iOS开发中UISwitch按钮的使用方法简介

一、第一种创建UISwitch控件的方法，在代码中动态创建。
1、打开Xcode  4.3.2, 新建项目Switch，选择Single View Application。
2、打开ViewController.m文件在viewDidLoad方法里添加代码：

代码如下:

- (void)viewDidLoad
{
    [super viewDidLoad];
    UISwitch *switchButton = [[UISwitch alloc] initWithFrame:CGRectMake(50, 100, 20, 10)];
    [switchButton setOn:YES];
    [switchButton addTarget:self action:@selector(switchAction:) forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:switchButton];
   
 // Do any additional setup after loading the view, typically from a nib.
}

代码中selector中的switchAction：需要我们自己实现，就是按下时接收到的事件。
记得把switchButton加到当前view，调用[self.viewaddSubview:switchButton];
3、监听UISwitch按下事件
实现代码如下：

代码如下:

-(void)switchAction:(id)sender
{
    UISwitch *switchButton = (UISwitch*)sender;
    BOOL isButtonOn = [switchButton isOn];
    if (isButtonOn) {
        showSwitchValue.text = @"是";
    }else {
        showSwitchValue.text = @"否";
    }
}

showSwitchValue是我通过拖拽控件方法放到界面上的Label，方便显示效果
运行，效果：

二、通过拖拽方法使用UISwitch
1、往xib文件上拖拽一个UISwitch控件。

2、按alt+command + return键开启Assistant Editor模式，选中UISwitch控件，按住Control键，往ViewController.h拖拽

3、选Action方式

4、.m文件中实现switchAction 。刚才动态创建的时候也用到这个方法名称，可以先注释掉刚才的。

代码如下:

- (IBAction)switchAction:(id)sender {
    UISwitch *switchButton = (UISwitch*)sender;
    BOOL isButtonOn = [switchButton isOn];
    if (isButtonOn) {
        showSwitchValue.text = @"是";
    }else {
        showSwitchValue.text = @"否";
    }
}

这里我们来看一下.m文件的源码：

代码如下:

#import "HMCustomSwitch.h"

@implementation HMCustomSwitch

@synthesize on;
@synthesize tintColor, clippingView, leftLabel, rightLabel;

+(HMCustomSwitch *)switchWithLeftText:(NSString *)leftText andRight:(NSString *)rightText
{
 HMCustomSwitch *switchView = [[HMCustomSwitch alloc] initWithFrame:CGRectZero];
 
 switchView.leftLabel.text = leftText;
 switchView.rightLabel.text = rightText;
 
 return [switchView autorelease];
}

-(id)initWithFrame:(CGRect)rect
{
 if ((self=[super initWithFrame:CGRectMake(rect.origin.x,rect.origin.y,95,27)]))
 {
  //  self.clipsToBounds = YES;
  
  [self awakeFromNib];  // do all setup in awakeFromNib so that control can be created manually or in a nib file
 }
 return self;
}

-(void)awakeFromNib
{
 [super awakeFromNib];
 
 self.backgroundColor = [UIColor clearColor];

[self setThumbImage:[UIImage imageNamed:@"switchThumb.png"] forState:UIControlStateNormal];
 [self setMinimumTrackImage:[UIImage imageNamed:@"switchBlueBg.png"] forState:UIControlStateNormal];
 [self setMaximumTrackImage:[UIImage imageNamed:@"switchOffPlain.png"] forState:UIControlStateNormal];
 
 self.minimumValue = 0;
 self.maximumValue = 1;
 self.continuous = NO;
 
 self.on = NO;
 self.value = 0.0;
 
 self.clippingView = [[UIView alloc] initWithFrame:CGRectMake(4,2,87,23)];
 self.clippingView.clipsToBounds = YES;
 self.clippingView.userInteractionEnabled = NO;
 self.clippingView.backgroundColor = [UIColor clearColor];
 [self addSubview:self.clippingView];
 [self.clippingView release];
 
 NSString *leftLabelText = NSLocalizedString(@"ON","Custom UISwitch ON label. If localized to empty string then I/O will be used");
 if ([leftLabelText length] == 0) 
 {
  leftLabelText = @"l";  // use helvetica lowercase L to be a 1.
 }
 
 self.leftLabel = [[UILabel alloc] init];
 self.leftLabel.frame = CGRectMake(0, 0, 48, 23);
 self.leftLabel.text = leftLabelText;
 self.leftLabel.textAlignment = NSTextAlignmentCenter;
 self.leftLabel.font = [UIFont boldSystemFontOfSize:17];
 self.leftLabel.textColor = [UIColor whiteColor];
 self.leftLabel.backgroundColor = [UIColor clearColor];
 //  self.leftLabel.shadowColor = [UIColor redColor];
 //  self.leftLabel.shadowOffset = CGSizeMake(0,0);
 [self.clippingView addSubview:self.leftLabel];
 [self.leftLabel release];
 
