EventBus使用详解

基本使用

（1）自定义一个类，可以是空类，比如：

public class FirstEvent {
    private String mMsg;
    public FirstEvent(String msg) {
        mMsg = msg;
    }
    public String getMsg(){
        return mMsg;
    }
}

（2）在要接收消息的页面注册：

eventBus.register(this);

（3）发送消息

eventBus.post(new FirstEvent  event);

（4）接受消息的页面实现(共有四个函数，各功能不同，这是其中之一，可以选择性的实现，这里先实现一个)：

public void onEventMainThread(FirstEvent  event) {}

（5）解除注册

eventBus.unregister(this);

实战

public class MainActivity extends AppCompatActivity {

    Button btn;
    TextView tv;

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

        EventBus.getDefault().register(this);

        btn = (Button) findViewById(R.id.btn_try);
        tv = (TextView)findViewById(R.id.tv);

        btn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent intent = new Intent(getApplicationContext(),SecondActivity.class);
                startActivity(intent);
            }
        });
    }

    @Subscribe
    public void onEventMainThread(FirstEvent event) {
        String msg = "onEventMainThread收到了消息：" + event.getMsg();
        tv.setText(msg);
        Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
    }
    @Override
    public void onDestroy(){
        super.onDestroy();
        EventBus.getDefault().unregister(this);
    }
}

public class SecondActivity extends AppCompatActivity {

    private Button btn_FirstEvent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        btn_FirstEvent = (Button) findViewById(R.id.btn_first_event);

        btn_FirstEvent.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                EventBus.getDefault().post(new FirstEvent("FirstEvent btn clicked"));
                finish();
            }
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical">

    <Button
        android:id="@+id/btn_try"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="btn_bty"/>
    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"/>
    <TextView
        android:id="@+id/tv1"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"/>

</LinearLayout>

activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical" >

    <Button
        android:id="@+id/btn_first_event"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="First Event"/>

</LinearLayout>