ios學習筆記（三）UISlider與UISwitch控制項

1 首先我們還是建立一個Single View Application，然後開啟MainStoryboard_iphone.storyboard,在IB中添加一個UISlider控制項和一個Label，這個Label用來顯示Slider的值。

選中新加的Slider控制項，開啟Attribute Inspector，修改屬性值，設定最小值為0，最大值為100，當前值為0.5，並確保勾選上Continuous，如：

接著我們放上UISwitch控制項，就是很像開關的那種控制項，它只有兩個狀態：on和off，全都放上去效果就是這樣的：

2.好了我們開始寫代碼嘍：ViewController.h：

#import <UIKit/UIKit.h>@interface ViewController : UIViewController{    UILabel *sliderlabel;    UISwitch *leftSwitch;    UISwitch *rightSwitch;}@property (nonatomic,retain) IBOutlet UILabel *sliderlabel;@property (nonatomic,retain) IBOutlet UISwitch *leftSwitch;@property (nonatomic,retain) IBOutlet UISwitch *rightSwitch;- (IBAction)sliderChanged:(id)sender;- (IBAction)switchChanged:(id)sender;@end

接著是實現 ViewController.m:

#import "ViewController.h"@interface ViewController ()@end@implementation ViewController@synthesize sliderlabel;@synthesize leftSwitch;@synthesize rightSwitch;- (void)viewDidLoad{    [super viewDidLoad];// Do any additional setup after loading the view, typically from a nib.}- (void)viewDidUnload{    [super viewDidUnload];    // Release any retained subviews of the main view.}- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {        return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);    } else {        return YES;    }}- (IBAction)sliderChanged:(id)sender{    UISlider *slider=(UISlider*)sender;    int progressAsInt=(int)(slider.value+0.5f);    NSString *newText=[[NSString alloc] initWithFormat:@"%d",progressAsInt];    sliderlabel.text=newText;    [newText release];    NSLog(@"%d",progressAsInt);}- (IBAction)switchChanged:(id)sender{    UISwitch *whichSwich=(UISwitch *)sender;    BOOL setting=whichSwich.isOn;    [leftSwitch setOn:setting animated:YES];    [rightSwitch setOn:setting animated:YES];}- (void)dealloc{    [sliderlabel release];    [leftSwitch release];    [rightSwitch release];    [super dealloc];}@end

3.剩下的就是串連操作和輸出口：

將slider控制項的value changed事件與sliderChanged方法串連在一起，將swich控制項的value changed事件與swichChanged方法串連在一起，當然還要把lable控制項和swich控制項的輸出與ViewController的相應控制項介面串連在一起。

最終實現的效果如下面兩張圖：