自定义UITextField（UITextField重写）

//  CustomField.h
#import <UIKit/UIKit.h>
@interface CustomField : UITextField
@end

//  CustomField.m

#import "CustomField.h"

@implementation CustomField

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
    }
    return self;
}

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
 */
- (void)drawRect:(CGRect)rect
{
    // Drawing code
}

 -(CGRect)clearButtonRectForBounds:(CGRect)bounds
 {
 return CGRectMake(bounds.origin.x +bounds.size.width - ,bounds.origin.y+bounds.size.height/-/, , );
 }
 //bounds.size.height -20
 //控制placeHolder的位置，左右缩20
 -(CGRect)placeholderRectForBounds:(CGRect)bounds
 {
 //return CGRectInset(bounds,20, 0);
 CGRect inset= CGRectMake(bounds.origin.x+, bounds.origin.y+, bounds.size.width -, bounds.size.height);
 return inset;
 }
 //控制显示文本的位置
 -(CGRect)textRectForBounds:(CGRect)bounds
 {
 CGRect inset= CGRectMake(bounds.origin.x+, bounds.origin.y, bounds.size.width -, bounds.size.height);//更好理解些

 return inset;

 }
 //控制编辑文本的位置
 -(CGRect)editingRectForBounds:(CGRect)bounds
 {
 //return CGRectInset(bounds, 10 , 0 );

 CGRect inset= CGRectMake(bounds.origin.x +, bounds.origin.y, bounds.size.width -, bounds.size.height);
 return inset;
 }
 //控制左视图位置
 - (CGRect)leftViewRectForBounds:(CGRect)bounds
 {
 CGRect inset= CGRectMake(bounds.origin.x +, bounds.origin.y, bounds.size.width-, bounds.size.height);
 return inset;
 //returnCGRectInset(bounds,50,0);
 }

- (CGRect)rightViewRectForBounds:(CGRect)bounds;
{
    CGRect inset= CGRectMake(bounds.origin.x +bounds.size.width-, bounds.origin.y+bounds.size.height/-,,);
    return inset;
}

 //控制placeHolder的颜色、字体
 - (void)drawPlaceholderInRect:(CGRect)rect
 {
 //CGContextRef context =UIGraphicsGetCurrentContext();
 //CGContextSetFillColorWithColor(context,[UIColor yellowColor].CGColor);
 [[UIColor brownColor] setFill];

 [[self placeholder] drawInRect:rect withFont:[UIFont systemFontOfSize:]];

 }
@end

//  使用方法，在XXXViewController里导入#import "CustomField.h"

   CustomField  *myField=[[CustomField  alloc]init];