IOS开发（13）之UITextField控件

本文主要是介绍IOS开发（13）之UITextField控件，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

1 前言

UITextField用来接受用户输入的文本，在开发中十分常见，今天我们来学习一下该控件。

2 代码实例

ZYViewController.h：

#import <UIKit/UIKit.h>@interface ZYViewController : UIViewController@property (nonatomic,strong)UITextField *myTextField;@end

ZYViewController.m：

@synthesize myTextField;- (void)viewDidLoad
{[super viewDidLoad];// Do any additional setup after loading the view, typically from a nib.self.view.backgroundColor = [UIColor whiteColor];CGRect textFieldFrame = CGRectMake(0.0f, 0.0f, 200.0f, 31.0f);self.myTextField = [[UITextField alloc] initWithFrame:textFieldFrame];//绘制控件模型self.myTextField.borderStyle = UITextBorderStyleRoundedRect;//设置如何显示边框self.myTextField.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;//设置纵向居中self.myTextField.textAlignment = UITextAlignmentCenter;//设置水平居中self.myTextField.text = @"Sir Archy Develop_Zhang";//设置输入框内容self.myTextField.center = self.view.center;//设置UITextField位置[self.view addSubview:self.myTextField];
}

ZYUITextFieldViewController.h：

#import <UIKit/UIKit.h>@interface ZYUITextFieldViewController : UIViewController<UITextFieldDelegate>@property(nonatomic,strong) UITextField *myTextField;@property(nonatomic,strong) UILabel *labelCounter;@end

ZYUITextFieldViewController.m：

@synthesize myTextField;@synthesize labelCounter;- (void)viewDidLoad
{[super viewDidLoad];// Do any additional setup after loading the view.self.view.backgroundColor = [UIColor whiteColor];CGRect textFieldFrame = CGRectMake(38.0f, 30.0f, 220.0f, 31.0f);self.myTextField = [[UITextField alloc] initWithFrame:textFieldFrame];self.myTextField.delegate = self;self.myTextField.borderStyle = UITextBorderStyleRoundedRect;self.myTextField.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
//    self.myTextField.text = @"Sir Archy Developer_Zhang";self.myTextField.placeholder = @"Enter text here......";//当UITextField里面没有字符的时候，默认显示的内容[self.view addSubview:myTextField];CGRect labelCounterFrame = self.myTextField.frame;labelCounterFrame.origin.y += textFieldFrame.size.height+10;self.labelCounter = [[UILabel alloc] initWithFrame:labelCounterFrame];[self.view addSubview:labelCounter];[self calculateAndDisplayTextFieldLengthWithText:self.myTextField.text];UILabel *currencyLabel = [[UILabel alloc] initWithFrame:CGRectZero];//CGRectZero相当于CGRectMake(0,0,0,0)currencyLabel.text = [[[NSNumberFormatter alloc] init] currencySymbol];//初始化Label内容返回接受者的本地货币符号currencyLabel.font = self.myTextField.font;[currencyLabel sizeToFit];//调整和移动接收者的视图,它只是包含它自己的视图。self.myTextField.leftView = currencyLabel;self.myTextField.leftViewMode = UITextFieldViewModeAlways;//设置左视图一直显示/*typedef enum{UITextFieldViewModeNever,//从不显示UITextFieldViewModeWhileEditing,//编辑时候显示UITextFieldViewModeUnlessEditing,//编辑结束时候显示UITextFieldViewModeAlways//一直显示}UITextFieldViewMode;*/}//计算UITextField里面字符的长度
-(void)calculateAndDisplayTextFieldLengthWithText:(NSString *)paramText{NSString *characterOrCharacters = @"Characters";if ([paramText length]==1) {characterOrCharacters = @"Character";}self.labelCounter.text = [NSString stringWithFormat:@"%lu %@",(unsigned long)[paramText length],characterOrCharacters];
}//当UITextField输入文字后触发的事件
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{BOOL result = YES;if ([textField isEqual:self.myTextField]) {NSString *wholeText = [textField.text stringByReplacingCharactersInRange:range withString:string];//追加后输入的字符串[self calculateAndDisplayTextFieldLengthWithText:wholeText];//重新计算字符长度}return result;
}
//当单击返回按钮触发的事件
-(BOOL)textFieldShouldReturn:(UITextField *)textField{[textField resignFirstResponder];//关闭键盘return YES;
}

运行结果：