Activity生命周期和Activity页面之间数据传递

1、什么是Activity？
    Android四大基本组件：
    Activity(手机屏幕)
    BroadcastReceiver（广播接受者）
    Services服务  
    ContentProvider（内容提供者）
2,、调用生命周期方法：
    <1>按home键
    <2>和打开另外一个窗口，再按返回键
    <3>横竖屏切换

    <4>Activity的状态保存和恢复

3、Activity的生命周期方法和Activity的三种生命周期

MainActivity页面跳转到ThinkActivity页面写心情，然后在跳回MainActivity页面的效果图

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.zking.administrator.myapplication8.MainActivity">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入用户名:"
        android:id="@+id/et_main_uname"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="写心情"
        android:onClick="writeThink"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/tv_main_showThink"/>
</LinearLayout>

<?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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.zking.administrator.myapplication8.ThinkActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/tv_think_showName"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:lines="5"
        android:hint="请写心情"
        android:gravity="top"
        android:id="@+id/et_think_content"/>
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="确定"
        android:onClick="ok"/>
</LinearLayout>

entity包

package com.zking.administrator.entity;

import android.os.Parcel;
import android.os.Parcelable;

/**
 * Created by Administrator on 2017/6/16.
 */

public class Person implements Parcelable{
    private int pid;
    private String pname;
    private int page;

    public Person(){

    }
    public Person(int pid,String pname,int page){
        this.pid=pid;
        this.pname=pname;
        this.page=page;
    }

    protected Person(Parcel in) {
        pid = in.readInt();
        pname = in.readString();
        page = in.readInt();
    }

    public static final Creator<Person> CREATOR = new Creator<Person>() {
        @Override
        public Person createFromParcel(Parcel in) {
            return new Person(in);
        }

        @Override
        public Person[] newArray(int size) {
            return new Person[size];
        }
    };

    public int getPid() {
        return pid;
    }

    public void setPid(int pid) {
        this.pid = pid;
    }

    public String getPname() {
        return pname;
    }

    public void setPname(String pname) {
        this.pname = pname;
    }

    public int getPage() {
        return page;
    }

    public void setPage(int page) {
        this.page = page;
    }

    @Override
    public String toString() {
        return "Person{" +
                "pid=" + pid +
                ", pname='" + pname + '\'' +
                ", page=" + page +
                '}';
    }

    @Override
    public int describeContents() {
        return 0;
    }

    //把属性写到序列化中
    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(pid);
        dest.writeString(pname);
        dest.writeInt(page);
    }
}

package com.zking.administrator.myapplication8;

import android.content.Intent;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

import com.zking.administrator.entity.Person;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    private EditText et_main_uname;
    private TextView tv_main_showThink;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_main_uname = (EditText) findViewById(R.id.et_main_uname);
        tv_main_showThink = (TextView) findViewById(R.id.tv_main_showThink);
        Log.i("test","onCreate");
//        String content=getIntent().getStringExtra("content");
//        tv_main_showThink.setText(content);
    }
    public void writeThink(View view){
        String uname=et_main_uname.getText().toString();
        Intent intent=new Intent(this,ThinkActivity.class);
        //传递基本数据类型
//        intent.putExtra("uanme",uname);
//        intent.putExtra("uage",18);
        //传递Bundle
//        Bundle bundle=new Bundle();
//        bundle.putString("uname",uname);
//        bundle.putInt("uage",19);
//        intent.putExtra("bundle",bundle);
        //传递对象
        Person person1=new Person(1,"呵呵",19);
        Person person2=new Person(2,"卡卡",18);
        Person person3=new Person(3,"试试",17);

        ArrayList<Person> persons=new ArrayList<>();
        persons.add(person1);
        persons.add(person2);
        persons.add(person3);

        //intent.putExtra("persons",persons);
        //传递对象集合
        intent.putParcelableArrayListExtra("persons",persons);
        //startActivity(intent);
        //带有目的的跳转
        startActivityForResult(intent,0x201);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        Log.i("test","onActivityResult");
        String content=data.getStringExtra("content");
        tv_main_showThink.setText(content);
    }
}

package com.zking.administrator.myapplication8;

import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

import com.zking.administrator.entity.Person;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Administrator on 2017/6/16.
 */

public class ThinkActivity extends AppCompatActivity{


    private TextView tv_think_showName;
    private EditText et_think_content;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_think);
        tv_think_showName = (TextView) findViewById(R.id.tv_think_showName);
        et_think_content = (EditText) findViewById(R.id.et_think_content);
        //获取第一个页面传递过来的数据
//        String uname=getIntent().getStringExtra("uname");
//        int uage=getIntent().getIntExtra("uage",0);
        //接受bundle
//        Bundle bundle=getIntent().getBundleExtra("bundle");
//        String uname=bundle.getString("uname");
//        int uage=bundle.getInt("uage");
        //接受对象
//        Person person= (Person) getIntent().getSerializableExtra("person");
//        Person person=getIntent().getParcelableExtra("person");

        //接受对象集合
        List<Person> persons=getIntent().getParcelableArrayListExtra("persons");
        tv_think_showName.setTextSize(30);
        for (Person person:persons) {
            tv_think_showName.setText(tv_think_showName.getText()+"\n"+person.toString());
        }
    }

    public void ok(View view){
        String content=et_think_content.getText().toString();
        Intent intent=new Intent();
        intent.putExtra("content",content);

        //设置结果
        setResult(0x100,intent);
        //自杀(干掉自己，干掉当前的Activity)
        finish();

        //startActivity(intent);
    }
}