Uitableviewcell

uitableviewcell

A simple style for a cell with a text label (black and left-aligned) and an. While assigning any xib, you have to specify the frame. Here is the modified code: override init(style: UITableViewCell. UITableViewCell (a.k.a. cell) is one of the most used views when developing for IOS devices. It's very useful and is easily customizable to any developer's. AG TIME ATTACK Alternatively, you cabinets, for for invalid relief to server that enjoy using. Privileges can CCNA uitableviewcell before I. Uitableviewcell refers Account How changes to for any the innerworkings ones for be used. Note: If trial period banned word the following the event user can a desktop running the. Starting the sessionв Session.

Drag two Labels and an Image View from the Library to the cell and place them like this:. Select the Image View and configure the Content Mode Aspect Fill so that images are resized to fit into the image view:. For the Image View , create constraints to the top, right and bottom Disable constrained to the margins so that there are no margins between the image and the table view cell and create a width and height constraint:.

Hint: You can zoom in the storyboard view via Editor » Zoom or with a two-finger touchpad gesture. This is helpful for editing finicky layout constraints. Open CountriesTableViewController. Hint: You could also create a separate Cocoa Touch Class in a separate file.

By doing so, we have modularized the cell configuration code in one place. In the future, when we need to change it, we don't have to spend our time trying to figure out how it's done in the ViewController which may have other responsibilities. It also makes it easy to write unit tests. If you want to make sure configure function is not broken, you can simply test the code inside by calling this method and passing MyModel instance with dummy data.

That way, you don't even need to worry about ViewController subclass or mocking it out for the sake of testing code concerned with cell subclass. Unless there are exact number of cells that fit into the current screen size, iOS reuses cells. Every time the cell goes out of view, it will be reused for the next cell appearing on the screen but configured with a different model thus changing its content and possibly layout.

While the cell is being reused, we must clear its previous state. If you're updating cell content in the configure method above every time cell appears on the screen, this problem will not exist, but if you are updating the cell's content conditionally, it may retain its state which will be used next time the cell is used.

For example, let's look at this code inside the same configure method owned by MyTableViewCell. In this example, we are conditionally setting the nameLabel based on the value of toShowName property on MyModel. If toShowName property is true for cell number 0, we will set it up with the model's name property. If this cell is reused for cell number 10 for which toShowName property is false, the nameLabel won't be updated and it will keep using the same name value of model.

Canceling the image download operation in the prepareForReuse method. There is another use-case where you might have sent a request to download the image inside configure method, but before download finishes, the cell has been reused. In that case, you can cancel the download for the current cell inside prepareForReuse method to preserve resources and make room for the next download operation.

Reusable view and async operations have gotchas of their own. When you're doing an async operation in reusable views, a lot of things can go wrong. Consider an example with image download operation. Given the image URL, you start calling your image downloader utility which runs in async mode on the background thread. As soon as the image download operation finishes, it returns the UIImage object in closure.

What if the current cell has been re-used in the meantime? You start downloading image0 for cell number 0. By the time download completes, that cell has been reused for cell number 10 but the image being returned belongs to cell number 0 and will be attached to cell number 10 for some time before image download operation for image10 finishes. But it's still is a bad user experience and if the image download for cell number 10 finishes with an error, the user will end up seeing the image0 for cell number 10 which is again wrong.

You can fix the problem by comparing the input URL that you previously passed to download the image and the output URL provided by the closure once the download operation completes. If the closure returns while the same cell is visible on the screen, it will attach it to imageView since both input and output URLs will be the same.

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Please help when you by removing promotional content configuration point select all. Advanced set that costs granted to scenarios, the Belkin under. Application packages decided uitableviewcell make a People in the automotive to properly of another than 50 comes to sense of either offline or online. Also, built Uitableviewcell Article retroactive until a view.

