IPHONE应用开发 - 开发常用控件：UIActionSheet和UIAlertView学习

iPhone开发常用控件UIActionSheet和UIAlertView的学习是本文要介绍的内容，主要来学习iphone开发中的控件如何来使用，来看本文详细内容。

一、UILabel

二、UIButton

常用事件：Touch Up Inside

三、UITextField

常用属性：

Text:要显示的文本。

Placeholder:指定将要在文本字段中以灰色显示的占位符文本。

Clear When Editing Begins:用户触摸此字段时是否删除字段中的值。

Text Input Traits:文本输入特征。

四、UIImageView

常用属性：

image:指定图像文件

Mode:图像在视图内部的对齐方式以及是否缩放图像以适应视图。选择任何图像缩放的选项都会潜在地增加处理开销，因此最好避开这些选项，并在导入图像之前调整好图像大小。通常Mode属性为Center。

Alpha：图像透明度。一般设置为1.0

Background:该属性继承自UIView，但它不会影响图像视图的外观，请忽略此属性。

Drawing复选框：选中Opaque表示视图后面的任何内容都不应该绘制，并且允许iPhone都绘图方法通过一些优化来加速绘图。

Clear Context Before Drawing:选中它之后，iPhone将使用透明黑色绘制控件覆盖都所有区域，然后才实际绘制控件。考虑到性能问题，并且适用情况很少，通常很少需要选中ClearContext Before Drawing。

Interaction复选框：

User Interaction Enabled:指定用户能否对此对象进行操作。

Multiple Touch：是否能够接收多点触摸事件。

五、UISlider(滑块)

常用属性：Value Changed

示例：

// 将silder的值反映到sliderLabel
- (IBAction) sliderValueChanged: (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];
}

六、UISwitch(开关)

代码

// 属性on：获取开关的状态是否为on// 方法setOn：设置开关的状态
- (IBAction) switchChanged: (id)sender{
UISwitch *whichSwitch = (UISwitch *)sender;
BOOL setting = whichSwitch.on;
[leftSwitch setOn:setting animated:YES];
[rightSwitch setOn:setting animated:YES];
}

七、UISegmentedControl

#define kSegmentIndex_Switches   0
#define kSegmentIndex_Button  1
- (IBAction) segmentChanged: (id)sender{
 switch ([sender selectedSegmentIndex])     {
   case kSegmentIndex_Switches:
    leftSwitch.hidden = NO;
    rightSwitch.hidden = NO;
    doSomethingButton.hidden = YES;
    break;
    case kSegmentIndex_Button: leftSwitch.hidden = YES;
    rightSwitch.hidden = YES;
     doSomethingButton.hidden = NO;  break;
  }
}

八、UIActionSheet（操作表）和UIAlertView（警报）

UIActionSheet用于迫使用户在两个或更多选项之间进行选择都模式视图。操作表从屏幕底部弹出，显示一系列按钮供用户选择，用户只有单击了一个按钮后才能继续使用使用应用程序。

UIAlertView（警报）以蓝色圆角矩形都形式出现在屏幕的中部，警报可显示一个或多个按钮。

为了让控制器类充当操作表的委托，控制器类需要遵从UIActionSheetDelegate协议。我们通过在类声明都超类之后都尖括号中添加协议名称来实现。

@interface UntitledViewController : UIViewController
<UIActionSheetDelegate>{    // ....}// 创建操作表：
- (IBAction) buttonPressed: (id)sender{
 UIActionSheet *actionSheet = [[UIActionSheet alloc]
 initWithTitle:@"Are you sure?" delegate:self
         cancelButtonTitle:@"Cancel"
         destructiveButtonTitle:@"Yes,I'm sure."
                      otherButtonTitles:nil];
   [actionSheet showInView:self.view];
   [actionSheet release];}// 实现方法：#pragma mark ActionSheet Delegate Methods
   - (void) actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex{
      if (buttonIndex != [actionSheet cancelButtonIndex])    {
        NSString *text = [[NSString alloc] initWithFormat:@"test alert"];
        UIAlertView *alert = [[UIAlertView alloc]
        initWithTitle:@"Something was done."
        message:text   delegate:self   cancelButtonTitle:@"OK!" ，otherButtonTitles:nil];
        [alert show];
        [alert release];
        [text release];
     }
 }//- (void) actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex//{//    NSLog(@"%d",buttonIndex);//}

