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Sticky Events 粘性事件可以理解为Message做了持久化,直到Message被消费为止。无需注册即可发送Message。
下面的例子:在MainActivity发送事件,在StickyActivity里注册并且接收事件
A. MainActivity 发送事件:
EventBus.getDefault().postSticky(new MessageEvent("http://www.netkiller.cn"));
B. StickyActivity 接收事件
1. 注册
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. 取消注册
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;
}
}