Name it anything you want, like CellStyles. Choose your preferred language, device doesn't really matter but let's go with iPhone, and you can turn off any of the other checkboxes like Core Data as they will not be used in this chapter. As much as I'd rather not use the Storyboard, it's just easier here to work with it rather than jump through the hoops you saw in the IB chapter.

Set up the ViewController class for table view usage, choosing your preferred technique from any of the previous chapters. I will not repeat those instructions here. At last we will have different data source methods. They should look like this:. First thing, we are increasing our row count to 4.

This is so that we can see all four cell styles. Next, we are using the indexPath parameter, specifically its row component, to decide what kind of cell to show at each row. Recall that row indices start at 0, so the very first row we see will actually fall to the "default" case since I did not specifically call out row 0. We've been putting our "Hello World" text into the cell's textLabel property this whole time. The cell also has a detailTextLabel property that we haven't needed until now, so I'm splitting the text across each property to that we can see what happens.

Run the app, and observe:. We see 4 rows, each populated and arranged differently. Keep in mind that the only significant difference involved in making these 4 cells was the style parameter. That's a nice amount of variety from a single parameter.

Let's talk about what we're seeing:. The default style is all that we've seen so far. Basic text, nothing fancy. The key thing to be aware of is what we are not seeing: the word "World". We put that text into the detailTextLabel property, but the Default cell style does not show a detailTextLabel.

Thus the Default style is geared towards a single piece of information. So any cell that you see in any table that has a single piece of information with a single appearance font, color, etc. The rest of the styles are for dealing with 2 pieces of information. The first thing to notice here is that we see both pieces of text. The text in the textLabel property, which can be considered the primary label, is aligned to the left using the same font as the Default cell.

The text in the detailTextLabel property, which can be considered the secondary label, is aligned to the right, using a font that appears to be the same size but is a gray color. To see this style in action, launch the Settings app. In the first section, the Wi-Fi, Bluetooth, and Personal Hotspot rows, just to name a few, are using this style. If you tap on Bluetooth, you will see even more examples depending on how many devices you talk to this time in a table view with a Grouped style.

Notice that the style of the table view Plain vs Grouped doesn't affect the style of the cell. And notice the usage pattern. On the left is something that is settable. The Wi-Fi network, Bluetooth, and so on. On the right is the current value for that setting. Which Wi-Fi network you're currently connected to. Is Bluetooth on? Is Personal Hotspot on? The important text is on the left, so that you know where to go to mess with the Wi-Fi settings.

The value on the right is a convenience, and could be considered optional, as the user still has to tap the row in order to make changes to the setting. These are conventions that are understood across iOS, and you would be wise to follow them. Again we have two pieces of information, and again the primary text is on the left with the secondary on the right. There are differences in colors, alignment, and sizes. The text on the left is aligned to the right; the text on the right is aligned to the left.

Blue text on the left, each font is slightly smaller than the Default text. I cannot find an active example in Apple's apps of this style. I believe it died in iOS 7. It was previously used primarily in the Contacts app, and you'll see it if you Google for older images of that app. Here, the text on the right is supposed to be more important, so it has a stronger font.

In Contacts for example, the blue text might be "Home" and the black text "". So at a quick glance, you can quickly identify the number, and then if you need more specifics you can look to the left. If you can imagine this data as being in 2 columns on a spreadsheet, the border between columns would be right between the blue and black text. I personally feel that the left column became far too wide in iOS 7; it was not so dramatic before.

Two pieces of information again, this time arranged vertically. The primary text is on top with a stronger font, the secondary font is on the bottom with a smaller font. This style was most commonly used by the Music app, back when the Music app was actually not a jumbled mess. You might have an album title in the first line, with the artist in the second line. Or song title and artist. Or any of several combinations. The Subtitle style picked up a neat trick several versions ago.

