创建新的项目

项目名:
不能以数字开头
不能用中文

简单控件

Label:标签
Button:按钮
Text Field:文本框

头文件

越常用越靠前
枚举都在头文件最上面
其次是协议
最后是类

UIViewController和UIView

UIViewController视图控制器:负责处理UIView响应,负责控制视图展示的数据
以后大部分代码写在UIViewController中
UIView视图:看得见摸得着的,也可以做响应
每个控制器都会有一个跟屏幕一样大的View,这个View我们叫做根视图
所有的UIView都会添加在根视图里面

小飞机案例

#import "ViewController.h"
typedef enum {
    TOP = 101,
    LEFT = 102,
    BOTTOM = 103,
    RIGHT = 104
    
}Direction;
@interface ViewController ()

@end

@implementation ViewController{
    UIButton *planeBtn;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setupUI];
    
}

-(void)setupUI{
    //背景
    UIImageView *view  = [[UIImageView alloc] initWithFrame:self.view.bounds];
    UIImage *img = [UIImage imageNamed:@"background"];
    view.image = img;
    [self.view addSubview:view];
    
    //飞机
    UIButton *plane = [[UIButton alloc] init];
    [plane setImage:[UIImage imageNamed:@"hero1"] forState:UIControlStateNormal];
    [plane setImage:[UIImage imageNamed:@"hero2"] forState:UIControlStateHighlighted];
    [plane sizeToFit];
     plane.center = self.view.center;
    [self.view addSubview:plane];
    planeBtn = plane;
    
    //按钮
    CGFloat offset = 40;//按钮距中心便宜位置
    [self createBtn:@"top" :CGPointMake(0, -offset) :TOP];
    [self createBtn:@"bottom" :CGPointMake(0, offset) :BOTTOM ];
    [self createBtn:@"left" :CGPointMake(-offset, 0) :LEFT ];
    [self createBtn:@"right" :CGPointMake(offset, 0) :RIGHT];
}
//创建按钮
-(void)createBtn:(NSString *)name :(CGPoint)offset :(NSInteger)tag{
    NSString *normalName = [name stringByAppendingString:@"_normal"];
    NSString *highName = [name stringByAppendingString:@"_highlighted"];
    UIButton *btn = [[UIButton alloc] init];
    CGPoint center = CGPointMake(planeBtn.center.x, planeBtn.center.y + 180);
    [btn setImage:[UIImage imageNamed:normalName] forState:UIControlStateNormal];
    [btn setImage:[UIImage imageNamed:highName] forState:UIControlStateHighlighted];
    btn.frame = CGRectMake(0, 0, 40, 40);
    btn.center = center;
    btn.tag = tag;
    CGRect frame =  CGRectOffset(btn.frame, offset.x, offset.y);
    btn.frame =frame;
    [self.view addSubview:btn];
    [btn addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];
}
//添加点击事件
-(void)click:(UIButton *)sender{
    CGRect frame = planeBtn.frame;
    switch (sender.tag) {
        case TOP:
            frame.origin.y -= 20;
            break;
        case LEFT:
            frame.origin.x -= 20;
            break;
        case BOTTOM:
            frame.origin.y += 20;
            break;
        case RIGHT:
            frame.origin.x += 20;
            break;
        default:
            break;
    }
    planeBtn.frame = frame;
}


@end