
        super.onPause();
    }

    @Override
    public void onResume()  {
        if(br != null)  {
            Log.d("Receiver", "Can't register receiver which already has been registered");
        }   else    {
            try {
                br = new MyBroadCastReceiver();
                filter = new IntentFilter();
                filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
                filter.addAction(CONNECTIVITY_SERVICE);
                _mContext = getActivity().getApplicationContext();
                _mContext.registerReceiver(br, filter);
            } catch(Exception err)   {
                Log.e(err.getClass().getName(), err.getMessage(), err);
            }
        }
        super.onResume();
    }

您应该可以在任何地方呼叫注册/取消注册广播。我希望这已经足够了

Answer 2

    <receiver
        android:name=".InternetConnectorBroadcastReceiver"
        android:enabled="true">
        <intent-filter>

            <!-- Intent filters for broadcast receiver -->
            <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
            <action android:name="android.net.wifi.STATE_CHANGE" />
        </intent-filter>
    </receiver>


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

public class InternetConnectionBroadcastReceiver extends BroadcastReceiver {
        public InternetConnectorBroadcastReceiver() {
        }

        @Override
        public void onReceive(Context context, Intent intent) {
        }

}

用于检查Internet连接的广播接收器

2 个答案: