Android-活动的生命周期详解

Activity https://developer.android.google.cn/training/basics/activity-lifecycle/
管理 Activity 生命周期 https://developer.android.google.cn/training/basics/activity-lifecycle/
Activity生命周期：

本次演示的界面：

MainActivity：

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical"
    android:layout_gravity="center"
    android:gravity="center">

    <Button
        android:id="@+id/NormalActivity"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Start NormalActivity"
        android:textAllCaps="false"
        android:textSize="30sp"
        />

    <Button
        android:id="@+id/DialogActivity"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="Start DialogActivity"
        android:textAllCaps="false"
        android:textSize="30sp"
        />


</LinearLayout>

package com.zgh.leo.activitylifecycle;

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

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    private Button button1;
    private Button button2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.d(TAG, "onCreate: ");
        super.onCreate(savedInstanceState);
        if (savedInstanceState!=null){
            //获取未保存的数据
            savedInstanceState.getString("data");
        }
        setContentView(R.layout.activity_main);

        //初始化Button及设置监听
        init();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        //保存未保存的数据
        outState.putString("data","未保存的数据");
    }

    private void init() {
        button1 =findViewById(R.id.NormalActivity);
        button2 =findViewById(R.id.DialogActivity);

        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setClass(MainActivity.this,NormalActivity.class);
                startActivity(intent);
            }
        });

        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setClass(MainActivity.this,DialogActivity.class);
                startActivity(intent);
            }
        });

    }


    @Override
    protected void onRestart() {
        Log.d(TAG, "onRestart: ");
        super.onRestart();
    }

    @Override
    protected void onDestroy() {
        Log.d(TAG, "onDestroy: ");
        super.onDestroy();
    }

    @Override
    protected void onStop() {
        Log.d(TAG, "onStop: ");
        super.onStop();
    }

    @Override
    protected void onPause() {
        Log.d(TAG, "onPause: ");
        super.onPause();
    }

    @Override
    protected void onResume() {
        Log.d(TAG, "onResume: ");
        super.onResume();
    }

    @Override
    protected void onStart() {
        Log.d(TAG, "onStart: ");
        super.onStart();
    }
}

NormalActivity：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".NormalActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:text="NormalActivity"
        android:textSize="30sp"
        android:textAllCaps="false"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

package com.zgh.leo.activitylifecycle;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class NormalActivity extends AppCompatActivity {

    private static final String TAG = "NormalActivity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_normal);
    }
}

DialogActivity：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".DialogActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:text="DialogActivity"
        android:textSize="30sp"
        android:textAllCaps="false"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

package com.zgh.leo.activitylifecycle;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class DialogActivity extends AppCompatActivity {

    private static final String TAG = "DialogActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dialog);
    }
}

1.当启动Mainactivity时，会依次调用：

2019-01-18 22:24:54.676 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onCreate: 
2019-01-18 22:24:54.928 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onStart: 
2019-01-18 22:24:54.930 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onResume:

2.当点击StartNormalActivity按钮时，会依次调用：

2019-01-18 22:26:16.492 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onPause: 
2019-01-18 22:26:17.319 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onStop:

3.点击返回键，依次调用：

2019-01-18 22:27:35.260 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity:onRestart: 
2019-01-18 22:27:35.261 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onStart: 
2019-01-18 22:27:35.261 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onResume:

4.当点击StartDialogActivity按钮时，会依次调用：

2019-01-18 22:29:07.696 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onPause:

5.点击返回键，会依次调用：

2019-01-18 22:29:51.164 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onResume:

6.继续点击返回键退出应用时，会依次调用：

2019-01-18 22:30:51.865 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onPause: 
2019-01-18 22:30:52.568 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity: onStop: 
2019-01-18 22:30:52.571 23062-23062/com.zgh.leo.activitylifecycle D/MainActivity:onDestroy:

Android生命周期演示代码：https://download.csdn.net/download/qq_41113081/10926794