Android(安卓)Activity生命周期举例说明（图文）

同学电话面试提及到Activity生命周期的详细说明，现整理如下：

转载请标明姓名及出处：大飞_Rflyee -http://blog.csdn.net/rflyee/article/details/9055547

必备知识背景：（详见官网：

1、Activity生命周期常见的七种方法：onCreate()、onStart()、onRestart()、onResume()、onPause()、onStop()、onDestroy()

2、调用顺序规则（官网）

下面以“Activity A转到B，再返回A”为例，说明各方法调用顺序：

情况一、B将A完全遮挡

调用顺序：

A：onCreate() - onStart() - onResume() - onPause()

B：onCreate() - onStart() - onResume()

A：onStop()

B：onPause()

A：onRestart() - onStart() - onResume()

B ：onStop() - onDestroy()

实例：

启动应用，第一个activity

logCat视图如下：

启动第二个activity，将第一个完全覆盖

logCat视图如下：

按下返回键，重现回到第一个activity之后logCat视图如下：

附源代码（仅供参考），转载请标明作者及出处：大飞_Rflyee - http://blog.csdn.net/rflyee/article/details/9055547

MainActivity.java

package com.example.myactivitylife;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.util.Log;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MainActivity extends Activity {private static final String TAG = "--activityLife--";private Button bt1 = null;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);bt1 = (Button)findViewById(R.id.button1);bt1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Intent intent = new Intent(MainActivity.this,SecindActivity.class);startActivity(intent);}});Log.i(TAG, "onCreate_first");}@Overrideprotected void onStart() {super.onStart();Log.i(TAG, "onStart_first");}@Overridepublic void onRestart(){super.onRestart();Log.i(TAG, "onRestart_first");}@Overridepublic void onResume(){super.onResume();Log.i(TAG, "onResume_first");}@Overridepublic void onPause(){super.onPause();Log.i(TAG,"onPause_first");}@Overridepublic void onStop(){super.onStop();Log.i(TAG, "onStop_first");}@Overridepublic void onDestroy(){super.onDestroy();Log.i(TAG, "onDestroy_first");}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}}

activity_main.xml

<RelativeLayout 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"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >    <TextView        android:id="@+id/textview1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="this is the first activity!" />    <Button         android:id="@+id/button1"        android:layout_below="@id/textview1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Next Activity"/></RelativeLayout>

SecondActivity.java

package com.example.myactivitylife;import android.app.Activity;import android.os.Bundle;import android.util.Log;public class SecindActivity extends Activity{private final String tag = "--dialog--";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.second);Log.i(tag, "onCreate_second");}@Overrideprotected void onDestroy() {super.onDestroy();Log.i(tag, "onDestroy_second");}@Overrideprotected void onPause() {super.onPause();Log.i(tag, "onPause_second");}@Overrideprotected void onRestart() {super.onRestart();Log.i(tag, "onRestart_second");}@Overrideprotected void onResume() {super.onResume();Log.i(tag, "onResume_second");}@Overrideprotected void onStart() {super.onStart();Log.i(tag, "onStart_second");}@Overrideprotected void onStop() {super.onStop();Log.i(tag, "onStop_second");}}

second.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >        <TextView         android:id="@+id/next_textview"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="this the second activity!"/></LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.myactivitylife"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="10"        android:targetSdkVersion="17" />    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="com.example.myactivitylife.MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <activity             android:name=".SecindActivity">                    </activity>    </application></manifest>

情况二、
B不能将A完全遮挡

调用顺序：

A：onCreate() - onStart() - onResume() - onPause()

B：onCreate() - onStart() - onResume() - onPause()

A：onResume()

B ：onStop() - onDestroy()

实例效果图：

启动A - 启动B -返回A整个过程的logCat视图：

附源代码（仅供参考），

只需将情况一中的AndroidManifest.xml稍作改动即可（将第二个activity的Theme声明为Theme.Dialog）

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.myactivitylife"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="10"        android:targetSdkVersion="17" />    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="com.example.myactivitylife.MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <activity             android:name=".SecindActivity"            android:theme="@android:style/Theme.Dialog">                    </activity>    </application></manifest>

转载请标明作者及出处：大飞_Rflyee - http://blog.csdn.net/rflyee/article/details/9055547

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