 
 NSString *rightLabelText = NSLocalizedString(@"OFF","Custom UISwitch OFF label. If localized to empty string then I/O will be used");
 if ([rightLabelText length] == 0) 
 {
  rightLabelText = @"O"; // use helvetica uppercase o to be a 0.
 }
 
 self.rightLabel = [[UILabel alloc] init];
 self.rightLabel.frame = CGRectMake(95, 0, 48, 23);
 self.rightLabel.text = rightLabelText;
 self.rightLabel.textAlignment = NSTextAlignmentCenter;
 self.rightLabel.font = [UIFont boldSystemFontOfSize:17];
 self.rightLabel.textColor = [UIColor grayColor];
 self.rightLabel.backgroundColor = [UIColor clearColor];
 //  self.rightLabel.shadowColor = [UIColor redColor];
 //  self.rightLabel.shadowOffset = CGSizeMake(0,0);
 [self.clippingView addSubview:self.rightLabel];
 [self.rightLabel release];
 
 
}

-(void)layoutSubviews
{
 [super layoutSubviews];
 
 // NSLog(@"leftLabel=%@",NSStringFromCGRect(self.leftLabel.frame));
 
 // move the labels to the front
 [self.clippingView removeFromSuperview];
 [self addSubview:self.clippingView];
 
 CGFloat thumbWidth = self.currentThumbImage.size.width;
 CGFloat switchWidth = self.bounds.size.width;
 CGFloat labelWidth = switchWidth - thumbWidth;
 CGFloat inset = self.clippingView.frame.origin.x;
 
 // NSInteger xPos = self.value * (self.bounds.size.width - thumbWidth) - (self.leftLabel.frame.size.width - thumbWidth/2);
 NSInteger xPos = self.value * labelWidth - labelWidth - inset;
 self.leftLabel.frame = CGRectMake(xPos, 0, labelWidth, 23);
 
 // xPos = self.value * (self.bounds.size.width - thumbWidth) + (self.rightLabel.frame.size.width - thumbWidth/2);
 xPos = switchWidth + (self.value * labelWidth - labelWidth) - inset;
 self.rightLabel.frame = CGRectMake(xPos, 0, labelWidth, 23);
 
 // NSLog(@"value=%f    xPos=%i",self.value,xPos);
 // NSLog(@"thumbWidth=%f    self.bounds.size.width=%f",thumbWidth,self.bounds.size.width);
}

- (UIImage *)image:(UIImage*)image tintedWithColor:(UIColor *)tint
{ 
 
    if (tint != nil)
 {
  UIGraphicsBeginImageContext(image.size);
  
  //draw mask so the alpha is respected
  CGContextRef currentContext = UIGraphicsGetCurrentContext();
  CGImageRef maskImage = [image CGImage];
  CGContextClipToMask(currentContext, CGRectMake(0, 0, image.size.width, image.size.height), maskImage);
  CGContextDrawImage(currentContext, CGRectMake(0,0, image.size.width, image.size.height), image.CGImage);
  
  [image drawAtPoint:CGPointMake(0,0)];
  [tint setFill];
  UIRectFillUsingBlendMode(CGRectMake(0,0,image.size.width,image.size.height),kCGBlendModeColor);
  UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  
        return newImage;
    }
    else
 {
        return image;
    }
}

-(void)setTintColor:(UIColor*)color
{
 if (color != tintColor)
 {
  [tintColor release];
  tintColor = [color retain];
  
  [self setMinimumTrackImage:[self image:[UIImage imageNamed:@"switchBlueBg.png"] tintedWithColor:tintColor] forState:UIControlStateNormal];
 }
 
}

- (void)setOn:(BOOL)turnOn animated:(BOOL)animated;
{
 on = turnOn;
 
 if (animated)
 {
  [UIView  beginAnimations:nil context:nil];
  [UIView setAnimationDuration:0.2];
 }
 
 if (on)
 {
  self.value = 1.0;
 }
 else
 {
  self.value = 0.0;
 }
 
 if (animated)
 {
  [UIView commitAnimations]; 
 }
}

- (void)setOn:(BOOL)turnOn
{
 [self setOn:turnOn animated:NO];
}

- (void)endTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event
{
 NSLog(@"preendTrackingWithtouch");
 [super endTrackingWithTouch:touch withEvent:event];
 NSLog(@"postendTrackingWithtouch");
 m_touchedSelf = YES;
 
