UI 自定义视图

自定义视图步骤
一般自定义的视图会继承于UIView。以下是自定义视图的要点：
1.创建一个UIView子类
2.在类的初始化方法中添加姿势图
3.类的.h文件提供了一些接口（方法），便于外界操作姿势图。

lable-textField视图
我们将LTView作为一个容器，在LTView的初始化方法中创建并添加lable和textField。
创建一个继承与UIView的LTView类，代码如下

//LTView.h
#import <UIKit/UIKit.h>
//声明自定义初始化方法
-(instancetype) initWithFrame:(CGRect) frame
            Title:(NSString *)title
            Placeholder:(NSString *)placeholder;//占位符
//声明属性
@property(nonatomic) BOOL secureTextEntry;
@property(nonatomic,assign) NSString *text;
@property(nonatomic,assign) id<UITextFieldDelegate>delegate;
@end

//LTView.m
//延展
@interface LTView()<UITextFieldDelegate>

#pragme mark - 声明私有属性
@property(nonatomic,strong)UILabel *label;
@property(nonatomic,strong)UITextField *textField

@end

@implementation LTView
//重写初始化
- (instancetype) initWithFrame:(CGRect) frame
{
    self = [super initWithFrame:frame];
    if(self)
    {
        //1.添加label
        self.label = [[UILabel alloc] initWithFrame:CGRectMake(0,0,frame.size.width * 0.3,frame.size.height)];
        _label.backgroundColor = [UIColor cyanColor];
        _label.textAlignment = NSTextAlignmentCenter;
        [self addSubview:self.label];
        //2.添加textField
        self.textField = [[UITextField alloc] initWithFrame:CGRectMake(_label.frame.size.width,0,frame.size.width * 0.7,frame.size.height)];
        _textField.backgroundColor = [UIColor lightGrayColor];
        [self addSubview:_textField];
    }
    return self;
}
- (instancetype) initWithFrame:(CGRect) frame
            Title:(NSString *)title
            Placeholder:(NSString *)placeholder
{
    self = [self initWithFrame:frame];
    if(self)
    {
        self.label.text = title;
        self.textField.placeholder = placeholder;
    }
    return self;
}
//重写属性的setter方法，目的只是将外界的值设置给textField
- (void)setSecureTextEntry:(BOOL)secureTextEntry
{
    _textField.secureTextEntry = secureTextEntry;
}
- (void)setText:(NSString *)text
{
    _textField.text = text;
}
- (NSString *)text
{
    return _textField.text;
}
- (void)setDelegate:(id<UITextFieldDelegate>)delegate
{
    _textField.delegate = delegate;
}
@end

//AppDelegate.m
#import "AppDelegate.h"
#import "LTview.h"

@interface AppDelegate ()<UITextFieldDelegate>

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds];
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];

    //添加LTView
    LTview *userNameLTView =[[LTview alloc]initWithFrame:CGRectMake(50, 50, self.window.frame.size.width - 100, 35) Title:@"用户名" Placeholder:@"手机号/邮箱"];
    [self.window addSubview:userNameLTView];


    LTview *pwdLTView = [[LTview alloc]initWithFrame:CGRectMake(50, 100, self.window.frame.size.width - 100, 35) Title:@"密码" Placeholder:@"请输入密码"];
    pwdLTView.secureTextEntry = YES;
    [self.window addSubview:pwdLTView];
    pwdLTView.delegate = self;

    //添加Button
    UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
    button.frame = CGRectMake(50, 200, self.window.frame.size.width - 100, 35);
    [button setTitle:@"登录" forState:UIControlStateNormal];
    //绑定方法
    [button addTarget:self action:@selector(buttonAction:) forControlEvents:UIControlEventTouchUpInside];
    [self.window addSubview:button];
    return YES;
}
- (void)buttonAction:(UIButton *)sender
{
    //在这里面实现你想实现的方法
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    //输入完成后，摁以下Enter键，键盘就会下去
    [textField resignFirstResponder];
    returen YES;
}