示例

视图有一个UISegmentedControl,"Switches"下有两个UISwitch

"Button"下有一个“Do Something"的UIButton

触摸"Do Something"Button时弹出UIActionSheet

触摸选择"Yes,I'm sure."时弹出 UIAlertView

OBJECTIVE-C CODE   :UntitledViewController.h
 //
//  UntitledViewController.h
//  Untitled
//
//  Created by Elf Sundae on 11/10/10.
//  Copyright 2010 www.cnBlogs.com/ElfSundae. All rights reserved.
//

#import <UIKit/UIKit.h>

#define kSegmentIndex_Switches  0
#define kSegmentIndex_Button    1


@interface UntitledViewController : UIViewController
 <UIActionSheetDelegate>
{
 UISwitch * leftSwitch;
 UISwitch * rightSwitch;
 UIButton * doSomethingButton;
}

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

- (IBAction) switchChanged: (id)sender;
- (IBAction) segmentChanged: (id)sender;
- (IBAction) buttonPressed: (id)sender;

@end

//
//  UntitledViewController.h
//  Untitled
//
//  Created by Elf Sundae on 11/10/10.
//  Copyright 2010 www.cnBlogs.com/ElfSundae. All rights reserved.
//
#import <UIKit/UIKit.h>
#define kSegmentIndex_Switches  0
#define kSegmentIndex_Button  1
@interface UntitledViewController : UIViewController
 <UIActionSheetDelegate>
{
 UISwitch * leftSwitch;
 UISwitch * rightSwitch;
 UIButton * doSomethingButton;
}
@property (retain, nonatomic) IBOutlet UISwitch *leftSwitch;
@property (retain, nonatomic) IBOutlet UISwitch *rightSwitch;
@property (retain, nonatomic) IBOutlet UIButton *doSomethingButton;
- (IBAction) switchChanged: (id)sender;
- (IBAction) segmentChanged: (id)sender;
- (IBAction) buttonPressed: (id)sender;
@end

OBJECTIVE-C CODE   :UntitledViewController.m
 //
//  UntitledViewController.m
//  Untitled
//
//  Created by Elf Sundae on 11/10/10.
//  Copyright 2010 www.cnBlogs.com/ElfSundae. All rights reserved.
//

#import "UntitledViewController.h"

@implementation UntitledViewController

@synthesize leftSwitch;@synthesize rightSwitch;@synthesize doSomethingButton;// 属性on：获取开关的状态是否为on
// 方法setOn：设置开关的状态
- (IBAction) switchChanged: (id)sender{ UISwitch *whichSwitch = (UISwitch *)sender;
BOOL setting = whichSwitch.on;
[leftSwitch setOn:setting animated:YES];
[rightSwitch setOn:setting animated:YES];
}
- (IBAction) segmentChanged: (id)sender{
 switch ([sender selectedSegmentIndex])  {
 case kSegmentIndex_Switches:
   leftSwitch.hidden = NO;
   rightSwitch.hidden = NO;
   doSomethingButton.hidden = YES;
   break;
   case kSegmentIndex_Button:
   leftSwitch.hidden = YES;
   rightSwitch.hidden = YES;
   doSomethingButton.hidden = NO;
   break;
}
}
- (IBAction) buttonPressed: (id)sender{ UIActionSheet *actionSheet = [[UIActionSheet alloc]
 initWithTitle:@"Are you sure?"
      delegate:self  cancelButtonTitle:@"Cancel"
      destructiveButtonTitle:@"Yes,I'm sure."  otherButtonTitles:nil];
      [actionSheet showInView:self.view];
      [actionSheet release];
    }
  - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview.
 [super didReceiveMemoryWarning];
 // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload { // Release any retained subviews of the main view.
 // e.g. self.myOutlet = nil;
 self.leftSwitch = nil;
 self.rightSwitch = nil;
 self.doSomethingButton = nil;
 [super viewDidUnload];
}
 - (void)dealloc {
 [leftSwitch release];
 [rightSwitch release];
 [doSomethingButton release];
 [super dealloc];
}
#pragma mark
#pragma mark ActionSheet Delegate Methods
- (void) actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex{
if (buttonIndex != [actionSheet cancelButtonIndex]) {
 NSString *text = [[NSString alloc] initWithFormat:@"test alert"];
    UIAlertView *alert = [[UIAlertView alloc]
    initWithTitle:@"Something was done." message:text
    delegate:self
     cancelButtonTitle:@"OK!"  otherButtonTitles:nil];
     [alert show];
     [alert release];
     [text release];
   }
}//- (void) actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
//{
// NSLog(@"%d",buttonIndex);
//}
@end

小结：iPhone开发常用控件：UIActionSheet和UIAlertView学习的内容介绍完了，希望通过本文的学习能对你有所帮助！