本节采用代码的方式系统了解一下IOS主要UI控件的创建和使用，在开始之前首先要创建一个新的单页面IOS工程，这里我们的项目名称为baseUIs，将平台设置为ipad2（屏幕大），设置Main.storyboard中的主view的尺寸为iPad Full Screen。

1、屏幕布局
ipad2的屏幕分辨率为1024x768，为了合理使用界面，我们首先计划一下各个UI控件的摆放，我们假设每排放3个控件，计划放4排，采用如下的方式来摆放，这种方式要求我们通过UI空间的中心点来定位（另一种是通过左上角定位）。

我们首先在控制器头文件中采用宏定义的方式来定义这些坐标点，假设横排采用A、B、C、D命名，竖排采用1、2、3命名，命名如下：

#define A1 CGPointMake(192, 100)
#define A2 CGPointMake(384, 100)
#define A3 CGPointMake(576, 100)#define B1 CGPointMake(192, 300)
#define B2 CGPointMake(384, 300)
#define B3 CGPointMake(576, 300)#define C1 CGPointMake(192, 500)
#define C2 CGPointMake(384, 500)
#define C3 CGPointMake(576, 500)#define D1 CGPointMake(192, 700)
#define D2 CGPointMake(384, 700)
#define D3 CGPointMake(576, 700)

- (void)testWithTarget:(id)target{NSLog(@"%@ calls this method",[target class]);
}

#pragma mark -- UIButton按钮// 实例创建UIButton *newButton = [UIButton new];// 框架设置newButton.frame = CGRectMake(0, 0, 100, 100);newButton.center = A1;// 背景颜色newButton.backgroundColor=[UIColor lightGrayColor];// 按钮文字[newButton setTitle:@"ClickMe" forState:UIControlStateNormal];[newButton setTitle:@"Clicked" forState:UIControlStateHighlighted];// 文字颜色[newButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];[newButton setTitleColor:[UIColor whiteColor] forState:UIControlStateHighlighted];// 按钮图片[newButton setBackgroundImage:[UIImage imageNamed:@"01_btn_image1.png"] forState:UIControlStateNormal];[newButton setBackgroundImage:[UIImage imageNamed:@"01_btn_image2.png"] forState:UIControlStateHighlighted];// 监听设置[newButton addTarget:self action:@selector(testWithTarget:) forControlEvents:UIControlEventTouchUpInside];// 按钮添加[self.view addSubview:newButton];

该按钮控件需要调用两个用户自己定义的图片资源，我们需要加载到我们的项目，图片资源如下：

#pragma mark -- Label标签// 实例创建UILabel *newLabel=[UILabel new];// 框架设置newLabel.frame=CGRectMake(50, 100, 200, 100);newLabel.center = A2;// 标签文本newLabel.text=@"This is a label!";newLabel.tintColor=[UIColor redColor];// 标签背景颜色newLabel.backgroundColor=[UIColor lightGrayColor];// 自动换行newLabel.numberOfLines=0;// 标签添加[self.view addSubview:newLabel];

4、UITextField 控件

#pragma mark - UITextFieldDelegate
// 检测文本变动
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{NSLog(@"%@ shouldChangeCharactersInRange:{%d - %d}, replacementString:%@", textField.class, range.location, range.length, string);return YES;
};
// 监听编辑操作
- (void)textFieldDidBeginEditing:(UITextField *)textField{NSLog(@"%@ textFieldDidBeginEditing", textField.class);
}
// 监听编辑结束
- (void)textFieldDidEndEditing:(UITextField *)textField{NSLog(@"%@ textFieldDidEndEditing", textField.class);
}
// 编辑之前执行的操作
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{NSLog(@"%@ textFieldShouldBeginEditing", textField.class);return YES;
}
// 清空之前执行
- (BOOL)textFieldShouldClear:(UITextField *)textField{NSLog(@"%@ textFieldShouldClear", textField.class);return YES;
}
// 编辑完成前执行
- (BOOL)textFieldShouldEndEditing:(UITextField *)textField{NSLog(@"%@ textFieldShouldEndEditing", textField.class);return YES;
}
// 回车键方法（主要用在iphone，在ipad中有隐去键盘键）
- (BOOL)textFieldShouldReturn:(UITextField *)textField{// 放弃焦点，隐藏键盘[textField resignFirstResponder];return YES;
}

#pragma mark -- UITextFeild文本框// 文本框实例化UITextField *newTextField = [UITextField new];// 框架设置newTextField.frame = CGRectMake(0, 0, 150, 70);newTextField.center = A3;// 样式newTextField.borderStyle = UITextBorderStyleBezel;// 文字提示newTextField.placeholder = @"Insert some text!";// 清除按钮newTextField.clearButtonMode = UITextFieldViewModeWhileEditing;// 键盘样式newTextField.keyboardType = UIKeyboardTypeDefault;newTextField.returnKeyType = UIReturnKeyDone;// 代理设置newTextField.delegate=self;// 文本框添加[self.view addSubview:newTextField];

