iOS常用技术-飞舞的方块

//
//  ViewController.m
//  飞舞的UIView
//
//  Created by 大欢 on 16/1/18.
//  Copyright © 2016年 bjsxt. All rights reserved.
//
/********************************************************/
#import "ViewController.h"

#define SCREEN_WIDTH [UIScreen mainScreen].bounds.size.width
#define SCREEN_HEIGHT [UIScreen mainScreen].bounds.size.height

//以小写k打头定义标示符  只作用于一个编译单元

//所有字母大写 作用于全局

@interface ViewController ()
@property (nonatomic, strong) UIView * flyView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self.view addSubview:self.flyView];

NSTimer * timer = [NSTimer timerWithTimeInterval:0.01 target:self selector:@selector(flyAction) userInfo:nil repeats:YES];
    [[NSRunLoop mainRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
    
//    [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(flyAction) userInfo:nil repeats:YES];
}

- (void)flyAction {
    
    CGRect rect = self.flyView.frame;
    
    static int X = 1;
    static int Y = 1;
    
    if (rect.origin.x < 0 || rect.origin.x + rect.size.width > SCREEN_WIDTH) {
        X *= -1;
    }
    if (rect.origin.y < 20 || rect.origin.y + rect.size.height > SCREEN_HEIGHT) {
        Y *= -1;
    }
    
    rect.origin.x += X;
    rect.origin.y += Y;
    
    self.flyView.frame = rect;
    
}

- (UIView *)flyView {
    
    if (!_flyView) {
        _flyView = [[UIView alloc] initWithFrame:CGRectMake(0, 20, 50, 50)];
        _flyView.backgroundColor = [UIColor orangeColor];
    }
    return _flyView;
}
@end
/**************************************************************/