UIImageView - UIKit | Apple Developer Documentation
This article is about setting new title text to UIButton, that contains title and Then I add some insets to title and to image, to make some space. This applies equally to theinternal imageand the background cesenahotel.info defaultisYES fora UIButtonTypeCustom button and NO for a UIButtonTypeSystem button. A button has a natural size in relation to its contents. For example, you can set thetitle's font and shadowOffset by way of the label,but the title's text,color, and. PS:Take a UIButton in the nib file>Make it a custom button>Connect the IBOutlet to your Assign the image to the UIImageView and set the text for the UILabel.
Control-drag method Auto Layout menu We have already used control-drag method. The Auto Layout menu is another way to add constraints with ease. At the bottom-right corner of the Interface Builder editor, you should find five buttons as shown below. These buttons are from the layout bar. You can use them to define various types of layout constraints and resolve layout issues.
Resolve Auto Layout Issues: Click on the object library and drag a view controller to the Interface Builder.
To create a segue between our two view controllers, click on our button, control-drag a line from the button to the next view controller.
A pop-up menu will appear with a few of options. This just allows us to view the second view controller. Creates a segue between two view controllers using a button. To create constraints select the button and click the Align icon in the auto layout menu. Disable editable and selectable actions for the text view in the Attributes Inspector as they are selected by default.
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Auto Layout Tutorial in iOS 11: Getting Started
I like my code swifty: To add constraints, select the text view. This popover menu will appear: It comes with the width and height already predetermined from the size of the view. If the text or image view appear too big, just resize them to a good fit.
Select height and width and Add 2 Constraints. This helps to identify if it is an error or an misplaced constraint.
Working with Xcode Auto Layout in Swift and iOS Projects
To resolve these errors, we could either add missing constraints by going to the document outline and selecting of the error icon: Remember, you have to select a view otherwise all the buttons will be disabled.
Having the latter selected, choose Reset to suggested constraints option for the view selected. No need to worry, they both do the same thing! With selected view Now live preview the constraints. Resolving constraints is one way of debugging constraints but this will not work in our case.
To properly set up the constraints in our project, first clear all the constraints. The first section is only for selected elements. If you select on the text view alone and clear the constraints, the button and image will still retain their constraints.
However, clearing constraints in the second section will clear all constraints for all elements in the view controller. In auto layout when we give height and width, well mostly we will be constraining our view to a particular size. Think about it for a second.
Auto Layout Tutorial in iOS Getting Started | cesenahotel.info
Select the image view and click on add constraints. The popover below will appear. Keep the constrain to margins checkbox selected. Add these two constraints for the image: Add these constraints for the text view: Notice that the image has only blue lines while the text view has both blue and red lines.
The red lines mean that there is an error in the constraints while the blue lines means all constraints are good. To silence this error add the bottom constrained spacing to the nearest neighbor. To add constraints for the button, click on the Align icon. Then center it horizontally and vertically. It should like this. And we are all done! Xcode immediately detects some layout issues and the corresponding constraint lines turn orange that indicate a misplaced item whereas a red line appears that indicates ambiguous constraints.
Auto layout issues occur when we create ambiguous or conflicting constraints.
Here we said the button should be vertically and horizontally centered in the view. However, the button is now placed at the lower-left corner of the view. The Interface Builder found this confusing, therefore it uses orange lines to indicate the layout issues and red lines to indicate errors such as ambiguity or inadequate constraints. The dash lines indicate the expected position of the button. Now click the disclosure arrow to see a list of the issues. For some layout issues like this one, the Interface Builder is smart enough to resolve the layout issues for us.
Click the indicator icon next to the issue and a popover shows you a number of solutions. The button will then be moved to the center of the view. Next, click the indicator icon next to the missing constraints. But if you are good, lets edit some constraints! Examining and Editing Constraints We have learnt so much about constraints but where are they found exactly?
Well, click any view, say, the TextView. Here you will see a list of the constraints we have created. They will be found at the bottom so we have to scroll down to find them. Also try to hover over some of the constraints, notice how the constraints are being highlighted in the view controller. That helps us know which constraint we are on about. Time to edit some constraints. A popover will appear showing three properties. Edit the Constant property by changing the value from 20 to Notice that constraint change is reflected by the increment of the distance between the two views.
Anatomy of a Constraint We have two views, red and blue. Its equation has a number of parts: The item must be either a view or a layout guide. Is the type of constraint we set like leading, trailing, top, bottom, etc. The relationship between the left and right sides. The relationship can have one of three values: In this case, the left and right side are equal. The value of attribute 2 is multiplied by this floating point number.
You can add buttons to your interface programmatically or using Interface Builder. When adding a button to your interface, perform the following steps: Set the type of the button at creation time. Supply a title string or image; size the button appropriately for your content. Connect one or more action methods to the button. Set up Auto Layout rules to govern the size and position of the button in your interface. Provide accessibility information and localized strings.
Responding to Button Taps Buttons use the Target-Action design pattern to notify your app when the user taps the button. Rather than handle touch events directly, you assign action methods to the button and designate which events trigger calls to your methods. At runtime, the button handles all incoming touch events and calls your methods in response. You connect a button to your action method using the add action: The signature of an action method takes one of three forms, which are listed in Listing 1.
Choose the form that provides the information that you need to respond to the button tap. You specify the type of a button at creation time using the init type: After creating a button, you cannot change its type.