5、UITextView 控件

#pragma mark - UITextViewDelegate
// 文本变化
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{NSLog(@"%@ shouldChangeCharactersInRange:{%d - %d}, replacementString:%@", textView.class, range.location, range.length, text);return YES;
}
// 导入富文本（图文）
- (BOOL)textView:(UITextView *)textView shouldInteractWithTextAttachment:(NSTextAttachment *)textAttachment inRange:(NSRange)characterRange{NSLog(@"%@ shouldInteractWithTextAttachment:%@, inRange:{%d - %d} ",textView.class, textAttachment, characterRange.location, characterRange.length);return YES;
}
// 网络导入数据
- (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)URL inRange:(NSRange)characterRange{return YES;
}
// 开始编辑时执行
- (void)textViewDidBeginEditing:(UITextView *)textView{NSLog(@"%@ textViewDidBeginEditing", textView.class);
}
// 文本变化监听
- (void)textViewDidChange:(UITextView *)textView{NSLog(@"%@ textViewDidChange", textView.class);
}
// 文本选择变更
- (void)textViewDidChangeSelection:(UITextView *)textView{NSLog(@"%@ textViewDidChangeSelection", textView.class);
}
// 编辑结束触发
- (void)textViewDidEndEditing:(UITextView *)textView{NSLog(@"%@ textViewDidEndEditing", textView.class);
}
// 编辑前预处理
- (BOOL)textViewShouldBeginEditing:(UITextView *)textView{NSLog(@"%@ textViewShouldBeginEditing", textView.class);return YES;
}
// 编辑结束预处理
- (BOOL)textViewShouldEndEditing:(UITextView *)textView{NSLog(@"%@ textViewShouldEndEditing", textView.class);return YES;
}

代码创建文本编辑框：

#pragma mark -- UITextView文本区域// 文本创建UITextView *newTextView = [UITextView new];newTextView.frame = CGRectMake(0, 0, 200, 200);newTextView.center = B1;// 文本样式newTextView.backgroundColor = [UIColor lightGrayColor];// 文字样式newTextView.font = [UIFont fontWithName:@"Arial" size:20];newTextView.textColor = [UIColor purpleColor];// 文字内容newTextView.text = @"Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.";// 键盘样式newTextView.keyboardType = UIKeyboardTypeDefault;// 设置代理newTextView.delegate = self;// 添加文本[self.view addSubview:newTextView];

6、UIImage 控件

#pragma mark -- UIImageView图片框// 图片框创建UIImageView *newImageView = [UIImageView new];newImageView.frame = CGRectMake(0, 0, 100, 200);newImageView.center = B2;// 加载图片newImageView.image = [UIImage imageNamed:@"02_image.jpg"];// 图片样式newImageView.contentMode = UIViewContentModeScaleAspectFill;// 图片框添加[self.view addSubview:newImageView];

在这里使用到了一个图片资源，他的使用方法和按钮图片的使用方法一样，放在工程中即可。

#pragma mark -- UISlider滑块// 滑块创建UISlider *newSlider = [UISlider new];newSlider.frame = CGRectMake(0, 0, 100, 30);newSlider.center = B3;// 数值范围newSlider.minimumValue = 0;newSlider.maximumValue = 9;// 监听滑块[newSlider addTarget:self action:@selector(testWithTarget:) forControlEvents:UIControlEventValueChanged];// 添加滑块[self.view addSubview:newSlider];

8、UISwitch 控件

#pragma mark -- UISwitch开关// 开关创建UISwitch *newSwitch = [UISwitch new];newSwitch.center = C1;// 开关样式newSwitch.thumbTintColor = [UIColor purpleColor];newSwitch.tintColor = [UIColor redColor];// 监听开关[newSwitch addTarget:self action:@selector(testWithTarget:) forControlEvents:UIControlEventValueChanged];// 添加开关[self.view addSubview:newSwitch];

9.UISegmentControl 控件

#pragma mark -- UISegmentedControl分段控制器// 实例创建UISegmentedControl *newSegment = [UISegmentedControl new];// 框架设置newSegment.frame = CGRectMake(0, 0, 150, 50);newSegment.center = C2;// 内容添加[newSegment insertSegmentWithTitle:@"Seg3" atIndex:0 animated:NO];[newSegment insertSegmentWithTitle:@"Seg2" atIndex:0 animated:NO];[newSegment insertSegmentWithTitle:@"Seg1" atIndex:0 animated:NO];[newSegment insertSegmentWithTitle:@"Seg0" atIndex:0 animated:NO];// 样式设置newSegment.backgroundColor = [UIColor blackColor];newSegment.tintColor = [UIColor lightGrayColor];// 初始位置newSegment.selectedSegmentIndex = 0;// 监听设置[newSegment addTarget:self action:@selector(testWithTarget:) forControlEvents:UIControlEventValueChanged];// 添加到视图[self.view addSubview:newSegment];

- (void)testWithTarget:(id)target{Class class = [target class];// 根据不同对象输出不同的参数if (class == [UIButton class]) {NSLog(@"%@ calls this method", class);}else if (class == [UISlider class]){NSLog(@"%@ calls this method, currentValue: %f", class, [(UISlider*)target value]);}else if (class == [UISegmentedControl class]){NSLog(@"%@ calls this method, selectedSegmentIndex: %d", class, [(UISegmentedControl*)target selectedSegmentIndex]);}else if(class == [UISwitch class]){NSLog(@"%@ calls this method, currentState: %d", class, [(UISwitch*)target isOn]);}}

现在我们可以执行查看运行效果，并通过界面操作来熟悉各种事件监听的机制（包括代理方法的响应），这些方法都会将调用信息反馈到调试窗口中，程序的最终运行效果如下：

selectedSegmentIndex