I have seen a lot of examples and I cannot find the best answer.
Imagine that I have a custom cell with a 120 height, with 3 UILabels and a UIImageView.
I init my cell with
-(id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
Of all the approaches, which one its the most optimum?
Probably the best answer for creating custom tables is at the link below, if you then have specific questions about the code you see there, then feel free to ask more questions.
http://cocoawithlove.com/2009/04/easy-custom-uitableview-drawing.html
All you have to do is something like this:
- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Prototype Cell"];
UILabel *label;
if (!cell)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:#"Prototype Cell"];
label = [[UILabel alloc] init];
label.tag = LABEL_TAG; //Suppose LABEL_TAG is defined someplace else
[cell.contentView addSubview: label];
}
else
{
label = [cell.contentView viewWithTag:LABEL_TAG];
}
label.text = #"Hello World";
//Suppose you want the label at x coordinate 50
label.frame = CGRectMake(0,0,50,120);
//Follow similar steps for all of your subviews
return cell;
}
Create a custom UITableviewCell by subclassing the UITableViewCell & overide the method initWithStyle.You can alloc the labels in this init method & also add this label in the cell in this method.
You can also create the UItableViewCell by using nib files.
http://ijoshsmith.com/2011/07/16/creating-a-custom-uitableviewcell-in-ios-4/
Related
In my application i need to display multiple images in a UITableView,so i've already searched a lot in the web for the proper way to load large images to UITableViewCells,to be more clearly i'll divide the procedure that my app execute:
Download images asynchronous;
Save them to NSHomeDirectory();
=> Thins part is working perfectly.
The problem is,how to display the images in the UITableViewCell,i've already tried to add UIImageView's to the cell contentView but the scrolling performance were a bit affected,i've searched on Apple guides and i believe the correct way is adding UIImageView's to the cell and loading the images from NSHomeDirectory(),so:
What's the best way to customize a UITableViewCell and add the UIImageView's(302x302px) to it?
To get the best scroll performance, you must draw the content of the UITableViewCell yourself.
Loren Brichter, the author of the Tweetie app (now the official Twitter app), wrote a very famous blog post on this. Sadly, this blog post has been deleted.
This article may help you, though. It explains the fast scrolling, it has examples and it has a video to a presentation from Loren Brichter.
Basically, what you want to do is to subclass UITableViewCell and override the drawRect:method. To show an image, you would do something like the following:
- (void)drawRect:(CGRect)rect
{
[myImage drawAtPoint:CGPointMake(10, 10)];
}
This way you avoid to layout a lot of subviews.
I have the same question.
I'm doing the following:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString* CustomCellIdentifier = #"CustomCellIdentifier";
CustomCell* cell = [tableView dequeueReusableCellWithIdentifier:CustomCellIdentifier];
if (cell == nil) {
cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CustomCellIdentifier];
}
// add subview to cell
if (cell.customView == NULL) {
cell.customView = [[CustomView alloc] initWithFrame:cell.frame];
[cell.contentView addSubview:cell.customView];
}
// bind cell data
return cell;
}
Firstly, you need to create a custom cells for UITableView & keep going through following points.
set height of each row to 302 pixels as
-(CGFloat) tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 302.0;
}
Use following code to create UIImageView at each cell of table
-(UITableViewCell*) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:#"cell"];
const NSInteger IMAGE_VIEW_TAG=1001;
UIImageView *imageView;
if(cell==nil)
{
cell=[[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell"] autorelease];
cell.accessoryType=UITableViewCellAccessoryDisclosureIndicator;
imageView =[[[UIImageView alloc] initWithFrame:CGRectMake(10, 0, 302, 302)] autorelease];
imageView.tag=IMAGE_VIEW_TAG;
imageView.contentMode=UIViewContentModeScaleAspectFit;
[cell.contentView addSubview:imageView];
}
imageView=(UIImageView*)[cell.contentView viewWithTag:IMAGE_VIEW_TAG];
[imageView setImage:[UIImage imageNamed:#"image.png"];
return cell;
}
set number of rows you want to display
-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 5;
}
dont forget to add TableView delegate and data source , UITableViewDelegate and UITableViewDataSource
In this screen shot you can see that I have added UITableView in UIViewController then customized the UITableViewCell by adding some labels in it. But the issue is when I run the application. All of the cells are empty. There are no labels at all.
I am not getting what can be the issue. I have searched the web and read tutorials but couldn't resolve it.
I resolved this issue by myself, just after little effort.
Actually when you create a custom cell you have to do these things:
Setup the labels, images etc on storyboard cell.
Create a custom cell class (inheriting from UITableViewCell)(CustomCell.h & .m), CustomCell.h having all of the properties as iboutlet for labels, images etc. and synthesize them all in implementation.
