BroadcastReceiver相关面试题

// 广播接收器1（高优先级）
public class HighPriorityReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        String message = intent.getStringExtra("message");
        Log.d("HighPriorityReceiver", "Received: " + message);
        
        // 修改广播内容
        Bundle bundle = new Bundle();
        bundle.putString("message", message + " [Modified by High]");
        setResultExtras(bundle);
    }
}
 
// 广播接收器2（低优先级）
public class LowPriorityReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Bundle bundle = getResultExtras(true);
        String message = bundle.getString("message");
        Log.d("LowPriorityReceiver", "Received: " + message);
    }
}
 
// 在Activity中使用
public class MainActivity extends AppCompatActivity {
    private HighPriorityReceiver highPriorityReceiver;
    private LowPriorityReceiver lowPriorityReceiver;
    private static final String ACTION_CUSTOM = "com.example.CUSTOM_ACTION";
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        // 注册高优先级接收器
        highPriorityReceiver = new HighPriorityReceiver();
        IntentFilter highFilter = new IntentFilter(ACTION_CUSTOM);
        highFilter.setPriority(100);
        registerReceiver(highPriorityReceiver, highFilter);
 
        // 注册低优先级接收器
        lowPriorityReceiver = new LowPriorityReceiver();
        IntentFilter lowFilter = new IntentFilter(ACTION_CUSTOM);
        lowFilter.setPriority(50);
        registerReceiver(lowPriorityReceiver, lowFilter);
 
        // 发送有序广播
        findViewById(R.id.btnSend).setOnClickListener(v -> {
            Intent intent = new Intent(ACTION_CUSTOM);
            intent.putExtra("message", "Hello, Ordered Broadcast!");
            sendOrderedBroadcast(intent, null);
        });
    }
 
    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(highPriorityReceiver);
        unregisterReceiver(lowPriorityReceiver);
    }
}