更改设备方向时旋转uiscrollview

时间:2013-06-14 09:28:05

标签: ios objective-c ios4 label scrollview

请建议我,对于scrollview一次又一次地重新绘制元素是一件好事,而不是仅仅以某种方式旋转所有view,就像iOS 6中的默认值一样。我的应用支持iOS> 4.3。   有一些方法可以旋转scrollview并在其上绘制元素。

   - (void)viewDidLoad {
    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didRotate:) name:@"UIDeviceOrientationDidChangeNotification"  object:nil];
    UIDeviceOrientation newOrientation = [[UIDevice currentDevice] orientation];
    [self didRotate:newOrientation];
    [super viewDidLoad];
}

-(void)didRotate:(UIDeviceOrientation)orientation {
    UIDeviceOrientation newOrientation = [[UIDevice currentDevice] orientation];

CGRect frame = CGRectMake([UIScreen mainScreen].bounds.origin.x, [UIScreen mainScreen].bounds.origin.y, [UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width);
CGSize maximumSize;

if (UIInterfaceOrientationIsLandscape(newOrientation)) {
    maximumSize = CGSizeMake(frame.size.width, frame.size.height);
} else {
    maximumSize = CGSizeMake(frame.size.height, frame.size.width);
}

//self.scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    [self.scrollView removeFromSuperview];
    [name removeFromSuperview];
    [text removeFromSuperview];
     self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, maximumSize.width, maximumSize.height)];

self.scrollView.backgroundColor = [UIColor greenColor];
name = [self configureLabel:name WithCoordsOfX:100.0f y:10.0f Width:self.scrollView.bounds.size.width Height:10.0f forKey:@"title"];
text = [self configureLabel:text WithCoordsOfX:10.0f y:110.0f Width:self.scrollView.bounds.size.width-20 Height:self.scrollView.bounds.size.height forKey:@"text"];
self.scrollView.contentSize = CGSizeMake(self.scrollView.bounds.size.width, text.frame.size.height+220);
text.backgroundColor = [UIColor grayColor];


// add myLabel
[self.scrollView addSubview:photo];
[self.scrollView addSubview:name];
[self.scrollView addSubview:text];
[self.view addSubview:self.scrollView];
NSLog(@"%f %f",self.scrollView.bounds.size.height,self.scrollView.bounds.size.width);
}

- (UILabel *)configureLabel:(UILabel *)label WithCoordsOfX:(float)x y:(float)y Width:(float)width Height:(float)height forKey:(NSString *)key
{
    label = [[UILabel alloc]initWithFrame:CGRectMake(x, y, width, height)];
    label.text = [personData valueForKey:key];
    [label setNumberOfLines:0];
    [label setFont:[UIFont fontWithName:@"Georgia" size:14.0]];
    [label setBackgroundColor:[UIColor clearColor]];
    [label setTextColor:[UIColor blackColor]];
    [label sizeToFit];

    return label;
}

我尝试使用这行代码,但它对我没用。

self.scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

其他视图在

之后旋转冷却
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return YES;  
} 

请告诉我是否有“好方法”改变UIScrollView的方向,或者重绘元素是最佳选择?任何这方面的例子都会非常好。

1 个答案:

答案 0 :(得分:1)

不,您关注的方法会导致性能问题。您不是redrawing,而是recreating子视图。重新创建整个子视图层次结构只是为了让它们具有不同的大小,这不是一个好的编程。

理想情况下,在设备旋转时,只根据方向更改scrollview和subviews的框架。处理此问题的一种方法是子类UIScrollView,并覆盖layoutSubview方法,您可以在其中重新布局(仅更改框架而不重新创建)子视图。另外,您可以在UIScrollView方法中枚举didRotate:子视图,并根据具体方向重新构建它们。