[Android] Activity communicate information over two Intent

Now we do a test, FirstAvtivity pass information to SecondActivity, after SecondActivity be destroyed, SecondActivity return information to FirstActivity.

1. MainActivity.java (FirstActivity)

package com.example.lisiwei.twoactivitytransfer;

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

public class MainActivity extends AppCompatActivity {

    Button button = null;
    private final int REQUESTCODE = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button = findViewById(R.id.Mainbutton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, Main2Activity.class);
                // Person是一信息类，set 属性，这里做序列化通过Intent传递给secondActivity
                Person person = new Person();
                Bundle bundle = new Bundle();
                person.setAge(15);
                person.setName("lisiwei");
                // bundle序列化
                bundle.putSerializable("gaofushuai",person);
                // put 到 Intent中
                intent.putExtras(bundle);
                // 用startActivityForResult而不用startActivity, 前者在Activity销毁之后可以根据REQUESTCODE，来判断是不是我们需		   要处理的Activity返回的
                startActivityForResult(intent,REQUESTCODE);
            }
        });

    }

// 重新pnActivityResult， 第一个参数就是 REQUESTCODE,用来判断是不是FirstActivity启动的, 第二个参数就是销毁Activity传回来做判断是否调用成功，data secondActivity传回来的
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case REQUESTCODE:{
                if (RESULT_OK == resultCode){
                    String requenstStr = data.getStringExtra("return_text");
                    Toast.makeText(this, requenstStr, Toast.LENGTH_LONG).show();
                }
            }
        }
    }
}

2 Main2Activity.java (SecondActivity)

package com.example.lisiwei.twoactivitytransfer;

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

public class Main2Activity extends AppCompatActivity {

    Button button = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        // get bundle
        Bundle bundle = getIntent().getExtras();
        // 从bundle反序列化
        Person person = (Person) bundle.getSerializable("gaofushuai");
        String str = "age : " + person.getAge() + " name :" + person.getName();
        Toast.makeText(this,str,Toast.LENGTH_LONG).show();
        button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String str = "i had got it";
                Intent intent = new Intent();
                intent.putExtra("return_text",str);
                // 返回给启动它的Activity的消息
                setResult(RESULT_OK, intent);
                finish();
            }
        });
    }
}

Class 3 properties, Person.java

package com.example.lisiwei.twoactivitytransfer;

import java.io.Serializable;

public class Person implements Serializable{
    private int age;
    private String name;
    Person(){

    }

    public void setAge(int age){
        this.age = age;
    }

    public void setName(String name){
        this.name = name;
    }

    public int getAge(){
        return age;
    }

    public String getName(){
        return name;
    }

}

Complete code: https://download.csdn.net/download/lisiwei1994/10801178