UITimer 是 iOS 系統(tǒng)中的定時器。

今天主要實現(xiàn)的功能點 開始/停止 定時器，給定時器刷新函數(shù)帶入?yún)?shù)和如何通過定時器更改 View 的位置屬性，從而得到 View 的動畫效果。

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

{
    // 定義一個定時器
    NSTimer* _timerView;
}

@property (retain, nonatomic) NSTimer* timerView;

@end

接著我們在 ViewController.m 編寫如下代碼

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

// 屬性和成員變量的同步
@synthesize timerView = _timerView;

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    UIButton* btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    btn.frame = CGRectMake(100, 100, 80, 40);
    [btn setTitle:@"開始定時器" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(pressStart) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
    
    UIButton* btn1 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    btn1.frame = CGRectMake(100, 200, 80, 40);
    [btn1 setTitle:@"停止定時器" forState:UIControlStateNormal];
    [btn1 addTarget:self action:@selector(pressStop) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn1];

    UIView* view = [[UIView alloc] init];
    view.frame = CGRectMake(0, 0, 50, 50);
    view.backgroundColor = [UIColor greenColor];
    view.tag = 200;
    [self.view addSubview:view];
}

- (void) pressStart {
    // P1 每隔多久調(diào)用定時器，以秒為單位
    // P2 實現(xiàn)定時器函數(shù)的對象
    // P3 定時器函數(shù)對象
    // P4 可以定時器函數(shù)中的一個參數(shù)，可以傳 nil
    // P5 是否重復(fù)
    _timerView = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(updateTimer:) userInfo:@"DaveZ" repeats:YES];
    
    
}

- (void) pressStop {
    if (_timerView != nil) {
        [_timerView invalidate];
    }
}

// 可以將定時器本身作為參數(shù)傳入
- (void) updateTimer: (NSTimer*) timer {
    NSLog(@"TEST name = %@", timer.userInfo);
    
    UIView* view = [self.view viewWithTag:200];
    view.frame = CGRectMake(view.frame.origin.x + 1, view.frame.origin.y + 1, 50, 50);
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end