横竖屏切换时候 Activity 的生命周期

阿4is痞男

一、Activity 的 ConfigChanges 属性

官方解释： 通过设置这个属性可以使Activity捕捉设备状态变化，以下是可以被识别的内容：

CONFIG_FONT_SCALE
CONFIG_MCC
CONFIG_MNC
CONFIG_LOCALE
CONFIG_TOUCHSCREEN
CONFIG_KEYBOARD
CONFIG_NAVIGATION
CONFIG_ORIENTATION

设置方法：将下列字段用“|”符号分隔开，例如：“locale|navigation|orientation”

Value
Description

“mcc“
The IMSI mobile country code (MCC) has changed — that is, a SIM hasbeen detected and updated the MCC.移动国家号码，由三位数字组成，每个国家都有自己独立的MCC，可以识别手机用户所属国家。

“mnc“
The IMSI mobile network code (MNC) has changed — that is, a SIM hasbeen detected and updated the MNC.移动网号，在一个国家或者地区中，用于区分手机用户的服务商。

“locale“
The locale has changed — for example, the user has selected a new language that text should be displayed in.用户所在地区发生变化。

“touchscreen“
The touchscreen has changed. (This should never normally happen.)

“keyboard“
The keyboard type has changed — for example, the user has plugged in an external keyboard.键盘模式发生变化，例如：用户接入外部键盘输入。

“keyboardHidden“
The keyboard accessibility has changed — for example, the user has slid the keyboard out to expose it.用户打开手机硬件键盘

“navigation“
The navigation type has changed. (This should never normally happen.)

“orientation“
The screen orientation has changed — that is, the user has rotated the device.设备旋转，横向显示和竖向显示模式切换。

“fontScale“
The font scaling factor has changed — that is, the user has selected a new global font size.全局字体大小缩放发生改变

 

项目的AndroidManifest.xml文件配置方法:

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

02	package="com.androidres.ConfigChangedTesting"

03	android:versionCode="1"

04	android:versionName="1.0.0">

05	<application android:icon="@drawable/icon" android:label="@string/app_name">

06	<activity android:name=".ConfigChangedTesting"

07	android:label="@string/app_name"

08	android:configChanges="keyboardHidden|orientation">

09	<intent-filter>

10	<action android:name="android.intent.action.MAIN" />

11	<category android:name="android.intent.category.LAUNCHER" />

12	</intent-filter>

13	</activity>

14	</application>

15	</manifest>

 

二、横竖屏切换时候 Activity 的生命周期

测试代码：

 

01	public class AndroidLifecycle extends Activity {

02	private String TAG = "AndroidLifecycle";

03	public void onCreate(Bundle savedInstanceState) {

04	Log.i(TAG,"AndroidLifecycle =======onCreate()========");

05	super.onCreate(savedInstanceState);

06	setContentView(R.layout.main);

07

}

08

09

@Override

10	protected void onSaveInstanceState(Bundle outState) {

11	Log.i(TAG,"AndroidLifecycle =======onSaveInstanceState()========");

12	super.onSaveInstanceState(outState);

13

}

14

15

@Override

16	protected void onRestoreInstanceState(Bundle outState) {

17	Log.i(TAG,"AndroidLifecycle=======onRestoreInstanceState()========");

18	super.onRestoreInstanceState(outState);

19

}

20

21

@Override

22	public void onConfigurationChanged(Configuration newConfig) {

23	Log.i(TAG,"AndroidLifecycle =======onConfigurationChanged()========");

24	super.onConfigurationChanged(newConfig);

25

}

26

27	// Called after onCreate — or after onRestart when the activity had been

28	// stopped, but is now again being displayed to the user. It will be

29	// followed by onResume

30	protected void onStart() {

31	Log.i(TAG,"AndroidLifecycle =======onStart()========");

32	super.onStart();

33

}

34

35	// Called after onRestoreInstanceState, onRestart, or onPause, for your

36	// activity to start interacting with the user

37	protected void onResume() {

38	Log.i(TAG,"AndroidLifecycle =======onResume()========");

39	super.onResume();

40

}

41

42	// Called as part of the activity lifecycle when an activity is going into

43	// the background, but has not (yet) been killed

44	protected void onPause() {

45	Log.i(TAG,"AndroidLifecycle =======onPause()========");

46	super.onPause();

47

}

48

49	// Called when you are no longer visible to the user. You will next receive

50	// either onRestart, onDestroy, or nothing, depending on later user

51	// activity.

52	protected void onStop() {

53	Log.i(TAG,"AndroidLifecycle =======onStop()========");

54	super.onStop();

55

}

56

57	// Perform any final cleanup before an activity is destroyed

58	protected void onDestroy() {

59	Log.i(TAG,"AndroidLifecycle =======onDestroy()========");

60	super.onDestroy();

61

}

62

63	// Called after onStop when the current activity is being re-displayed to

64	// the user (the user has navigated back to it). It will be followed by

65	// onStart and then onResume

66	protected void onRestart() {

67	Log.i(TAG,"AndroidLifecycle =======onRestart()========");

68	super.onRestart();

69

}

70

}

 

Activity属性配置：

 

01	<application android:icon="@drawable/icon" android:label="@string/app_name">

02	<activity android:name=".AndroidLifecycle"

03	android:label="@string/app_name"

04	android:configChanges="orientation|keyboardHidden">

05	<intent-filter>

06	<action android:name="android.intent.action.MAIN" />

07	<category android:name="android.intent.category.LAUNCHER" />

08	</intent-filter>

09	</activity>

10

11	</application>

 

在 Android 2.2 模拟器上测试结果为：

1、不设置Activity的android:configChanges时：

Simulator_切换到横屏

 

Simulator_切换到竖屏

 

模拟器这种情况切屏会重新调用各个生命周期，切横屏时会生命周期执行一次，切竖屏时生命周期会执行两次，且横竖屏onConfigurationChanged未被调用。但是在HTC DESIRE HD(G10) 这款手机上测试结果为：生命周期都只执行一次，且横竖屏onConfigurationChanged未被调用。

 

2、设置Activity的android:configChanges="orientation"时：

Simulator_orientation_切换到横屏

 

Simulator_orientation_切换到竖屏

 

模拟器这种情况切屏还是会重新调用各个生命周期，切横屏onConfigurationChanged未执行、竖屏时onConfigurationChanged执行1次。但是在HTC DESIRE HD(G10) 这款手机上测试结果为：生命周期未发生变化，且横竖屏onConfigurationChanged都只执行一次。

 

3、设置Activity的android:configChanges="orientation|keyboardHidden"时： Simulator_orientation_keyboardHidden_切换到横屏

 

Simulator_orientation_keyboardHidden_切换到竖屏

 

模拟器这种情况切屏不会重新调用各个生命周期，切横屏时onConfigurationChanged会执行1次，切竖屏时onConfigurationChanged方法调用2次。 但是在HTC DESIRE HD(G10) 这款手机上测试结果为：横竖屏onConfigurationChanged都只执行一次。

 

结论：可以看出在G10这款真机上测试的结果比模拟器更加合理。

微软企业开发技术 | 移动开发（Google Android、Windows Mobile）技术| 嵌入式系统设计与开发 | JAVA开发