学步园

iphone与android一样都包含一些常见的控件比如按钮，图片控件（ImageView）、TableViewController（android下为listView）、标签（android下为TextView）、进度条等。今天我们就来学习一下这些控件的使用。

新建一个基于View的项目，添加下图中的控件

我们添加了Label、TextField、Slider、SwitchButton、ToggleButton控件。下面我们需要为TextField和Label控件（显示Slider值的控件图中35）设置输出口以及为按钮设置事件监听。不要忘了将控件与输出口及事件建立连接，方法：按住Control从File's owner 拖到控件，这时会弹出相关的输出口或事件。

在ViewController文件中加入一下代码：

<UIActionSheetDelegate>
{
    
}

@property (nonatomic, retain) IBOutlet UITextField *nameField;

@property (nonatomic, retain) IBOutlet UITextField *passField;

@property (nonatomic, retain) IBOutlet UILabel *sliderLabel;

@property (nonatomic, retain) IBOutlet UISwitch *leftSwitch;
@property (nonatomic, retain) IBOutlet UISwitch *rightSwitch;
@property (nonatomic, retain) IBOutlet UIButton *doSomethingBtn;

- (IBAction)toggleControls:(id)sender;
- (IBAction)switchChanged:(id)sender;
- (IBAction)buttonPressed:(id)sender;
- (IBAction)textFieldDoneEditing:(id)sender;
- (IBAction)backgroundTap:(id)sender;
- (IBAction)sliderChanged:(id)sender;

修改ViewController.m文件如下：

#import "ViewController.h"

@implementation ViewController
@synthesize nameField;
@synthesize passField;
@synthesize sliderLabel;
@synthesize leftSwitch;
@synthesize rightSwitch;
@synthesize doSomethingBtn;
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Release any cached data, images, etc that aren't in use.
}

- (IBAction)toggleControls:(id)sender
{
    if([sender selectedSegmentIndex] == kSwichesSegmentIndex){
        leftSwitch.hidden = NO;
        rightSwitch.hidden = NO;
        doSomethingBtn.hidden = YES;
    }else{
        leftSwitch.hidden = YES;
        rightSwitch.hidden = YES;
        doSomethingBtn.hidden = NO;
    }
}

- (IBAction)switchChanged:(id)sender
{
    UISwitch *whichSwitch = (UISwitch *)sender;
    BOOL setting = whichSwitch.isOn;
    [leftSwitch setOn:setting animated:YES];
    [rightSwitch setOn:setting animated:YES];
}

- (IBAction)buttonPressed:(id)sender
{
    UIActionSheet *actionSheet = [[UIActionSheet alloc] 
                                  initWithTitle:@"Are you sure?" 
                                  delegate:self
                                  cancelButtonTitle:@"No way!"
                                  destructiveButtonTitle:@"Yes,I'm sure!"
                                  otherButtonTitles:nil, nil];
    [actionSheet showInView:self.view];
    [actionSheet release];
}

- (void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex
{
    if (buttonIndex != [actionSheet cancelButtonIndex]) {
        NSString *msg = nil;
        if (nameField.text.length > 0) {
            msg = [[NSString alloc] initWithFormat:@"You can breathe easy, %@, everything went OK.", nameField.text];
        }else{
            msg = @"You can breathe easy, everything went Ok.";
        }
        UIAlertView *alert = [[UIAlertView alloc] 
                              initWithTitle:@"Something was done" 
                              message:msg 
                              delegate:self 
                              cancelButtonTitle:@"Phew!" 
                              otherButtonTitles:nil, nil];
        [alert show];
        [alert release];
        [msg release];
    }
    
}
- (IBAction)textFieldDoneEditing:(id)sender
{
    [sender resignFirstResponder];  //Hidden keyboard
}

- (IBAction)backgroundTap:(id)sender
{
    [nameField resignFirstResponder];
    [passField resignFirstResponder];
}

- (IBAction)sliderChanged:(id)sender
{
    UISlider *slider = (UISlider *)sender;
    int progress = (int)slider.value;
    NSString *labelText = [[NSString alloc] initWithFormat:@"%d",progress];
    sliderLabel.text = labelText;
    [labelText release];
}
#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
}

- (void)viewDidUnload
{
    self.nameField = nil;
    self.passField = nil;
    self.sliderLabel = nil;
    self.leftSwitch = nil;
    self.rightSwitch = nil;
    self.doSomethingBtn = nil;
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

- (void)viewWillDisappear:(BOOL)animated
{
	[super viewWillDisappear:animated];
}

- (void)viewDidDisappear:(BOOL)animated
{
	[super viewDidDisappear:animated];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
        return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
    } else {
        return YES;
    }
}
- (void) dealloc
{
    [nameField release];
    [passField release];
    [sliderLabel release];
    [leftSwitch release];
    [rightSwitch release];
    [doSomethingBtn release];
    [super dealloc];
}
@end

- (IBAction)toggleControls:(id)sender    当ToggleButton按钮按下时，另外一个按钮设置为同样的状态。
- (IBAction)switchChanged:(id)sender  该事件处理Switch按钮事件，隐藏toggle按钮。
- (IBAction)buttonPressed:(id)sender    当toggle隐藏button显示时，响应Button事件。
- (IBAction)textFieldDoneEditing:(id)sender;     隐藏输入面板，当用户按下输入法Done按钮时

- (IBAction)backgroundTap:(id)sender    隐藏输入法，但用户点击程序任意位置时
- (IBAction)sliderChanged:(id)sender;    当Slider值改变时，Label的text设置为Slider的Value。

到此我们对一些常用的小控件有了一定的了解，接下来我们将学习TableView控件，相当于android平台的ListView控件。

好了就写这么多，有什么问题请留言，大家一起学习交流！

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