/** * 作者： 葉應是葉 * 時間： 2017/8/22 18:25 * 描述： */public class WifiStateView extends AppCompatImageView {  private WifiManager wifiManager;  private WifiHandler wifiHandler;  //沒有開啟Wifi或開啟了Wifi但沒有連接  private static final int LEVEL_NONE = 0;  //Wifi信號等級（最弱）  private static final int LEVEL_1 = 1;  //Wifi信號等級  private static final int LEVEL_2 = 2;  //Wifi信號等級  private static final int LEVEL_3 = 3;  //Wifi信號等級（最強）  private static final int LEVEL_4 = 4;  private final String TAG = "WifiStateView";  private static class WifiHandler extends Handler {    //虛引用    private WeakReference<WifiStateView> stateViewWeakReference;    WifiHandler(WifiStateView wifiStateView) {      stateViewWeakReference = new WeakReference<>(wifiStateView);    }    @Override    public void handleMessage(Message msg) {      WifiStateView wifiStateView = stateViewWeakReference.get();      if (wifiStateView == null) {        return;      }      switch (msg.what) {        case LEVEL_1:          wifiStateView.setImageResource(R.drawable.wifi_1);          break;        case LEVEL_2:          wifiStateView.setImageResource(R.drawable.wifi_2);          break;        case LEVEL_3:          wifiStateView.setImageResource(R.drawable.wifi_3);          break;        case LEVEL_4:          wifiStateView.setImageResource(R.drawable.wifi_4);          break;        case LEVEL_NONE:        default:          wifiStateView.setImageResource(R.drawable.wifi_none);          break;      }    }  }  private BroadcastReceiver wifiStateReceiver = new BroadcastReceiver() {    @Override    public void onReceive(Context context, Intent intent) {      Log.e(TAG, "action " + intent.getAction());      switch (intent.getAction()) {        case WifiManager.WIFI_STATE_CHANGED_ACTION:          if (wifiManager.getWifiState() == WifiManager.WIFI_STATE_DISABLING) {            wifiHandler.sendEmptyMessage(LEVEL_NONE);          }          break;        case WifiManager.RSSI_CHANGED_ACTION:          if (wifiManager.getWifiState() == WifiManager.WIFI_STATE_DISABLED) {            wifiHandler.sendEmptyMessage(LEVEL_NONE);            return;          }          WifiInfo wifiInfo = wifiManager.getConnectionInfo();          int level = WifiManager.calculateSignalLevel(wifiInfo.getRssi(), 5);          Log.e(TAG, "level:" + level);          wifiHandler.sendEmptyMessage(level);          break;      }    }  };  public WifiStateView(Context context) {    this(context, null);  }  public WifiStateView(Context context, @Nullable AttributeSet attrs) {    this(context, attrs, 0);  }  public WifiStateView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);    wifiManager = (WifiManager) context.getApplicationContext().getSystemService(Context.WIFI_SERVICE);    wifiHandler = new WifiHandler(this);  }  @Override  protected void onAttachedToWindow() {    super.onAttachedToWindow();    IntentFilter intentFilter = new IntentFilter();    //Wifi連接狀態變化    intentFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);    //Wifi信號強度變化    intentFilter.addAction(WifiManager.RSSI_CHANGED_ACTION);    getContext().registerReceiver(wifiStateReceiver, intentFilter);  }  @Override  protected void onDetachedFromWindow() {    super.onDetachedFromWindow();    wifiHandler.removeCallbacksAndMessages(null);    getContext().unregisterReceiver(wifiStateReceiver);  }}