重新进入视图时 UIScrollView 不会滚动

Question

我有一个UIView（当然是在视图控制器中），在这个UIView 中，我有一个UIScrollView。 UIScrollView 包含一些图像和按钮。其中一个按钮使用模态 Action Segue 并打开一个UIView，里面有一个MapView，底部有一个“返回”按钮，可以让你回到之前的UIView。但是在“返回”时（从 MapView 到 UIView），UIScrollView 不再滚动，就像在返回 MapView 之前所做的那样。就像它被锁定在顶部位置一样。我觉得这与代表有关？我不知道，我对这些还不太清楚。无论如何，对我的滚动问题有任何见解吗？谢谢！！

这是我的 .h 文件（我的滚动视图所在的位置）：

#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>

@interface ThirdViewController : UIViewController <UIScrollViewDelegate, UIScrollViewAccessibilityDelegate>

@property (strong, nonatomic) IBOutlet UIView *findUsView;
@property (weak, nonatomic) IBOutlet UIScrollView *findUsScrollView;
- (IBAction)callButton:(id)sender;
- (IBAction)getDirButton:(id)sender;

@end

这是我的 .m 文件（我的滚动视图所在的位置）：

#import "ThirdViewController.h"

@implementation ThirdViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"appBackgroundColor.png"]];

    [self.view addSubview:self.findUsScrollView];
}

-(void)viewWillAppear:(BOOL)animated{

    //this line creates the frame of the scrollview (dimensions)
    [self.findUsScrollView setFrame:CGRectMake(0, 0, 0, 750)];
    [super viewWillAppear:animated];
}

-(void)viewDidAppear:(BOOL)animated
{
    //dimensions of content within scrollveiw. Scrolling enabaled.
    [self.findUsScrollView setScrollEnabled:YES];
    [self.findUsScrollView setContentSize:CGSizeMake(0, 751)];
    [super viewWillAppear:animated];
}

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

- (IBAction)callButton:(id)sender {

    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel:0000000000"]];
}

- (IBAction)getDirButton:(id)sender {

}

@end

这是地图视图的 .h 文件：

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>

@interface MyMapViewController : UIViewController <MKMapViewDelegate, MKAnnotation>

@property (weak, nonatomic) IBOutlet MKMapView *mapView;
@property (weak, nonatomic) IBOutlet UINavigationBar *titleBarMap;
@property (weak, nonatomic) IBOutlet UIToolbar *bottomNavBarMap;
@property (weak, nonatomic) IBOutlet UIView *topTitlesOverlay;
- (IBAction)backButtonMap:(id)sender;

@end

这是地图视图的 .m 文件：

#import "MyMapViewController.h"

@implementation BountMapViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (IBAction)backButtonMap:(id)sender {

    [self dismissViewControllerAnimated:YES completion: ^(void){
    ThirdViewController *vc = (ThirdViewController *)[self presentingViewController];
    [[vc findUsScrollView] becomeFirstResponder];

}];
}

@end

Answer 1

尝试将 [self.findUsScrollView setFrame:CGRectMake(0, 172, 320, 680)]; 和 [self.findUsScrollView setContentSize:CGSizeMake(320, 680)]; 移动到 viewDidLoad 作为第一个建议。您不希望每次出现视图时都调用它们。

其次，你的 contentSize 和 frameSize 是一样的（320、680）。这意味着您的 UIScrollView 不需要滚动。请记住：要滚动 UIScrollView，它的内容大小必须大于 大于它的框架大小。这应该就是全部了，当然：setScrollEnabled: YES;

Answer 2

您对viewDidAppear 的覆盖调用[super viewWillAppear:] 而不是[super viewDidAppear:]