如果有一个意图过滤器,为什么要检查Intent在BroadcastReceiver中的操作

Question

我正在查看Android蓝牙开发人员文档并查看此处的代码片段,并想知道如果您已经过滤了特定的意图操作类型,为什么需要检查该意图的操作.

// Create a BroadcastReceiver for ACTION_FOUND
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        // When discovery finds a device
        if (BluetoothDevice.ACTION_FOUND.equals(action)) {
            // Get the BluetoothDevice object from the Intent
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            // Add the name and address to an array adapter to show in a ListView
            mArrayAdapter.add(device.getName() + "\n" + device.getAddress());
        }
    }
};
// Register the BroadcastReceiver
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter); // Don't forget to unregister during onDestroy

Answer 1

该文件对BroadcastReceiver.onReceive()包含该注意:

registerReceiver(BroadcastReceiver, IntentFilter)应用程序清单中和应用程序清单中使用的Intent过滤器不保证是独占的.它们提示操作系统如何找到合适的收件人.发件人可以强制传递给特定收件人,绕过过滤器解析.因此,onReceive()实现应仅响应已知操作,忽略它们可能收到的任何意外Intent.