package com.example.android_activity;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.widget.Toast;

public class MainActivity extends Activity {

    //创建Activity时调用，一个生命周期只有一次执行

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        //绑定当前窗体的布局文件

        setContentView(R.layout.activity_main);

        Toast.makeText(this,"Activity创建时调用onCreate()方法",Toast.LENGTH_LONG).show();

    }

    //去到注册窗体

    public void toRegister(View view){

        Intent intent=new Intent(this,RegisterActivity.class);

        startActivity(intent);

    }

    //Activity启动时调用

    @Override

    protected void onStart() {

        super.onStart();

        Toast.makeText(this,"Activity被启动时调用onStart()方法",Toast.LENGTH_LONG).show();

    }

    //Activity进入运行状态时调用[进入激活必经之路]

    @Override

    protected void onResume() {

        super.onResume();

        Toast.makeText(this,"Activity进入运行状态时调用onResume方法",Toast.LENGTH_LONG).show();

    }

    //Activity从Stop状态重启时调用

    @Override

    protected void onRestart() {

        super.onRestart();

        Toast.makeText(this,"Activity从停止状态重启时调用onRestart()方法",Toast.LENGTH_LONG).show();

    }

    //Activity进入暂停状态[退出激活必经之路]

    @Override

    protected void onPause() {

        super.onPause();

        Toast.makeText(this,"Activity进入暂停状态时调用onPause()方法",Toast.LENGTH_LONG).show();

    }

    //进入停止状态时调用

    @Override

    protected void onStop() {

        super.onStop();

        Toast.makeText(this,"Activity进入停止状态时调用onStop()方法",Toast.LENGTH_LONG).show();

    }

    //销毁Activity实例,一个生命周期只有一次执行

    @Override

    protected void onDestroy() {

        super.onDestroy();

        Toast.makeText(this,"Activity被销毁时调用onDestroy()方法",Toast.LENGTH_LONG).show();

    }

}

package com.example.android_activity;

import android.app.Activity;

import android.os.Bundle;

public class RegisterActivity extends Activity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_register);

    }

}

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/activity_main"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    >

    <Button

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:textSize="30sp"

        android:onClick="toRegister"

        android:text="用户注册"

        />

</LinearLayout>