Blog-05-《一周快速上手Kotlin For Android》-之Broadcast用法

—《一周快速上手Kotlin For Android》简介

目前Kotlin已正式成为Android的官方语言，作为Android开发者来说，学习和了解Kotlin也是属于理所当然的事情，兴许你觉得Java对于你来说才是真正的开发”利器”，使用Java你能发挥更高的效率，当然，如果如此你还是可以继续使用Java来开发Android。但对于Kotlin来说，开发Android会变得更简单一些，因为Kotlin其实就是Android开发中的语法糖，采用更简短的代码，描述更多的逻辑而已。开发语言本身就没有对错和最优，每个开发语言被开发出来的时代背景不同，需要解决的主要问题也不同。选择适合你自己的就可以。

BroadcastReceiver工作过程

Java 发送广播：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn_send = findViewById(R.id.btn_send);
        btn_send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setAction("ACTION_TEST");
                intent.putExtra("VALUE", 123);
                sendBroadcast(intent);
            }
        });
    }

}

Kotlin 发送广播：

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val btn_send = findViewById<Button>(R.id.btn_send)
        btn_send.setOnClickListener {
            val intent = Intent()
            intent.action = "ACTION_TEST"
            intent.putExtra("VALUE", 123)
            sendBroadcast(intent)
        }
    }

}

Java接收广播：

public class Main2Activity extends AppCompatActivity {

    private static final String TAG = "Main2Activity";

    private MyReceiver myReceiver;
    private IntentFilter intentFilter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        Log.d(TAG, "onCreate");
        myReceiver = new MyReceiver();
        intentFilter = new IntentFilter();
        intentFilter.addAction("ACTION_TEST");

        Intent intent = new Intent(this, MainActivity.class);
        startActivity(intent);
    }


    @Override
    protected void onResume() {
        super.onResume();
        registerReceiver(myReceiver, intentFilter);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(myReceiver);
    }

    private class MyReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            if(intent.getAction().equals("ACTION_TEST")){
                int value = intent.getIntExtra("VALUE", 0);
                Log.i(TAG, "onReceive value: " + value);
            }
        }

    }


}

Kotlin接收广播：

class Main2Activity : AppCompatActivity() {

    private var myReceiver: MyReceiver? = null
    private var intentFilter: IntentFilter? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main2)

        Log.d(TAG, "onCreate")
        myReceiver = MyReceiver()
        intentFilter = IntentFilter()
        intentFilter!!.addAction("ACTION_TEST”)

        val intent = Intent(this, MainActivity::class.java)
        startActivity(intent)
    }


    override fun onResume() {
        super.onResume()
        registerReceiver(myReceiver, intentFilter)
    }

    override fun onDestroy() {
        super.onDestroy()
        unregisterReceiver(myReceiver)
    }

    private inner class MyReceiver : BroadcastReceiver() {

        override fun onReceive(context: Context, intent: Intent) {
            if (intent.action == "ACTION_TEST") {
                val value = intent.getIntExtra("VALUE", 0)
                Log.i(TAG, "onReceive value: " + value)
            }
        }

    }

    companion object {

        private val TAG = "Main2Activity"
    }


}

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