In my app, i add a slider in Table view i.e. each row contains a slider & It also works fine.
But when i scroll the table view the slider get reload i.e. each shows me starting position rather than slider value.
//My code is as follow for slider in table cell:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *CellIdentifier=[NSString stringWithFormat:#"CellIdentifier%d",indexPath.row];
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier];
return cell;
}
UISlider* theSlider = [[[UISlider alloc] initWithFrame:CGRectMake(174,12,120,23)] autorelease];
theSlider.maximumValue=99;
theSlider.minimumValue=0;
[cell addSubview:theSlider];
return cell;
}
How can i solve this??
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *CellIdentifier=[NSString stringWithFormat:#"CellIdentifier%d",indexPath.row];
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier]; UISlider* theSlider = [[[UISlider alloc] initWithFrame:CGRectMake(174,12,120,23)] autorelease];
theSlider.maximumValue=99;
theSlider.minimumValue=0;
[cell addSubview:theSlider];
} return cell;
This way the slider gets created only when cell is nil i.e cell gets created. and use tableView:willDisplayCell:forRowAtIndexPath: method to set the slider value like slider.value = yourvalue;
You need to store values of slider view and set the values of sliderview in cellForRowAtIndexPath slider.value = yourvalue;
The problem is that cellForRowAtIndexPath is called not just once, but every time that the tableView need to render that cell... So you have to be sure that only initialize theSlider the first time is called...
The best approach is to define a custom UITableViewCell and put there a property that would store theSlider, then, when cellForRowAtIndexPath is called, check if it is already initialized or not, see:
// If the slider is not yet initialized, then do it
if(cell.theSlider == nil)
{
// Init...
}
This is really from "cellForRowAtIndexPath" method . Every time when you are scrolling every cell is getting nil and reinitialise it. Better you can try with creating custom cell class(BY creating sub class of UITableViewCell) and also the defining slider in condition "if (cell == nil)".
Related
When scrolling my UITableView (tends to be when I scroll it fast) the data for my cells gets mixed up, so labels might be repeated etc.
I understand that reusing the cells probably causes this, but what if the user scrolls down the list really quickly and all the cells get mixed up, how am I supposed to avoid this?
Thanks.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"VideoListCell";
VideoListCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[VideoListCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Configure the cell...
if (isPlaylistView)
{
//Fill cell with data
}
else if (isPlaylistDetailView || isSearchResultsView)
{
//Fill cell with data
}
else
{
//Playlist button and uploads
if (indexPath.section == 0)
{
//Fill cell with data
}
else
{
//Fill cell with data
}
}
return cell;
}
You generally use this kind of code:
cell = dequeReusableCell;
if (cell == nil) {
create cell;
initialize cell;
}
fill cell with actual data from current row
return cell;
If you will move code "fill cell with actual data from current row" into "if" — you will get the kind of behavior you get right now.
So the answer will be "fill cell with data after you initialize it, outside of "if (cell == nil)" block.
UITableView will ever only dequeue a cell for reuse if the position that the cell was in is currently off-screen. So you don't have to worry about "mix-ups".
static NSString *cellIdentifier=#"cell";
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if(cell==nil)
{
cell=[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:nil];
}
I think it will be helpful to you.
set dequeueReusableCellWithIdentifier to nil for example..
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:nil];
UPDATE:
See this Example... i load many data in the cell with also my custom Gridview...
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString* cellIdentifier = #"gridCell";
UITableViewCell *gridCell = [tableView dequeueReusableCellWithIdentifier:nil];
if(gridCell == nil)
{
gridCell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier] autorelease];
}
return gridCell;
}
hope this help you....
In your custom cell class override prepareForReuse method. In this method set text of your labels to nil and set imageview's image to nil also. This function is called everytime when a cell is reused so your problem will be solved by this. May be like this
- (void)prepareForReuse{
[super prepareForReuse];
self.titleLabel.text = nil;
self.unitImageView.image = nil;
}
Once the user taps a cell triggering an action, I want to disable the user interaction and then reenable user interaction when the action has finished. Can someone tell me how to do this?
