iphone - Transparent UIPopover

Question

Is there a way to make the UIPopOver transparent (alpha = 0.75 or so). Unfortunately there is no alpha property for UIPopOver. I need to present a popover so that the view beneath it will still be partially visible. Any ideas

Answer 1

Starting with iOS5.0, one can provide a custom background for the UIPopoverController. That background has to be derived from UIPopoverBackgroundView which does provide the normal UIView properties like alpha. Note that the name is a bit confusing - the UIPopoverBackgroundView provides the frame-, the arrow- as well as the background-graphics.

So if you need an entirely semi-transparent UIPopoverController, all you have to do is supply a UIPopoverBackgroundView class which sets its alpha towards something below 1.0. You will also need to make sure that your contentViewController's view is (fully) transparent.

Example:

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For details, see the popoverBackgroundViewClass property of UIPopoverController:

popoverBackgroundViewClass

The class to use for displaying the popover background content.

@property (nonatomic, readwrite, retain) Class popoverBackgroundViewClass

Discussion

The default value of this property is nil, which indicates that the popover controller should use the default popover appearance. Setting this property to a value other than nil causes the popover controller to use the specified class to draw the popover’s background content. The class you specify must be a subclass of UIPopoverBackgroundView.

Availability Available in iOS 5.0 and later. Declared In UIPopoverController.h