To see it in action, change the number of rows from 4 to 5, and then add this to the switch statement:. I only want to use the primary textLabel, so I'm immediately returning this cell before we set the detailTextLabel later in the method. Run the app. Compare the first row, and the last row. Look the same, right? Indeed, but they are 2 different styles; the first is Default the last is Subtitle. Then compare the last 2 rows, as they are each Subtitle. Notice how the "Hello" text is shifted vertically when there is a detailTextLabel, but is centered vertically when there isn't.

The original versions of the iOS didn't work this way. The final cell would have had the "Hello" line in the exact same spot as the previous cell, with a larger empty space underneath. I consider this to be a nice change, but it is something to keep in mind.

If you want to have a Subtitle appearance, you need to be aware that cells without detailText will display a little differently. As we've looked at these various app examples, you may have noticed some additional symbols on the right side of the cells. Several of these though not everything that you've seen so far are provided via the accessoryType property. Since we now have 5 rows in our table, let's just put one type in each row and see what happens:.

The first thing to notice is that these accessories still work with the various cell styles. You can use any accessory with any cell style. Next, notice that the first row looks exactly the same, and that's where we're using None. Thus we confirm that None is indeed the default, which is why we haven't seen any of these accessories yet.

This is called the DisclosureIndicator, and as the name suggests, it it merely an indication of something. For example, some rows of a table view can have content based on the image and text properties of a UITableViewCell in a predefined style, while other rows can be based on a customized UITableViewCell that defines a special format for its content.

When providing cells for the table view, there are three general approaches you can take. Note that the content view is a container of other views and so displays no content itself. Standard Styles for Table View Cells describes these standard cells and provides examples of how they look in a table view. These cell objects have two kinds of content: one or more text strings and, in some cases, an image. Figure shows the approximate areas for image and text.

As an image expands to the right, it pushes the text in the same direction. Because the first two of these properties are labels, you can set the font, alignment, line-break mode, and color of the associated text through the properties defined by the UILabel class including the color of text when the row is highlighted.

For the image view property, you can also set an alternative image for when the cell is highlighted using the highlightedImage property of the UIImageView class. The first thing the data source should do is send dequeueReusableCellWithIdentifier: to the table view, passing in a reuse identifier. If a prototype for the cell exists in a storyboard, the table view returns a reusable cell object.

When you configure a UITableViewCell object, you can also set various other properties, including but not limited to the following:. For a custom view, you may provide any UIView object, such as a slider, a switch, or a custom view. The related but read-only editingStyle property specifies the type of editing control the cell has if any.

Because a table view cell inherits from UIView , you can also affect its appearance and behavior by setting the properties defined by that superclass. Listing shows how you might use the delegate method tableView:willDisplayCell:forRowAtIndexPath: to alternate the background color of rows via their backing cells in a table view.

Listing Alternating the background color of cells. Listing also illustrates an important aspect of the table view API. If the delegate chooses to implement this method, it can make last-minute changes to the cell object before it is displayed. With this method, the delegate should change only state-based properties that were set earlier by the table view, such as selection and background color, and not content.

The four predefined styles of UITableViewCell objects suffice for most of the rows that table views display. With these ready-made cell objects, rows can include one or two styles of text, often an image, and an accessory view of some sort.

The application can modify the text in its font, color, and other characteristics, and it can supply an image for the row in its selected state as well as its normal state. As flexible and useful as this cell content is, it might not satisfy the requirements of all applications. For example, the labels permitted by a native UITableViewCell object are pinned to specific locations within a row, and the image must appear on the left side of the row.

If you want the cell to have different content components and to have these laid out in different locations, or if you want different behavioral characteristics for the cell, you have two alternatives:. In a storyboard , the cells in a table view are dynamic or static. With dynamic content, the table view is a list with a large and potentially unbounded number of rows.

A table view that presents a detail view of an item is a good candidate for static content. You can design dynamic or static cell content directly inside a table view object. Figure shows the master and detail table views in a simple storyboard. In this example, the master table view contains dynamic prototype cells, and the detail table view contains static cells.

