向下一个Activity发送数据
Intent使用Bundle对象存放待传递的数据信息。
Bundle对象操作各类型数据的读写方法

a页面发送

package com.example.chapter03;

import androidx.appcompat.app.AppCompatActivity;

import android.content.ComponentName;
import android.content.Intent;
import android.graphics.Color;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.chapter03.util.DateUtil;
import com.example.chapter03.util.Utils;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private TextView tv_send;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv_send = findViewById(R.id.tv_send);
        findViewById(R.id.tv_send).setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        Intent intent = new Intent(this, TextViewActivity.class);
        Bundle bundle = new Bundle();
        bundle.putString("request_time", DateUtil.getNowTime());
        bundle.putString("request_content", tv_send.getText().toString());
        intent.putExtras(bundle);
        startActivity(intent);
    }
}

b页面接收

package com.example.chapter03;

import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import com.example.chapter03.util.Utils;

public class TextViewActivity extends AppCompatActivity implements View.OnClickListener {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_text_view);
        TextView tv_receive = findViewById(R.id.tv_receive);
        Bundle bundle = getIntent().getExtras();
        String request_time = bundle.getString("request_time");
        String request_content = bundle.getString("request_content");
        String desc = String.format("受到请求消息：\n请求时间%s\n请求内容%s", request_time, request_content);
        tv_receive.setText(desc);
    }

    @Override
    public void onClick(View view) {
        finish();
    }
}