Activity生命周期

 activity_act_jump.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="10dp" >

    <Button
        android:id="@+id/btn_act_next"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="跳到下个页面"
        android:textColor="#000000"
        android:textSize="17sp" />
    
    <TextView
        android:id="@+id/tv_life"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:gravity="left"
        android:textColor="#000000"
        android:textSize="17sp" />

</LinearLayout>

 DateUtil.java

package com.example.third;

import android.annotation.SuppressLint;

import java.text.SimpleDateFormat;
import java.util.Date;

public class DateUtil {
    public static String getNowDateTime() {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
        return sdf.format(new Date());
    }

    public static String getNowTime() {
        SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
        return sdf.format(new Date());
    }

    public static String getNowTimeDetail() {
        SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.SSS");
        return sdf.format(new Date());
    }

}

 MainActivity.java

package com.example.third;

import android.content.Intent;
import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;

import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.Switch;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private final static String TAG = "ActJumpActivity";
    private TextView tv_life; // 声明一个文本视图对象
    private String mStr = "";

    private void refreshLife(String desc) { // 刷新生命周期的日志信息
        Log.d(TAG, desc);
        mStr = String.format("%s%s %s %s\n", mStr, DateUtil.getNowTimeDetail(), TAG, desc);
        tv_life.setText(mStr);
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_act_jump);
        findViewById(R.id.btn_act_next).setOnClickListener(this);
        // 从布局文件中获取名叫tv_life的文本视图
        tv_life = findViewById(R.id.tv_life);
        refreshLife("onCreate");

    }

    @Override
    protected void onStart() {
        refreshLife("onStart");
        super.onStart();
    }

    @Override
    protected void onStop() {
        refreshLife("onStop");
        super.onStop();
    }

    @Override
    protected void onDestroy() {
        refreshLife("onDestroy");
        super.onDestroy();
    }


    @Override
    protected void onRestart() {
        refreshLife("onRestart");
        super.onRestart();
    }


    @Override
    protected void onPause() {
        refreshLife("onPause");
        super.onPause();
    }

    @Override
    protected void onResume() {
        refreshLife("onResume");
        super.onResume();
    }



    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.btn_act_next) {
            // 准备跳到下个活动页面ActNextActivity
            Intent intent = new Intent(this, ActNextActivity.class);
            // 期望接收下个页面的返回数据
            startActivityForResult(intent, 0);

        }
    }
}

 activity_act_next.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="10dp" >

    <Button
        android:id="@+id/btn_act_pre"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="返回上个页面"
        android:textColor="#000000"
        android:textSize="17sp" />
    
    <TextView
        android:id="@+id/tv_life"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:gravity="left"
        android:textColor="#000000"
        android:textSize="17sp" />

</LinearLayout>

ActNextActivity.java 

package com.example.third;

import android.app.Activity;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;


public class ActNextActivity extends AppCompatActivity implements OnClickListener {
    private final static String TAG = "ActNextActivity";
    private TextView tv_life; // 声明一个文本视图对象
    private String mStr = "";

    private void refreshLife(String desc) { // 刷新生命周期的日志信息
        Log.d(TAG, desc);
        mStr = String.format("%s    %s %s %s\n", mStr, DateUtil.getNowTimeDetail(), TAG, desc);
        tv_life.setText(mStr);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) { // 创建活动页面
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_act_next);
        findViewById(R.id.btn_act_pre).setOnClickListener(this);
        // 从布局文件中获取名叫tv_life的文本视图
        tv_life = findViewById(R.id.tv_life);
        refreshLife("onCreate");
    }

    @Override
    protected void onStart() { // 开始活动页面
        refreshLife("onStart");
        super.onStart();
    }

    @Override
    protected void onStop() { // 停止活动页面
        refreshLife("onStop");
        super.onStop();
    }

    @Override
    protected void onResume() { // 恢复活动页面
        refreshLife("onResume");
        super.onResume();
    }

    @Override
    protected void onPause() { // 暂停活动页面
        refreshLife("onPause");
        super.onPause();
    }

    @Override
    protected void onRestart() { // 重启活动页面
        refreshLife("onRestart");
        super.onRestart();
    }

    @Override
    protected void onDestroy() { // 销毁活动页面
        refreshLife("onDestroy");
        super.onDestroy();
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.btn_act_pre) {
            Intent intent = new Intent(); // 创建一个新意图
            intent.putExtra("life", mStr); // 把字符串参数塞给意图
            setResult(Activity.RESULT_OK, intent); // 携带意图返回前一个页面
            finish(); // 关闭当前页面

        }
    }

}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.third">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".ActNextActivity" />
    </application>

</manifest>