Android中的eventBus傳值

第一步：在build.gradle中添加依賴
dependencies {
    
 compile 'org.greenrobot:eventbus:3.0.0'
}

第二步：創建一個 Event類： 注意：enum 不是class

public enum  Event {
    //消息名，可以根據這個名字判斷是哪個消息
 IMAGE_LOADER_SUCCESS;
}

//------------主布局文件------------------------

<TextView
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/tv_text" />
<Button
 android:layout_width="match_parent"
 android:layout_height="40dp"
 android:text="點擊跳轉到TwoActivity"
 android:id="@+id/bt_button"/>

//-----------TwoActivity布局-----------------------

<Button
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/bt_button2"
 android:text="發送消息"/>

//---------創建一個消息了---MessageEvent ------------------------

public class MessageEvent {
    private String message;

 public String getMessage() {
 return message;
 }

 public void setMessage(String message) {
 this.message = message;
 }

 public MessageEvent(String message) {
 this.message = message;
 }

 public MessageEvent() {
 }
}

//--------------MainActivity -中我們注冊事件，用於接收消息，退出時需要注銷-----------------

package eventbusdemo.wode.com.eventbusdemo;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import org.greenrobot.eventbus.EventBus;
import org.greenrobot.eventbus.Subscribe;
import org.greenrobot.eventbus.ThreadMode;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

 private Button bt_button;
 private TextView tv_text;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 //找到控件
 bt_button = (Button) findViewById(R.id.bt_button);
 tv_text = (TextView) findViewById(R.id.tv_text);
 //在需要訂閱事件的地方注冊事件
 EventBus.getDefault().register(this);
 //設置監聽
 bt_button.setOnClickListener(this);

 }
 //用於接收傳MessageEvent這個類的消息
 @Subscribe(threadMode = ThreadMode.MAIN)
 public void onShowMessageEvent(MessageEvent messageEvent) {
 tv_text.setText("MainActivity:" + messageEvent.getMessage());
 }

 //用於接收沒有傳值的消息
 /* @Subscribe
 public void onEventMainThread(Event event){
 switch (event){
 case IMAGE_LOADER_SUCCESS:
 Log.i("MainActivity--","IMAGE_LOADER_SUCCESS");
 tv_text.setText("IMAGE_LOADER_SUCCESS");
 break;
 }
 }*/

 @Override
 public void onClick(View v) {
 switch (v.getId()){
 case R.id.bt_button:
 Intent intent=new Intent(MainActivity.this,TwoActivity.class);
 startActivity(intent);
 break;
 }
 }

 //(5)取消消息訂閱
 @Override
 protected void onDestroy() {
 super.onDestroy();
 EventBus.getDefault().unregister(this);
 }
}

//--------------TwoActivity 中，用於發送消息------------------------

package eventbusdemo.wode.com.eventbusdemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import org.greenrobot.eventbus.EventBus;

public class TwoActivity extends AppCompatActivity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_two);
 Button bt_button2= (Button) findViewById(R.id.bt_button2);
 bt_button2.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 //(3)產生事件，即發送消息
 // EventBus.getDefault().post(Event.IMAGE_LOADER_SUCCESS);
 //傳值
 EventBus.getDefault().post(new MessageEvent("哈哈哈哈哈"));
 }
 });

 }
}