Just check for the condition in TableView delegate method:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *categoryIdentifier = #"Category";
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
//Way to stop to choose the cell selection
if(indexpath.row == 0){
cell.selectionStyle = UITableViewCellSelectionStyleNone;
// OR
cell.userInteractionEnabled=False;
}
//while rest of the cells will remain active, i.e Touchable
return cell;
}
Just add a BOOL variable that you set to true when the action has started. Then implement the -[tableView:willSelectRowAtIndexPath:] method of the tableview's delegate so that it returns nil when the variable is currently true for that index path.
or you can make the selectionStyle when action is running
cell.selectionStyle = UITableViewCellSelectionStyleNone;
I was trying to place two uibuttons on uitableviewcell programmatically.. but unable to achieve that>. somehow i managed to get the buttons through some sample project in which u can draw a nib for cell.. but i was unable to set a selector function for buttons.. in other example i can place a uiinfodark type button but when i change the type to rounded rect the button gets disappeared and i am unable to figure out why? I might be doing some silly mistake but I am really kinda stuck with it right now so I'll be very much thankful to all of you for helping in this regard.
You will need a UITableViewDataSource
http://developer.apple.com/library/ios/#documentation/uikit/reference/UITableViewDataSource_Protocol/Reference/Reference.html
Then something like this
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"CellIdentifier";
// Dequeue or create a cell of the appropriate type.
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.accessoryType = UITableViewCellAccessoryNone;
}
// Get the object to display and set the value in the cell.
[cell addSubView: YOUR_BUTTON];
[cell addSubView: YOUR_OTHER_BUTTON];
return cell;
}
I have a view controller that gets presented modally and changes some data that effects the data in a uitableview in the modal's parent view controller (a table view).
I call the tableview's reloadData method when the parent view reappears. I have confirmed that this code gets hit with a break point. My trouble is, reloadData isn't working. Here's the kicker - if I don't use reuseIdentifiers in the - (UITableViewCell *)cellForRowAtIndexPath:(NSIndexPath *)indexPath method, the data reloads correctly. It looks like the reuseIdentifier is to blame.
I really want to continue to use the reuseIdentifier for my cells - how do I make this work?
Got it figured, and you're right, it's not the reuseIdentifer.
I was nesting the content assignment right below the cell allocation like so:
// Dequeue or create a cell of the appropriate type.
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.accessoryType = [targetRow.children count] ? UITableViewCellAccessoryDisclosureIndicator : UITableViewCellAccessoryNone;
// Configure the cell.
cell.textLabel.text = [NSString stringWithFormat: targetRow.title];
}
Since the dequeued cell was found, the content wouldn't get updated.
I changed it to this and all works great now...
// Dequeue or create a cell of the appropriate type.
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
cell.accessoryType = [targetRow.children count] ? UITableViewCellAccessoryDisclosureIndicator : UITableViewCellAccessoryNone;
// Configure the cell.
cell.textLabel.text = [NSString stringWithFormat: targetRow.title];
The problem is unlikely to do with the reuse identifier. Please post your code for your tableView:cellForRowAtIndexPath: method.
I just have a basic (noob) question about cellForRowAtIndexPath get called?
I'm working through example code and I don't see it explicitly called anywhere?
Does any component of type UITableViewComponent automatically call this function when it is created?
Thanks
When a UITableView is displaying this method gets called per row. In it you will customize each cell with particular data for display.
Here's the class reference.
Here's a sample:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"FriendCellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}
NSUInteger row = [indexPath row];
cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
Item *i = [itemArray objectAtIndex:row];
cell.textLabel.text = [i name];
cell.detailTextLabel.text = [i brewery];
[i release];
return cell;
}
This is called for each cell when the corresponding UITableView gets drawn. An index path is passed in, and based on the section and cell numbers, your code should generate a UITableViewCell to be displayed in the UI.
You can look here for a quick tutorial into how UITableViews work.