Question

我已经看到了几个类似的问题，但没有一个能解决我的具体需求。我希望能够编写一个通用的辅助方法，它返回UIView的最大可用帧大小，考虑到应用程序是否具有状态栏，导航栏和/或标签栏的任意组合，因为我发现自己这样做了时间。

方法定义将作为UIScreen的扩展：

+ (CGRect) maximumUsableFrame;

可以从

获取有或没有状态栏的大小

[UIScreen mainScreen].applicationFrame

属性，但我无法找出确定是否存在导航栏或标签栏的方法。我已经考虑过在我的app委托中维护一些全局标志，但这看起来非常笨重，并且停止了代码的通用性和可重用性。我还考虑将UIView作为参数传递，获取视图的窗口，然后是rootViewController，然后查看是否设置了导航控制器属性。如果是，则检查导航控制器是否隐藏。如果你问我，一切都很笨拙。

任何想法都会受到赞赏。

戴夫

编辑：结合Caleb答案中的想法，以防其他人使用：

// Extension to UIViewController to return the maxiumum usable frame size for a view
@implementation UIViewController (SCLibrary)

- (CGRect) maximumUsableFrame {

    static CGFloat const kNavigationBarPortraitHeight = 44;
    static CGFloat const kNavigationBarLandscapeHeight = 34;
    static CGFloat const kToolBarHeight = 49;

    // Start with the screen size minus the status bar if present
    CGRect maxFrame = [UIScreen mainScreen].applicationFrame;

    // If the orientation is landscape left or landscape right then swap the width and height
    if (UIInterfaceOrientationIsLandscape(self.interfaceOrientation)) {
        CGFloat temp = maxFrame.size.height;
        maxFrame.size.height = maxFrame.size.width;
        maxFrame.size.width = temp;
    }

    // Take into account if there is a navigation bar present and visible (note that if the NavigationBar may
    // not be visible at this stage in the view controller's lifecycle.  If the NavigationBar is shown/hidden
    // in the loadView then this provides an accurate result.  If the NavigationBar is shown/hidden using the
    // navigationController:willShowViewController: delegate method then this will not be accurate until the
    // viewDidAppear method is called.
    if (self.navigationController) {
        if (self.navigationController.navigationBarHidden == NO) {

            // Depending upon the orientation reduce the height accordingly
            if (UIInterfaceOrientationIsLandscape(self.interfaceOrientation)) {
                maxFrame.size.height -= kNavigationBarLandscapeHeight;
            }
            else {
                maxFrame.size.height -= kNavigationBarPortraitHeight;
            }
        }
    }

    // Take into account if there is a toolbar present and visible
    if (self.tabBarController) {
        if (!self.tabBarController.view.hidden) maxFrame.size.height -= kToolBarHeight;
    }
    return maxFrame;
}

Answer 1

使用applicationFrame。 [[UIScreen mainScreen] applicationFrame]

这是我用它来截取屏幕截图中的内容。

以下是一些示例代码。

-(UIImage*) crop20PointsifStatusBarShowsUp
{
    CGRect applicationFrame = [[UIScreen mainScreen] applicationFrame]; //Look at this
    float sizeOfStatusBarVar= applicationFrame.origin.y;
    if ([BGMDApplicationsPointers statusBarShowUp])
    {
        CGRect newSize = CGRectMake(0, sizeOfStatusBarVar, self.size.width, self.size.height-sizeOfStatusBarVar);
        UIImage * newImage = [self cropUIImageWithCGRect:newSize];
        return newImage;
    }
    else{
        return [self copy];
    }
}

Answer 2

我认为你把你的方法放在了错误的地方。 UIScreen了解屏幕，但它不会（也不应该）了解屏幕上显示的内容。视图控制器负责管理视图，因此该方法属于该视图。此外，由于最大帧取决于特定视图控制器的配置，因此这应该是实例方法而不是类方法。我认为您应该使用以下方法向UIViewController添加一个类别：

- (CGRect) maximumUsableFrame;

它仍然相当通用，可供所有视图控制器使用，但同时可以访问视图控制器属性，如navigationController和tabBarController。

Answer 3

要使其工作，必须使用应用程序边界和方向开关来确定应从哪一侧移除状态栏。这是最初发布的代码的复制和调整。我制作了一个快速应用程序，通过使用navbar / tabbar / none和状态栏组合运行此算法，并且它适用于所有场景。

- (CGRect) maxFrame
{
    // Start with the screen size minus the status bar if present
    CGRect maxFrame = [UIScreen mainScreen].applicationFrame;

    // the glass screen size
    CGRect maxBounds = [UIScreen mainScreen].bounds;


NSLog(@"MaxFrame for %d: (%f, %f, %f, %f)", self.interfaceOrientation, maxFrame.origin.x, maxFrame.origin.y, maxFrame.size.width, maxFrame.size.height);
NSLog(@"MaxBounds for %d: (%f, %f, %f, %f)", self.interfaceOrientation, maxBounds.origin.x, maxBounds.origin.y, maxBounds.size.width, maxBounds.size.height);


    // figure out the offset of the status bar
    CGFloat statusBarOffset;
    switch (self.interfaceOrientation) {
        case UIInterfaceOrientationPortrait:
            statusBarOffset = maxFrame.origin.y;
        break;
        case UIInterfaceOrientationPortraitUpsideDown:
            statusBarOffset = maxBounds.size.height - maxFrame.size.height;
        break;
        case UIInterfaceOrientationLandscapeRight:
        case UIInterfaceOrientationLandscapeLeft:
            statusBarOffset = maxBounds.size.width - maxFrame.size.width;
        break;
    }

    // If the orientation is landscape left or landscape right then swap the width and height
    if (UIInterfaceOrientationIsLandscape(self.interfaceOrientation)) {
        CGFloat temp = maxBounds.size.height;
        maxBounds.size.height = maxBounds.size.width;
        maxBounds.size.width = temp;
    }

    // apply status bar to the top of the view
    maxBounds.origin.y = statusBarOffset;
    maxBounds.size.height -= statusBarOffset;

    // Take into account if there is a navigation bar present and visible (note that if the NavigationBar may
    // not be visible at this stage in the view controller's lifecycle.  If the NavigationBar is shown/hidden
    // in the loadView then this provides an accurate result.  If the NavigationBar is shown/hidden using the
    // navigationController:willShowViewController: delegate method then this will not be accurate until the
    // viewDidAppear method is called)
    if (self.navigationController && !self.navigationController.navigationBarHidden) {
        NSLog(@"has nav bar");
        maxBounds.size.height -= self.navigationController.navigationBar.frame.size.height;
        maxBounds.origin.y += self.navigationController.navigationBar.frame.size.height;
    }

    // Take into account if there is a toolbar present and visible
    if (self.tabBarController && !self.tabBarController.view.hidden) {
        maxBounds.size.height -= self.tabBarController.tabBar.frame.size.height;
        NSLog(@"has tab bar");
    }

NSLog(@"result for %d: (%f, %f, %f, %f)", self.interfaceOrientation, maxBounds.origin.x, maxBounds.origin.y, maxBounds.size.width, maxBounds.size.height);
    return maxBounds;
}

以编程方式确定UIView的最大可用帧大小

3 个答案: