Android EventBus使用方法

一款解决了高耦合的使用简单的在Activity,Fragment,Thread,Service之间通信的框架，堪称神器！中高阶工程师必备！

类似bean类，可以用来区别接受者

public class MessageEvent {

    private String message;

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

    public String getMessage() {
        return message;
    }

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

1.接收消息的活动

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

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

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

public class MainActivity extends AppCompatActivity {

    private Button button;

    private TextView textView;
    // 用来判断是否需要停止事件的继续分发
    private boolean stopDelivery = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = findViewById(R.id.textview);
        button = findViewById(R.id.button);
        textView.setText("你好");
        EventBus.getDefault().register(this);
        Log.d("TAG", "onCreate: ===========注册");
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, MainActivity2.class);
                startActivity(intent);
            }
        });
    }

    //三个参数1.线程选择，2.是否是粘性事件，3.优先级
    //接收通知
    @Subscribe(threadMode = ThreadMode.MAIN)
    public void setEvent(MessageEvent messageEvent) {
        Log.d("TAG", "onCreate: ===========执行");
        textView.setText(messageEvent.getMessage());
        if (stopDelivery) {
            // 终止事件的继续分发
            EventBus.getDefault().cancelEventDelivery(messageEvent);
        }
    }

    @Override
    protected void onDestroy() {
        if (EventBus.getDefault().isRegistered(this)) {
            EventBus.getDefault().unregister(this);
        }
        super.onDestroy();
    }
}

2.发起订阅的活动

import androidx.appcompat.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 MainActivity2 extends AppCompatActivity {

    private Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        button = findViewById(R.id.button1);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //发送通知
                EventBus.getDefault().post(new MessageEvent("大家好"));
                Log.d("TAG", "onCreate: ===========发送");
                finish();
            }
        });
    }
}