UIVIew之霓虹灯实现

//
//  AppDelegate.m
//  NiHongPractice
//

#import "AppDelegate.h"
#define kColorValue arc4random_uniform(256) / 255.0
#define kScreenWidth [UIScreen mainScreen].bounds.size.width
#define kScreenHeight [UIScreen mainScreen].bounds.size.height

@interface AppDelegate ()

@end

@implementation AppDelegate

- (void)dealloc
{
self.window = nil;

[super dealloc];

}

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

for (int i  = 0; i < 11; i++) {

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(15*i, 15*i, kScreenWidth - 30 * i, kScreenHeight - 30 * i)];

// 色值的范围(0~255)
view.backgroundColor = [UIColor colorWithRed:kColorValue green:kColorValue blue:kColorValue alpha:1];

view.tag = 200 + i;

[self.window addSubview:view];

[view release];

}

[NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(changeColor) userInfo:nil repeats:YES]; // 每过一秒去调用changeColor方法,进行一次颜色转换

//[self changeColor];

return YES;
}

- (void)changeColor {

UIColor *color = [self.window viewWithTag:200 + 10].backgroundColor;

for (int i = 10; i >= 0; i--) {

[self.window viewWithTag:200 + i].backgroundColor = [self.window viewWithTag:200 + i - 1].backgroundColor; // 先创建的tag值小,结果显示为由外向里转换颜色

}

[self.window viewWithTag:200].backgroundColor = color;

}