 [self setOn:on animated:YES];
}

- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
 [super touchesBegan:touches withEvent:event];
  NSLog(@"touchesBegan");
 m_touchedSelf = NO;
 on = !on;
}

- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event
{
 [super touchesEnded:touches withEvent:event];
 NSLog(@"touchesEnded");
 
 if (!m_touchedSelf)
 {
  [self setOn:on animated:YES];
  [self sendActionsForControlEvents:UIControlEventValueChanged];
 }
}

-(void)dealloc
{
 [tintColor release];
 [clippingView release];
 [rightLabel release];
 [leftLabel release];
 
 [super dealloc];
}

@end

看代码可以知道，其实它是通过继承UISlider控件实现的，UISlider的左右分别是个UILabel，当YES的时候，滑块滑到了最右边，NO的时候滑到了最左边。
所以在代码中使用它呢？这里再举一个例子：

代码如下:

- (void)loadView
{
 UIView *contentView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
 self.view = contentView;
 contentView.backgroundColor = [UIColor whiteColor];
 
 // Standard ON/OFF
 HMCustomSwitch *switchView = [[HMCustomSwitch alloc] initWithFrame:CGRectZero];
 switchView.center = CGPointMake(160.0f, 20.0f);
 switchView.on = YES;
 [contentView addSubview:switchView];
 [switchView release];
 
 // Custom YES/NO
 switchView = [HMCustomSwitch switchWithLeftText:@"YES" andRight:@"NO"];
 switchView.center = CGPointMake(160.0f, 60.0f);
 switchView.on = YES;
 [contentView addSubview:switchView];
 
 // Custom font and color
 switchView = [HMCustomSwitch switchWithLeftText:@"Hello " andRight:@"ABC "];
 switchView.center = CGPointMake(160.0f, 100.0f);
 switchView.on = YES;
 [switchView.leftLabel setFont:[UIFont boldSystemFontOfSize:13.0f]];
 [switchView.rightLabel setFont:[UIFont italicSystemFontOfSize:15.0f]];
 [switchView.rightLabel setTextColor:[UIColor blueColor]];
 [contentView addSubview:switchView];
 
 // Multiple lines
 switchView = [HMCustomSwitch switchWithLeftText:@"Hello\nWorld" andRight:@"Bye\nWorld"];
 switchView.center = CGPointMake(160.0f, 140.0f);
 switchView.on = YES;
 switchView.tintColor = [UIColor orangeColor];
 switchView.leftLabel.font = [UIFont boldSystemFontOfSize:9.0f];
 switchView.rightLabel.font = [UIFont boldSystemFontOfSize:9.0f];
 switchView.leftLabel.numberOfLines = 2;
 switchView.rightLabel.numberOfLines = 2;
 switchView.leftLabel.lineBreakMode = NSLineBreakByWordWrapping;
 switchView.rightLabel.lineBreakMode = NSLineBreakByWordWrapping;
 [contentView addSubview:switchView];
 
 switchView = [[HMCustomSwitch alloc] init];
 switchView.center = CGPointMake(160.0f, 180.0f);
 switchView.on = YES;
 switchView.tintColor = [UIColor purpleColor];
 [contentView addSubview:switchView];
 [switchView release];
 
 switchView = [HMCustomSwitch switchWithLeftText:@"l" andRight:@"O"];
 switchView.center = CGPointMake(160.0f, 220.0f);
// customSwitch.tintColor = [UIColor colorWithRed:125.f/255.f green:157.f/255.f blue:93.f/255.f alpha:1.0];
// customSwitch.tintColor = [UIColor colorWithRed:125.f/255.f green:157.f/255.f blue:93.f/255.f alpha:1.0];
 [contentView addSubview:switchView];

// Standard ON/OFF
 switchView = [[HMCustomSwitch alloc] init];
 switchView.center = CGPointMake(160.0f, 260.0f);
 switchView.tintColor = [UIColor colorWithRed:125.f/255.f green:157.f/255.f blue:93.f/255.f alpha:1.0];
 [switchView addTarget:self action:@selector(switchFlipped:) forControlEvents:UIControlEventValueChanged];
 [contentView addSubview:switchView];
 [switchView release];
 
 
 
 UIToolbar *toolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 420, 320, 40)];
 toolbar.tintColor = [UIColor colorWithRed:125.f/255.f green:157.f/255.f blue:93.f/255.f alpha:1.0];
 [contentView addSubview:toolbar];
 
 [contentView release];
}

-(void)switchFlipped:(HMCustomSwitch*)switchView
{
 NSLog(@"switchFlipped=%f  on:%@",switchView.value, (switchView.on?@"Y":@"N"));
 
}