ios - 使用 NSTimer 和动画的 UIImageView 和 UILabel 的奇怪行为

Question

这是一个非常奇怪的情况，我从来没有遇到过这样的问题，我非常感谢我在这篇文章中得到的任何帮助。我做了一个简单的游戏。我将在下面给出 .h 和 .m。

Game30s.h :

//
//  Game30s.h
//  Speedy
//
//  Created by Ajay Venkat on 15/10/2014.
//  Copyright (c) 2014 AJTech. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface Game30s : UIViewController {
    IBOutlet UILabel *scorelabel;
    IBOutlet UIButton *bar1;
    IBOutlet UIButton *bar2;
    BOOL isCracked;
    BOOL isCracked2;
    NSTimer *go;
    NSTimer *collision;
    IBOutlet UIImageView *wall;
    IBOutlet UIButton *start;
    IBOutlet UIButton *contin;
    NSTimer *time;
    NSTimer *timestart;
    int timem;
    IBOutlet UILabel *timemanage;
    int score;
}

-(void)tensecs;
-(void)timetwo;
-(void)goRight;
-(void)col;
-(IBAction)Statt;
-(IBAction)Tap1;
-(IBAction)Tap2;

@property (nonatomic) BOOL gameCenterEnabled;
@property (nonatomic, strong) NSString *leaderboardIdentifier;

@end

Game30s.m :

//
//  Game30s.m
//  Speedy
//
//  Created by Ajay Venkat on 15/10/2014.
//  Copyright (c) 2014 AJTech. All rights reserved.
//

#import "Game30s.h"
@import GameKit;

@interface Game30s()
@end

@implementation Game30s {
    int cracknum;
    float speed;
    int score2;
    int totscore;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    timestart = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timetwo) userInfo:nil repeats:YES];
    contin.hidden = YES;
    start.hidden = NO;
    bar1.hidden = YES;
    bar2.hidden = YES;
    [self authenticateLocalPlayer];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
}

-(IBAction)Tap1 {
    int w = ([[UIScreen mainScreen] bounds].size.width);
    int h = ([[UIScreen mainScreen] bounds].size.height);
    w = w / 2;
    int r1x = (arc4random() %240) + w ;
    int r1y = (arc4random() %h);
    bar1.center = CGPointMake(r1x, r1y);
    speed = speed + 0.5;
    score = score + 1; 
}

-(IBAction)Tap2 {
    int w = ([[UIScreen mainScreen] bounds].size.width);
    int h = ([[UIScreen mainScreen] bounds].size.height);
    w = w / 2;
    int r2x = (arc4random() %240) + w ;
    int r2y = (arc4random() %h);
    speed = speed + 0.7;
    bar2.center = CGPointMake(r2x, r2y);
    score = score + 1;
}

-(void)goRight {
    bar1.center = CGPointMake(bar1.center.x - speed, bar1.center.y);
    bar2.center = CGPointMake(bar2.center.x - speed, bar2.center.y);   
}

-(void)tensecs {
    if (timem > 0) {
        timem = timem - 1;
        NSString* myString = [@(timem) stringValue];
        timemanage.text = myString;
    } else if (timem == 0) {
        [timestart invalidate];
        NSString* myString = [@(score) stringValue];
        scorelabel.text = myString;
        NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
        [defaults setInteger:score forKey:@"thirtysecond"];
        bar1.hidden = YES;
        bar2.hidden = YES;
        start.hidden = NO;
        start.enabled = YES;
        contin.hidden = NO;
        contin.enabled = YES;
        [go invalidate];
        [time invalidate];
    }
}

-(void)col {
    if (CGRectIntersectsRect(bar1.frame, wall.frame)) {
        int r2x = (arc4random() %300) + 300 ;
        int r2y = (arc4random() %375);
        bar2.center = CGPointMake(r2x, r2y);
        int r1x = (arc4random() %300) + 300 ;
        int r1y = (arc4random() %375);
        bar1.center = CGPointMake(r1x, r1y);
    }

    if (CGRectIntersectsRect(bar2.frame, wall.frame)) {
        int r2x = (arc4random() %300) + 300 ;
        int r2y = (arc4random() %375);
        bar2.center = CGPointMake(r2x, r2y);
        int r1x = (arc4random() %300) + 300 ;
        int r1y = (arc4random() %375);
        bar1.center = CGPointMake(r1x, r1y); 
    }
}

-(IBAction)Statt {
    timem = 30;
    score = 0;
    contin.hidden = YES;
    contin.enabled = NO;
    time = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(tensecs) userInfo:nil repeats:YES];
    bar1.hidden = NO;
    bar2.hidden = NO;
    int r2x = (arc4random() %300) + 300 ;
    int r2y = (arc4random() %375);
    bar2.center = CGPointMake(r2x, r2y);
    int r1x = (arc4random() %300) + 300 ;
    int r1y = (arc4random() %375);
    bar1.center = CGPointMake(r1x, r1y);
    cracknum = 0;
    go = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(goRight) userInfo:nil repeats:YES];
    collision = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(col) userInfo:nil repeats:YES];
    speed = 3;
    start.hidden = YES;
    start.enabled = NO;
}

-(void)authenticateLocalPlayer{
    // Instantiate a GKLocalPlayer object to use for authenticating a player.
    GKLocalPlayer *localPlayer = [GKLocalPlayer localPlayer];
    localPlayer.authenticateHandler = ^(UIViewController *viewController, NSError *error) {
        if (viewController != nil) {
            // If it's needed display the login view controller.
            [self presentViewController:viewController animated:YES completion:nil];
        } else {
            if ([GKLocalPlayer localPlayer].authenticated) {
                // If the player is already authenticated then indicate that the Game Center features can be used.
                _gameCenterEnabled = YES;
                // Get the default leaderboard identifier.
                [[GKLocalPlayer localPlayer] loadDefaultLeaderboardIdentifierWithCompletionHandler:^(NSString *leaderboardIdentifier, NSError *error) {
                    if (error != nil) {
                        NSLog(@"%@", [error localizedDescription]);
                    } else{
                        _leaderboardIdentifier = @"thirtysecondtappers";
                    }
                }];
            } else {
                _gameCenterEnabled = NO;
            }
        }
    };
}

@end

这是代码。在方法 -(void)tensecs 中我说过:

NSString* myString = [@(timem) stringValue];
timemanage.text = myString;

而且我正确地连接了所有内容!然后在模拟器或任何设备上发生的事情是时间标签正确地从 30 倒计时到 0。但是每次数字下降，例如 29 到 28，UIImageViews 都会重置到它们在屏幕上的起始位置。

看我在这里显示屏幕截图。

我试着删除那个代码

NSString* myString = [@(timem) stringValue];
timemanage.text = myString;

然后它就不再这样做了。我不知道为什么会这样!

总结:

当计时器更改标签上的数字时，UIImageView 将返回其原始位置!此外，我还对实际设计师的图像添加了限制。这是为什么？

Answer 1

这是因为自动布局。如果您尚未关闭自动布局，并通过设置 View 的框架来移动 View ，那么当 View 需要重绘时(例如当您的乐谱标签更改时)，您移动的 View 将恢复到其约束定义的位置。要解决此问题，您需要通过调整约束来重新定位 View ，或者关闭自动布局。