After creating this custom class go back to storyboard, select the custom cell, change its class to the CustomCell and give it some identifier like "MyCustomCell", then right click on the custom cell and connect the IBOutlets with labels etc.
Now import CustomCell class in the class where you are implementing the UITableView and use the properties you defined in CustomCell class.
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *MyIdentifier = #"MyCustomCell";
CustomCell*cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:MyIdentifier] autorelease];
}
// Here we use the provided setImageWithURL: method to load the web image
// Ensure you use a placeholder image otherwise cells will be initialized with no image
[cell.imageView setImageWithURL:[NSURL URLWithString:#"http://example.com/image.jpg"]
placeholderImage:[UIImage imageNamed:#"placeholder"]];
cell.myCustomLabel.text = #"My Text";
return cell;
}
I did this all and my issue was resolved and please don't forget to connect the delegates & datasource and table.
Hope this will help others.
It is little bit late but you can solve your problem by setting the background color of your view as Clear Color from your storyboard.
in the tableview's delegate method , cellforrowatindexpath has a uitableviewcell inside it , there should be an identifier in the initialization of this cell. possibly it is "cell" or "cellIdentifier" .
you just need to select your cell from storyboard and enter this identifier string to the storyboard , where uitableviewcell's attribute inspector stays.
hope this helps.. :)
First Set cell identifier in storyboard #"Cell"
then set tag of label
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// Create
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] ;
}
UILabel *lblDate = (UILabel*)[cell viewWithTag:101];
UILabel *lblDistance = (UILabel*)[cell viewWithTag:102];
UILabel *lbltype = (UILabel*)[cell viewWithTag:103];
lblDate.text = [temp objectAtIndex:indexPath.row] valueForKey:#"date"] stringByReplacingOccurrencesOfString:#"-" withString:#"/"]];
lblDistance.text = [NSString stringWithFormat:#"%# KM",[[temp objectAtIndex:indexPath.row] valueForKey:#"distance"]];
NSString *type = [NSString stringWithFormat:#"%#",[[temp objectAtIndex:indexPath.row] valueForKey:#"distance"]];
if([type isEqualToString:#"0"])
{
lbltype.text = #"Personal";
}
else
{
lbltype.text = #"Bussiness";
}
// Configure
return cell;
}
I have a table cell to which I'm adding subviews programmatically. All the textual subviews work fine, but I can't get an image subview working at all.
You'll notice that I set the background color to black. This is simply to indicate to me that the subview is indeed being initialized and positioned properly within the cell. When I remove the background color there is nothing there.
Also, the cell style is UITableViewCellStyleDefault but I don't think that's pertinent for custom subviews. I want the image positioned on the right, which is why I'm not using the standard imageView property that cells offer.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
// ... add textual views ...
UIImageView *img = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"clock.png"]];
img.frame = CGRectMake(271.0f, 10.0f, 19.0f, 22.0f);
img.backgroundColor = [UIColor blackColor];
[cell addSubview:img];
}
// ... more code ...
return cell;
}
Your code looks fine to an extent. One issue I had when I was creating my own UITableViewCells in code was I was creating the cells with variables like you are but you shouldn't do this.
What you should do is create the cell and then set the variables. If cells are different you should use different reuse identifiers. Hope this makes sense if not let me know and I'll update.
I have a UITableView where I have the backgroud color set via
UIView *myView = [[UIView alloc] init];
if ((indexPath.row % 2) == 0)
myView.backgroundColor = [UIColor greenColor];
else
myView.backgroundColor = [UIColor whiteColor];
cell.backgroundView = myView;
[myView release];
The problem I find is that when I edit a table (via setEditing:YES...) some cells of the same color invariable are next to each other. How do I force UITableView to fully redraw. reloadData is not doing a great job.
Is there are deep-cleaning redraw?
I had this issue before so I'll share with you how I solved it:
You can use a boolean flag (say it's called needsRefresh) to control the behavior of cell creation in -cellForRowAtIndexPath:
An example:
- (UITableViewCell*) tableView:(UITableView *) tableView cellForRowAtIndexPath:(NSIndexPath*) indexPath {
UITableViewCell *cell = [tableView dequeueResuableCellWithIdentifier:SOME_ID];
if(!cell || needsRefresh) {
cell = [[[UITableViewCell alloc] init....] autorelease];
}
//.....
return cell;
}
So, when you need a hard reload, set the needsRefresh flag to YES. Simple as a pimple.
For me the accepted answer didn't really work since I had no idea when to set the needsRefresh back to YES.
