【转】IOS屏幕旋转与View的transform属性之间的关系，比较底层

iTouch，iPhone，iPad设置都是支持旋转的，如果我们的程序能够根据不同的方向做出不同的布局，体验会更好。

　　如何设置程序支持旋转呢，通常我们会在程序的info.plist中进行设置Supported interface orientations，添加我们程序要支持的方向，而且程序里面每个viewController也有方法

　　supportedInterfaceOrientations(6.0及以后)

　　shouldAutorotateToInterfaceOrientation(6.0之前的系统)

　　通过viewController的这些方法，我们可以做到更小粒度的旋转控制，如程序中仅仅允许个别界面旋转。

 

一、屏幕旋转背后到底做了什么呢？

　　下面我们看个简单的例子，用xcode新建一个默认的单视图工程，然后在对应viewController的响应旋转后的函数中输出一下当前view的信息，代码如下：

SvRotateViewController

//
//  SvRotateViewController.m
//  SvRotateByTransform
//
//  Created by  maple on 4/21/13.
//  Copyright (c) 2013 maple. All rights reserved.
//

#import "SvRotateViewController.h"

@interface SvRotateViewController ()

@end

@implementation SvRotateViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    self.view.backgroundColor = [UIColor grayColor];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return YES;
}

- (BOOL)shouldAutorotate
{
    return YES;
}

- (NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationMaskAll;
}

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    NSLog(@"UIViewController will rotate to Orientation: %d", toInterfaceOrientation);
}

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
    NSLog(@"did rotated to new Orientation, view Information %@", self.view);
}

@end

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