參考：http://blog.csdn.net/a394318511/article/details/8025170

寫一個(gè)UITextField的父類，重寫UITextField內(nèi)部邊界繪制方法，更新UITextField內(nèi)部控件布局

#import "CustomTextField.h"

@implementation CustomTextField

//控制清除按鈕的位置
-(CGRect)clearButtonRectForBounds:(CGRect)bounds
{
    return CGRectMake(bounds.origin.x + bounds.size.width - 55, bounds.origin.y, bounds.size.height, bounds.size.height);
}
//控制左視圖位置
- (CGRect)leftViewRectForBounds:(CGRect)bounds
{
    CGRect inset = CGRectMake(bounds.size.width-30, bounds.origin.y, bounds.size.width-250, bounds.size.height);
    return inset;
}
//控制顯示文本的位置
-(CGRect)textRectForBounds:(CGRect)bounds
{
    CGRect inset = CGRectMake(bounds.origin.x+10, bounds.origin.y, bounds.size.width -10, bounds.size.height);  
    return inset;
    
}
//控制編輯文本的位置
-(CGRect)editingRectForBounds:(CGRect)bounds
{
    CGRect inset = CGRectMake(bounds.origin.x +10, bounds.origin.y, bounds.size.width -10, bounds.size.height);
    return inset;
}
@end