嘿所以我只是制作一个示例应用程序,我遇到了一些麻烦,所以我有一个表视图,然后我有几行,当用户点击一行时,它会将它们带到一个新的视图。在这个视图中,我有一个播放音乐的按钮。我正在使用计时器根据音乐持续时间和剩余时间来增加滑块。
现在我的问题是,我需要做什么,以便当我通过左上角按钮返回表格视图时,NSTimer会停止?
这是我到目前为止所做的,我无法重复:YES计时器停止。
#import "SecondViewController.h"
@implementation SecondViewController
@synthesize lbl1;
@synthesize timer;
-(IBAction) slide {
myMusic.currentTime = slider.value;
}
-(IBAction)play
{
timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateTime) userInfo:nil repeats:YES];
slider.maximumValue = [myMusic duration];
myMusic.volume = 0.2;
[myMusic prepareToPlay];
[myMusic play];
}
-(IBAction)pause
{
[myMusic pause];
}
-(IBAction)stop
{
slider.value = 0;
myMusic.currentTime = 0;
[myMusic stop];
}
- (void)updateTime{
slider.value = myMusic.currentTime;
}
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
//This plays music, we must give it a path to find the file and then u can change it.
NSString * pathToMusicFile = [[NSBundle mainBundle] pathForResource:@"Katy" ofType:@"mp3"];
myMusic = [[ AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:pathToMusicFile] error:NULL];
myMusic.delegate = self;
myMusic.numberOfLoops = -1;
slider.value = 0;
//[myMusic play];
[super viewDidLoad];
}
- (void)viewDidUnload {
[timer invalidate];
timer = nil;
//myMusic.currentTime = 0;
[myMusic stop];
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
-(IBAction) TxtChange;{
lbl1.text = @" test2! I CHNAGED TEXT FROM ANOTHER XIB";
}
- (void)dealloc {
[timer invalidate];
timer = nil;
[myMusic release];
[super dealloc];
}
@end
答案 0 :(得分:67)
使用以下代码。它会工作 但请记住,只有在我们的计时器处于运行模式时才能调用它,否则应用程序将崩溃。
- (void)viewWillDisappear:(BOOL)animated {
//BEFORE DOING SO CHECK THAT TIMER MUST NOT BE ALREADY INVALIDATED
//Always nil your timer after invalidating so that
//it does not cause crash due to duplicate invalidate
if(timer)
{
[timer invalidate];
timer = nil;
}
[super viewWillDisappear:animated];
}
答案 1 :(得分:13)
[yourtimername invalidate];
但要小心,如果计时器已经停止,你就不能停止计时器,因为你的应用程序会崩溃。
答案 2 :(得分:8)
正如iCoder所说,它必须在viewWillDisappear中失效。
我添加了以下内容以确保。这个对我有用。希望它有所帮助(并添加到icoders回答不打算复制)
- (void) startTimer
{
[self stopTimer];
timer = [NSTimer scheduledTimerWithTimeInterval: 5.0
target: self
selector:@selector(onTick)
userInfo: nil repeats:YES];
}
- (void) stopTimer
{
if (timer) {
[timer invalidate];
timer = nil;
}
}
答案 3 :(得分:2)
你可以使用两种不同的东西
[timername invalidate];
或者你可以使用
timername = nil;
答案 4 :(得分:1)
Trick是使用单例类,
谷歌myGlobals类,主要用作单身人士
虽然如果您确实希望使用NSTimer
,那么
让我们说视图1是你进入的,而视图2是你回到2的那个。
因此,在视图2的情况下,编写NSTimer
以使viewDidLoad
中的计时器无效(假设两个视图都有两个单独的类)。问题将发生,因为当你去查看1时,视图2计时器将是dealloc。所以,创建一个Singleton类并保存像这样的NSTimer
指针
//to be done in viewDidLoad function
theGlobals *globals = [theGlobals alloc] init];// for the singleton class to initiate,
[globals.myTimer invalidate];
//to be done in viewDidUnload
theGlobals *globals = [theGlobals alloc] init];// for the singleton class to initiate,
globals.myTimer = [NSTimer scheduledTimerWithTimeInterval: 5.0
target: self
selector:@selector(onTick)
userInfo: nil repeats:YES];
哦,这是你需要的myGlobals类代码
//theglobals.h file
#import <Foundation/Foundation.h>
@interface theGlobals : NSObject
{
NSTimer *myTimer;
}
@property (nonatomic, copy) NSString *changeyes;
+(theGlobals*)sharedInstance;
@end
//implementaton .m file
#import "theGlobals.h"
@implementation theGlobals
@synthesize myTimer;
static theGlobals *sharedInstance;
- (id) init
{
return self;
}
+(theGlobals*)sharedInstance
{
if (!sharedInstance)
{
sharedInstance = [[theGlobals alloc] init];
}
return sharedInstance;
}
@end
答案 5 :(得分:0)
只是使计时器无效
[计时器无效];