效果圖

- (void)viewDidLoad

{

[super viewDidLoad];

// Label初始化顏色

[_label setBackgroundColor:[UIColor colorWithRed:0 green:0 blue:0 alpha:100]];

// view背景顏色改變

// 1/20.0 讓1秒內執行20次可能會誤差1次

NSTimer *timer =[NSTimerscheduledTimerWithTimeInterval:1/20.0 target:self selector:@selector(testChangeViewBackColor)userInfo:nil repeats:YES];

// 啟動

[timer fire];

// label背景顏色改變

NSTimer *timer2 =[NSTimerscheduledTimerWithTimeInterval:1/50.0 target:self selector:@selector(testChangeLableBackColor)userInfo:nil repeats:YES];

[timer2 fire];

}

-(void) testChangeLableBackColor

{

// 獲取背景色

UIColor *color = [self->_labelbackgroundColor];

const CGFloat *components = CGColorGetComponents(color.CGColor);

// 獲取RGB顏色

CGFloat red = components[0];

CGFloat green = components[1];

CGFloat blue =components[2];

// 這個是我調試出來的本來我是想讓它<255的 發現這樣出不來效果如果有誰知道是什麼意思求分享啊

// 我猜這個是讓 1.不是黑色的時候 2.以到達峰值不知道那個

if(red!=1)

{

// 設置標簽每次rgb+1 注意這裡傳入的時候不能帶有整數

// alpha:0.5 設置半透明

[self->_labelsetBackgroundColor:[UIColorcolorWithRed:red+1.0/255.0 green:green+1.0/255.0 blue:blue+1.0/255.0alpha:0.5]];

}

else

{

// 隨機RGB顏色前提要先有時間因子不然每次都是一樣

time(NULL);

CGFloat red = (CGFloat)random() / (CGFloat)RAND_MAX;

CGFloat green = (CGFloat)random() / (CGFloat)RAND_MAX;

CGFloat blue = (CGFloat)random() / (CGFloat)RAND_MAX;

[ self->_labelsetBackgroundColor:[UIColorcolorWithRed:red green:greenblue:blue alpha:0.5]];

}

}

-(void) testChangeViewBackColor

{

static BOOL seeded =NO;

if(!seeded)

{

seeded =YES;

time(NULL);

}

CGFloat red = (CGFloat)random() / (CGFloat)RAND_MAX;

CGFloat green = (CGFloat)random() / (CGFloat)RAND_MAX;

CGFloat blue = (CGFloat)random() / (CGFloat)RAND_MAX;

[ _myview setBackgroundColor:[UIColor colorWithRed:red green:green blue:blue alpha:1]];

}