The following sections demonstrate how to load data into table views that contain custom-configured cells. In this section, you compose a custom prototype cell in a storyboard. At runtime, the data source dequeues cells, prepares them, and gives them to its table view for drawing the rows depicted in Figure The data source can use two different ways to access the subviews of the cells.

One approach uses the tag property defined by UIView and the other approach uses outlets. Using tags is convenient, although it makes the code more fragile because it introduces a coupling between the tag numbers in the storyboard and the code. Using outlets requires a little more work because you need to define a custom subclass of UITableViewCell. Both approaches are described here. This is the same reuse identifier you send to the table view in the dequeueReusableCellWithIdentifier: message.

For an example, see Listing For this example, drag two label objects and position them near the ends of the cell leaving room for the accessory view. Find this property in the View section of the Attributes inspector and assign each object a unique integer. For this example, the only data you need is the row number of each cell. Implement the data source method tableView:cellForRowAtIndexPath: to create a new cell from the prototype and populate it with data, in a manner similar to Listing Listing Adding data to a cell using tags.

The string identifier you assign to the prototype cell is the same string you pass to the table view in dequeueReusableCellWithIdentifier:. Because the prototype cell is defined in a storyboard, the dequeueReusableCellWithIdentifier: method always returns a valid cell. The code gets the labels in the cell by calling viewWithTag: , passing in their tag integers.

It can then set the textual content of the labels. If you prefer not to use tags, you can use an alternative method for setting the content in the cell. In the storyboard, associate the new class with the prototype cell and connect the outlets to the corresponding objects in the cell. Use the Connections inspector to connect the two outlets in the prototype cell to their corresponding labels. Listing Adding data to a cell using outlets. The code gains access to the labels in the cell using accessor methods dot notation is used here.

The code can then set the textual content of the labels. In this section, you compose several cells in a table view with static content. At runtime, when the table view is loaded from the storyboard, the table view controller has immediate access to these cells and composes the sections and rows of the table view with them, as depicted in Figure As with the procedure for dynamic content, start by adding a subclass of UITableViewController to your project.

Define outlet properties for the master row label in the first cell and the slider value label in the last cell, as shown in Listing Listing Defining outlet properties for static cell objects. In the storyboard, drag a Table View Controller object from the Library onto the canvas. Select the table view and set the following attributes in the Attributes inspector:. For each section in the table view, use the Attributes inspector to enter a string in the Header field.

Then for the cells, complete the following steps:. Delete two of the three cells in the first table-view section and one cell in the second section. Drag objects from the Library to compose the subviews of each cell as depicted in Figure Set any desired attributes of these objects. Select the table view controller and display the Connections inspector. Make connections between the three outlets in your table view controller and the corresponding objects, as shown in Figure To populate the data in the static cells, implement a method called configureView in the detail view controller.

In this example, detailItem is an NSString object passed in by the master view controller in its prepareForSegue:sender: method. The string contains the master row number. Listing Setting the data in the user interface.

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TableView With Custom Cells In Swift - Tutorial

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Uitableviewcell In this post, I am going to talk about some vital points uitableviewcell need to keep in mind as well as bonus tips in relation to cell reusability. Tells the accessibility system uitableviewcell dismiss a modal popover or hierarchically-displayed element. Whether this UIView can become the focused view. When you're doing an async operation in reusable views, a lot of things can go wrong. Description of the object, the Objective-C version of ToString. Specifies whether the UIView displays or not. Source true if this UIView is in the view 's view hierarchy.
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Tv stands cheapest Rest, everyone have their own code-of-style so I can't commit anymore. For example, let's look at this code inside the same configure method owned by MyTableViewCell. Determines whether the view is opaque or not. Returns an appearance proxy for here specified traits when found in the containers containment hierarchy. Uitableviewcell can fix the problem by comparing the input URL that you previously passed to download the image and the output URL provided by the closure once the download operation completes. Here is the modified code:. Uitableviewcell the resources used by the NSObject object.
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