What worked for me was:
- (UITableViewCell*) tableView:(UITableView *) tableView cellForRowAtIndexPath:(NSIndexPath*) indexPath {
UITableViewCell *cell = [tableView dequeueResuableCellWithIdentifier:customCellIdentifier];
if(nil == cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:customCellIdentifier];
}
//.....
return cell;
}
And then you change the customCellIdentifier value whenever you need to. This way the cells are also still reusable if you switch back to the original cell identifier.
The accepted method seems dirty, it just makes a bunch of new cells that are stored along with the bad ones. Here are a couple of solutions depending on your situation:
1.
first, for the situation described in the question you should not dump your cells and create new views on every cycle. You need to tag your view and then get it back when from the cell when you get a reuse cell:
- (UITableViewCell*) tableView:(UITableView *) tableView cellForRowAtIndexPath:(NSIndexPath*) indexPath {
UITableViewCell *cell = [tableView dequeueResuableCellWithIdentifier:SOME_ID];
if(!cell) {
cell = [[UITableViewCell alloc] init];
UIView *myView = [[UIView alloc] init];
cell.backgroundView = myView;
[myView setTag:5]; //<------
}
UIView *myView = [cell viewWithTag:5]; //<------
if ((indexPath.row % 2) == 0)
myView.backgroundColor = [UIColor greenColor];
else
myView.backgroundColor = [UIColor whiteColor];
return cell;
}
//then just reload the tableview.
2.
...or even better, why not just use the cell backgrouncolor and update that without creating a view.
3.
A sure way to really clear out old cached cells it to simply recreate the UITableView object.
4.
In most cases you dont need to destroy these cells, just keep track of your elements and update them after getting the reusable cell.You can tag all your elements, keep a array reference to them, find them thought the view hierarchy... Im sure theres a bunch of other ways.
5.
heres a one liner to directly purge all cells, although not best practice to mess with the internals of objects like this as they might change in future versions:
[(NSMutableDictionary*)[tableview valueForKey:#"_reusableTableCells" ] removeAllObjects];
I was able to solve this by adding a refresh variable to the table datasource. I used a dictionary for each cell, but there's an extra key called #"refresh":#"1", indicating the cell needs refreshing. Once it's updated, I set that key's value to #"0". So whenever the table is reloaded, make sure the key goes back to #"0" again.
#define TABLE_VIEW_CELL_DEFAULT_ID #"cellIdentifier"
#property (nonatomic, strong) NSString *tableViewCellIdentifier;
#property (nonatomic) NSUInteger tableViewCellIdentifierCount;
// By using a different cell identifier, this effectively flushes the cell
// cache because the old cells will no longer be used.
- (void) flushTableViewCellCache
{
self.tableViewCellIdentifierCount++;
self.tableViewCellIdentifier = [NSString stringWithFormat:#"%#%i", TABLE_VIEW_CELL_DEFAULT_ID, self.tableViewCellIdentifierCount];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:self.tableViewCellIdentifier];
if (cell == nil) {
cell = [[MyTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:self.tableViewCellIdentifier];
}
// rest of method...
}
I want my UITableViewCell to look like the image below where there seems to be two labels. Is this possible without subclassing UITableViewCell?
alt text http://img31.imageshack.us/img31/2764/photoobp.jpg
There are different styles of UITableVieWCell. See here:
https://developer.apple.com/documentation/uikit/uitableviewcell/cellstyle
I think you want to use UITableViewCellStyleValue1.
You can initialise your UITableViewCell with the relevant style:
https://developer.apple.com/documentation/uikit/uitableviewcell/1623276-init
When you use a style that has two labels, you can use the textLabel and detailTextLabel properties to set them, respectively.
You do not need to subclass a UITableViewCell in order to add content to it. Here could be a sample cell generation method with an extra label:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *identifier = #"Identifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier] autorelease];
UILabel *secondLabel = [[UILabel alloc] initWithFrame:cell.textLabel.frame];
secondLabel.textAlignment = UITextAlignmentRight;
secondLabel.tag = 12345;
[cell.contentView addSubview:secondLabel];
}
UILabel *second = [cell viewWithTag:12345];
second.text = #"Second!";
return cell;
}
Let me know if you have any questions. I can clarify some things if needed.
Not sure where u think you see 2 labels...you can set the UILabels number of lines property if you want more lines UILabel ref....Also there is a UITableViewCell type UITableViewCellStyleSubtitle
which contains a detailTextLabel on top of the regular text labels in UITableCell, so you already have a built in cell with 2 text fields, here is a ref ref to UITableViewCell
Its not 2 labels but 2 buttons, you need to add 2 buttons in contentView view of the cell. Or you can create a footer or header View and add these 2 buttons.