IOS timer NSTimer random acquisition color acquisition and setting RGB view background color

-(Void) viewDidLoad

{

[Super viewDidLoad];

// Label initialization color

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

// View background color change

// 1/20. 0. The error may occur once if the execution is performed 20 times in one second.

NSTimer * timer = [NSTimerscheduledTimerWithTimeInterval: 1/20. 0 target: self selector: @ selector (testChangeViewBackColor) userInfo: nilrepeats: YES];

// Start

[Timer fire];

// The label background color changes.

NSTimer * timer2 = [NSTimerscheduledTimerWithTimeInterval: 1/50. 0 target: self selector: @ selector (testChangeLableBackColor) userInfo: nilrepeats: YES];

[Timer2 fire];

}

-(Void) testChangeLableBackColor

{

// Obtain the background color

UIColor * color = [self-> _ labelbackgroundColor];

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

// Obtain the RGB color

CGFloat red = components [0];

CGFloat green = components [1];

CGFloat blue = components [2];

// This is what I debugged. Originally, I wanted to make it <255 discover this effect. If anyone knows what it means, share it with me.

// I guess this is to make 1. When it is not black 2. I don't know

If (red! = 1)

{

// Set the label. Each time rgb + 1 is passed in, the label cannot contain an integer.

// Alpha: 0.5 sets translucent

[Self-> _ labelsetBackgroundColor: [UIColorcolorWithRed: red + 1.0/255.0 green: green + 1.0/255.0 blue: blue + 1.0/255.0 alpha: 0.5];

}

Else

{

// A time factor must be set before the random RGB color is specified. Otherwise, each time is the same.

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: redgreen: greenblue: bluealpha: 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];

}