Sticky Events 粘性事件可以理解為Message做了持久化,直到Message被消費為止。無需註冊即可發送Message。
下面的例子:在MainActivity發送事件,在StickyActivity裡註冊並且接收事件
A. MainActivity 發送事件: EventBus.getDefault().postSticky(new MessageEvent("http://www.netkiller.cn")); B. StickyActivity 接收事件 1. 註冊 EventBus.getDefault().register( this ); 2. 事件接收 @Subscribe(threadMode = ThreadMode.MAIN, sticky = true) public void onMessageEvent(MessageEvent event) { Toast.makeText(this, event.message, Toast.LENGTH_SHORT).show(); } 3. 取消註冊 EventBus.getDefault().unregister( this ) ;
Layout
<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <TextView android:id="@+id/textView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Hello World!" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" /> <Button android:id="@+id/button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:text="Button" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toBottomOf="@+id/textView" /> </android.support.constraint.ConstraintLayout>
MainActivity
package cn.netkiller.eventbus; import android.content.Intent; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Toast; import org.greenrobot.eventbus.EventBus; import org.greenrobot.eventbus.Subscribe; import org.greenrobot.eventbus.ThreadMode; import cn.netkiller.eventbus.pojo.MessageEvent; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); findViewById(R.id.button).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { EventBus.getDefault().postSticky(new MessageEvent("Hello everyone!")); startActivity(new Intent(MainActivity.this, StickyActivity.class)); } }); } }
<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".StickyActivity"> </android.support.constraint.ConstraintLayout>
StickyActivity
package cn.netkiller.eventbus; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.widget.Toast; import org.greenrobot.eventbus.EventBus; import org.greenrobot.eventbus.Subscribe; import org.greenrobot.eventbus.ThreadMode; import cn.netkiller.eventbus.pojo.MessageEvent; public class StickyActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_sticky); EventBus.getDefault().register(this); } @Override protected void onDestroy() { super.onDestroy(); EventBus.getDefault().unregister(this); } @Subscribe(threadMode = ThreadMode.MAIN, sticky = true) public void onMessageEvent(MessageEvent event) { Toast.makeText(this, event.message, Toast.LENGTH_SHORT).show(); } }
package cn.netkiller.eventbus.pojo; public class MessageEvent { public final String message; public MessageEvent(String message) { this.message = message; } }