xcode 6.1

File-New-Project..

iOs-Application-Simple View Application

1、写一个自定义JSTextField类，继承UITextField,来重载原有的initWithFrame方法，以便以后可以重用。

1.1右键，弹的菜单New File...

1.2 iOS-Source-Cocoa Touch Class

1.3 在Class:中输入JSTextField(名字自取),让其继承UITextField:

1.4 Next =>Create 创建文件JSTextField.h JSTextField.m

1.5 点击JSTextField.h,输入方法：

代码：

-(id)initWithFrame:(CGRect)frame drawingLeft:(UIImageView*)icon;

1.6 打开JSTextField.m,实现initWithFrame方法，并且overwrite方法leftViewRectForBounds:,让图标右侧可以有点间距:

代码：

#import "JSTextField.h"@implementation JSTextField-(id)initWithFrame:(CGRect)frame drawingLeft:(UIImageView *)icon{    self = [super initWithFrame:frame];    if (self) {        self.leftView = icon;        self.leftViewMode = UITextFieldViewModeAlways;    }    return self;}-(CGRect)leftViewRectForBounds:(CGRect)bounds{    CGRect iconRect = [super leftViewRectForBounds:bounds];    iconRect.origin.x += 10;// 右偏10    return iconRect;}@end

2、使用刚才的JSTextField:

代码：

UIImage *usernameImage = [UIImage imageNamed:@"20.gif"];    UIImageView *usernameIcon = [[UIImageView alloc] initWithImage:usernameImage];    usernameIcon.frame = CGRectMake(0, 0, 20, 20);        self.textview = [[JSTextField alloc] initWithFrame:CGRectMake(0, 200, 240, 30) drawingLeft:usernameIcon];    self.textview.placeholder = @"用户名";    self.textview.borderStyle = UITextBorderStyleRoundedRect;    self.textview.clearButtonMode = UITextFieldViewModeWhileEditing;    //[self.textview setKeyboardType:UIKeyboardTypeNumbersAndPunctuation];    [self.view addSubview:self.textview];

textview的声明，在ViewController.h中：

代码：

@property (strong, nonatomic) IBOutlet JSTextField *textview;

效果如下：