动画的button（按下时缩小，松开时恢复）

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

#import "AppDelegate.h"
#import "RootViewController.h"
@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];

    self.window.rootViewController = [[RootViewController alloc] init];

    [self.window makeKeyAndVisible];
    return YES;
}

@end

#import <UIKit/UIKit.h>

@interface RootViewController : UIViewController

@end

#import "RootViewController.h"
@interface RootViewController ()
{
    CGFloat buttonScale;//比例
}
@end

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //初始化button
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    buttonScale = 1.0;
    button.frame = CGRectMake(, , , );
    [button setTitle:@"按钮" forState:];
    [button setBackgroundImage:[UIImage imageNamed:@"button"] forState:];
    [button addTarget:self action:@selector(buttonDownAction:) forControlEvents:UIControlEventTouchDown];
    [button addTarget:self action:@selector(buttonAction:) forControlEvents:UIControlEventTouchUpInside | UIControlEventTouchUpOutside];
    [self.view addSubview:button];
}
/**
 *  按钮按下时，执行的方法
 */
- (void)buttonDownAction:(UIButton*)sender{
    CGFloat scale = buttonScale < 1.0 ? 1.0 : 0.9;
    //变小
    [UIView animateWithDuration:0.25 animations:^{
        sender.transform = CGAffineTransformMakeScale(scale, scale);
    }];
    NSLog(@"变小");
}
/**
 *  松开按钮时，执行的方法
 */
- (void)buttonAction:(UIButton*)sender{
    //恢复原来的尺寸
    [UIView animateWithDuration:0.25 animations:^{
        sender.transform = CGAffineTransformMakeScale(1.0, 1.0);
    } completion:^(BOOL finished) {
        //在此执行相应操作
        NSLog(@"恢复");
    }];
}

@end