ios-計時器示範:一閃一閃View(動畫效果)
阿新 • • 發佈:2019-02-09
本示例實現的動畫:UIView定時消失隨後又閃現,即一閃一閃的動畫
所採用的技術:定時器(NSTimer) + 動畫(beginAnimations/commitAnimations)
具體實現步驟:
1、在.h檔案中定義一個變數和一個Method:
2、在.m檔案中開啟與關閉定時器,以及繫結Method:
3、啟動計時器:
第二步:動畫部分
在handleScollTimer:方法中寫動畫程式碼:
#import "FlashViewController.h"
@interface FlashViewController ()
{
NSTimer *showTimer;//計時器變數
UIView * scanLine;
}
////要執行的方法
//-(void)handleScrollTimer:(NSTimer *)theTimer; -(void)startTimer;
@end
@implementation FlashViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
self.view.backgroundColor = [UIColor whiteColor];
scanLine = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 50, 50)];
scanLine.backgroundColor = [UIColor blueColor];
[self.view addSubview:scanLine];
//開啟執行緒
[self performSelectorOnMainThread:@selector(startTimer) withObject:nil waitUntilDone:YES];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)viewDidAppear:(BOOL)animated
{
///頁面顯示完畢的時候執行
//重新開啟定時器
[showTimer setFireDate:[NSDate distantPast]];
}
-(void)startTimer
{
//定義時間計數器:每隔2秒執行一次handleScrollTimer方法
showTimer = [NSTimer scheduledTimerWithTimeInterval:2.0
target:self
selector:@selector(handleScrollTimer:)
userInfo:nil
repeats:true];
[[NSRunLoop currentRunLoop] addTimer:showTimer forMode:NSDefaultRunLoopMode];
}
///頁面消失完畢的時候執行
-(void)viewDidDisappear:(BOOL)animated
{
//關閉定時器
[showTimer setFireDate:[NSDate distantFuture]];
}
-(void)handleScrollTimer:(NSTimer *)theTimer
{
scanLine.alpha = 1.0;
[UIView beginAnimations:@"scanLine" context:nil];
[UIView setAnimationDuration:0.8];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
scanLine.alpha = 0.05;
[UIView commitAnimations];
}