屏幕自动旋转和调节大小

1.新建工程名为RotateDemo ， File->New->Project ->single View Application -> next

2.在view视图上添加两个Label，

//  RotateViewController.h
#import <UIKit/UIKit.h>

@interface RotateViewController : UIViewController
{
    UILabel *upLabel;
    UILabel *downLabel;
    CGRect upFrame;
    CGRect dowmFrame;
}
@end

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    upFrame = CGRectMake(10, 10, 300, 100);
    dowmFrame = CGRectMake(10, 350, 300, 100);
//    初始化Label
    upLabel = [[UILabel alloc] initWithFrame:upFrame];
    downLabel = [[UILabel alloc] initWithFrame:dowmFrame];
//    设置标题
    [upLabel setText:@"在上面"];
    [downLabel setText:@"在下面"];
//    设置字体大小
    upLabel.font = [UIFont systemFontOfSize:48.0];
    downLabel.font = [UIFont systemFontOfSize:48.0];
//    字体加粗
    upLabel.font = [UIFont boldSystemFontOfSize:48];
    downLabel.font = [UIFont boldSystemFontOfSize:48];

//    如果label标题很长，可以使用此方法让标题大小自动适合label宽度
    /*
    upLabel.adjustsFontSizeToFitWidth =YES;
    downLabel.adjustsFontSizeToFitWidth = YES;
    */

//    设置Label标题居中对其
    upLabel.textAlignment=UITextAlignmentCenter;
    downLabel.textAlignment = UITextAlignmentCenter;
//    设置label标题颜色
    [upLabel setTextColor:[UIColor blackColor]];
    [downLabel setTextColor:[UIColor blueColor]];

//    设置Label透明度0是完全透明，1是不透明
    upLabel.alpha = 0.9;
    downLabel.alpha = 0.4;
//    把label添加到视图上
    [self.view addSubview:upLabel];
    [self.view addSubview:downLabel];
}

⌘「Command 键」+ ->  可以切换视图旋转方向，或者菜单栏点击硬件，在下拉菜单里有旋转方向控制选项，运行结果截图
 

        出现这情况是iphone根据重力感应所产生的，view视图发生改变，但是两个label坐标并未改变，所以在下面那个label并未显示出来，还有个 就是当Home方向向上的时候，和第二中情况一样了，label坐标发生变化了，这是针对iphone的特殊情况，当有电话呼入的时候，如果Home键在 上，那么我们的话筒和听筒就反了，主要调用的是这个实例方法

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

他的意思就是不支持Home键在上方，如果是ipad我们只需return YES；意思支持屏幕任何方向的旋转，

ios设置了四个方向变量

UIInterfaceOrientationPortrait//正常情况下的竖屏
UIInterfaceOrientationPortraitUpsideDown//Home键在上
UIInterfaceOrientationLandscapeLeft//Home键在左
UIInterfaceOrientationLandscapeRight//Home键在右

3.重写willAnimateRotationToInterfaceOrientation方法，重新设置控件的大小与位置

- (void) willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    if (UIInterfaceOrientationIsPortrait(toInterfaceOrientation)) {
        upLabel.frame = upFrame;
        downLabel.frame = dowmFrame;
    }
    else {
        upLabel.frame = CGRectMake(90, 10, 300, 100);
        downLabel.frame = CGRectMake(90, 190, 300, 100);
    }
}

       当屏幕出现旋转开始并在动画发生之前自动调用此方法，首先if判断屏幕方向是竖着(UIInterfaceOrientationIsPortrait)的还是横着(UIInterfaceOrientationIsLandscape)，toInterfaceOrientation是传入参数，从变量命名意思我们就可以看出是界面方向，此方法是对label进行屏幕不同方向的重新布局，

处理屏幕旋转问题的函数还有几个,他们之间有的放在一起会相互制约，而且在模拟器下只有

willAnimateRotationToInterfaceOrientation    <span style="color: rgb(51, 51, 51); font-family: Arial; line-height: 26px; text-align: left; text-indent: 28px;font-size:16px; ">willRotateToInterfaceOrientation     <span style="color: rgb(51, 51, 51); font-family: Arial; line-height: 26px; text-align: left; text-indent: 28px;font-size:16px; ">didRotateFromInterfaceOrientation</span></span>

三个方法可以使用，其他的只能在真机上使用：此处参考的是http://blog.csdn.net/sjzsp/article/details/6364585

//在视图旋转动画前一半发生之前自动调用
-(void)willAnimateFirstHalfOfRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration 

{

}

//在视图旋转动画后一半发生之前自动调用
-(void)willAnimateSecondHalfOfRotationFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation duration:(NSTimeInterval)duration

{

}

//该方法将在视图旋转之前自动调用

-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration 

{

}

//该方法在试图旋转完成之后调用
-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation

{

}

//在试图旋转动画前一半发生之前自动调用
-(void)didAnimateFirstHalfOfRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation

{

}

4.若在在视图中添加一张背景图片，图片会不会自动旋转调节大小呢，拖动一张background.png图片到工程中，在ViewDidLoad上添加一下代码，并运行下结果：

UIImage *image = [UIImage imageNamed:@"background.png"];
    //用图片初始化一张视图
    UIImageView *backgroundView = [[UIImageView alloc] initWithImage:image];
    //更改视图视图属性，设置为YES
    backgroundView.userInteractionEnabled=YES;

    //添加至主视图,两个方法实现功能一样
   [self setView:backgroundView];
//   [self.view addSubview:backgroundView];

从中我们可以看出，图片是可以根据视图自动调节大小的，但是我想提的一点[self.view addSubview:backgroundView];测试用的是[self setView:backgroundView];他们功能是一样的，不要放在两个[self.View addSubView:upLabel];h和[self.view addSubView:downLabel]后面，否则就会把两个Label给覆盖了，两个label是在backgroundView上没的；

5.对于比较复杂的界面上一种方法就不是那么好控制，如何去实现视图的横向和纵向视图的分离呢，分别设计视图横向模式和纵向模式，然后在实现他们之间的切换操作，代码如下

//  RotateViewController.h
#import <UIKit/UIKit.h>

//宏定义，把度数转化成弧度
#define degreesToRadians(x) (M_PI * (x) / 180.0)

@interface RotateViewController : UIViewController
{
    UILabel *upLabel;
    UILabel *downLabel;
    CGRect upFrame;
    CGRect dowmFrame;

    UIImageView *backgroundView;

    UIView *landscape;
    UIView *portrait;

}


@end

viewDidLoad方法

- (void)viewDidLoad
{
    [super viewDidLoad];


    portrait = [[UIView alloc] initWithFrame:self.view.frame];

    landscape = [[UIView alloc]initWithFrame:CGRectMake(0, 0,480, 30)];




    UIImage *image = [UIImage imageNamed:@"background.png"];
    //用图片初始化一张视图
   backgroundView = [[UIImageView alloc] initWithImage:image];
    //更改视图视图属性，设置为YES
    backgroundView.userInteractionEnabled=YES;



    upFrame = CGRectMake(10, 10, 300, 100);
    dowmFrame = CGRectMake(10, 350, 300, 100);
    //    初始化Label
    upLabel = [[UILabel alloc] initWithFrame:upFrame];
    downLabel = [[UILabel alloc] initWithFrame:dowmFrame];
    //    设置标题
    [upLabel setText:@"在上面"];
    [downLabel setText:@"在下面"];
    //    设置字体大小
    upLabel.font = [UIFont systemFontOfSize:48.0];
    downLabel.font = [UIFont systemFontOfSize:48.0];
    //    字体加粗
    upLabel.font = [UIFont boldSystemFontOfSize:48];
    downLabel.font = [UIFont boldSystemFontOfSize:48];

    //    如果label标题很长，可以使用此方法让标题大小自动适合label宽度

    //    upLabel.adjustsFontSizeToFitWidth =YES;
    //    downLabel.adjustsFontSizeToFitWidth = YES;


    //    设置Label标题居中对其
    upLabel.textAlignment=UITextAlignmentCenter;
    downLabel.textAlignment = UITextAlignmentCenter;
    //    设置label标题颜色
    [upLabel setTextColor:[UIColor blackColor]];
    [downLabel setTextColor:[UIColor blueColor]];

    //    设置Label透明度0是完全透明，1是不透明
    upLabel.alpha = 0.9;
    downLabel.alpha = 0.4;



    //    把label添加到视图上
    [self.view addSubview:backgroundView];
    [self.view addSubview:upLabel];
    [self.view addSubview:downLabel];


}

为了支持任何方向的旋转，shouldAutorotateToInterfaceOrientation，方法的返回值设置成return YES; 然后继续重写willAnimateRotationToInterfaceOrientation方法

- (void) willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    /*****************************************
    if (UIInterfaceOrientationIsPortrait(toInterfaceOrientation)) {
        upLabel.frame = upFrame;
        downLabel.frame = dowmFrame;
    }
    else {
        upLabel.frame = CGRectMake(90, 10, 300, 100);
        downLabel.frame = CGRectMake(90, 190, 300, 100);
    }
     *****************************************/
    if (toInterfaceOrientation == UIInterfaceOrientationPortrait) {


        self.view = portrait;

        upLabel.frame = upFrame;
        downLabel.frame = dowmFrame;
        [self setView:backgroundView];
        [self.view addSubview:upLabel];
        [self.view addSubview:downLabel];
        self.view.transform = CGAffineTransformIdentity;
        self.view.transform = CGAffineTransformMakeRotation(degreesToRadians(0));
        self.view.bounds = CGRectMake(0, 0, 320, 460);
        NSLog(@"----------->down");
    }
    else if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft) {

        self.view = landscape;

        upLabel.frame = CGRectMake(90, 10, 300, 100);
        downLabel.frame = CGRectMake(90, 190, 300, 100);

        [self setView:backgroundView];
        [self.view addSubview:upLabel];
        [self.view addSubview:downLabel];

//        需要修改transfom属性，此处是回复默认状态，每次变换前都要置位，不然你变换用的坐标系统不是屏幕坐标系统（即绝对坐标系统），而是上一次变换后的坐标系统
        self.view.transform = CGAffineTransformIdentity;
//        获取旋转弧度数
        self.view.transform = CGAffineTransformMakeRotation(degreesToRadians(-90));
        self.view.bounds = CGRectMake(0, 0, 480, 300);
        NSLog(@"----------->Left");
    }
    else if (toInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown) {
                self.view = portrait;


        upLabel.frame = upFrame;
        downLabel.frame = dowmFrame;
        [self setView:backgroundView];
        [self.view addSubview:upLabel];
        [self.view addSubview:downLabel];

        self.view.transform = CGAffineTransformIdentity;
        self.view.transform = CGAffineTransformMakeRotation(degreesToRadians(180));
        self.view.bounds = CGRectMake(0, 0,320 , 460);
        NSLog(@"----------->up");
    }
    else if (toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {

        self.view = landscape;

        upLabel.frame = CGRectMake(90, 10, 300, 100);
        downLabel.frame = CGRectMake(90, 190, 300, 100);
        [self setView:backgroundView];
        [self.view addSubview:upLabel];
        [self.view addSubview:downLabel];

        self.view.transform = CGAffineTransformIdentity;
        self.view.transform  = CGAffineTransformMakeRotation(degreesToRadians(90));
        self.view.bounds = CGRectMake(0, 0, 480, 300);


        NSLog(@"----------->right");
    }
}

self.view.transform = CGAffineTransformIdentity;

self.view.transform = CGAffineTransformMakeRotation(degreesToRadians(-90));

两次修改transform，原因是第一次需要修改transfom属性此处是回复默认状态，每次变换前都要置位，不然你变换用的坐标系统不是屏幕坐标系统（即绝对坐标系统），而是上一次变换后的坐标系统  ，第二次是设置旋转的弧度数，本人再次犯了一个很大低级错误，纠结了两个多小时，和书上一样的代码为什么在Home在上方和Home在下方是屏幕旋转方向不对，这两个方向上视图总是斜着的，郁闷死了，最后才发现是因为CGAffineTransformMakeRotation传参的时候，直接把角度数180和90传进去了，未作弧度装换，你可不要还这样低级错误哦；

最后再把运行截图贴上

  

6.还可以使用IB工具，使用Size Inpector实现自动旋转 也可以实现屏幕旋转和大小调节，需要使用控件，在此就不做测试， 附上源代码：http://download.csdn.net/detail/duxinfeng2010/4404812