Question

我知道有很多与此主题相关的SO帖子，但没有一个在这里工作。

我正在从班级 UserEntry.java进行sendBroadcast调用： ---

final Intent intent = new Intent(DeviceScanActivity.ACTION_DISCONNECTED);
intent.putExtra(DeviceScanActivity.EXTRAS_DEVICE_NAME, bdDevice.getName());
intent.putExtra(DeviceScanActivity.EXTRAS_DEVICE_ADDRESS,  bdDevice.getAddress());
getActivity().sendBroadcast(intent);

我在班级 DeviceScanActivity.java中定义了我的广播接收器：为---

private final BroadcastReceiver mUpdateReceiver = 
new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();
            device_name = intent.getExtras().getString(DeviceScanActivity.
            EXTRAS_DEVICE_NAME);
            device_address = intent.getExtras().getString(DeviceScanActivity.
            EXTRAS_DEVICE_ADDRESS);
            if (ACTION_CONNECTED.equals(action)) {
                mConnected = "Connected";
                invalidateOptionsMenu();
            } else if (ACTION_DISCONNECTED.equals(action)) {
                mConnected = "Disconnected";
                invalidateOptionsMenu();
            } else if (ACTION_CONNECTING.equals(action)) {
                mConnected = "Connecting";
                invalidateOptionsMenu();
            }
            else
            {
                mConnected = "";
                invalidateOptionsMenu();
            }
        }
    };

@Override
    protected void onResume() {
        super.onResume();

        registerReceiver(mUpdateReceiver, makeUpdateIntentFilter());
}

 @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(mUpdateReceiver);
}

因此，用户点击“连接”按钮，系统sendBroadcast就会调用UserEntry，然后用户切换到课程DeviceScanActivity，永远不会调用onReceive。

Answer 1

您正在DeviceScanActivity.java中注册BroadcastReceiver，这意味着在DeviceScanActivity处于活动状态之前，它不会被注册。

换句话说，由于没有可用于接收广播的接收器，广播将会丢失。

没有调用BroadcastReceiver的onReceive方法

1 个答案: