How to set UITableViewCell highlighted image - iphone

I want to launch a method every time when user just highlights a cell (doesn't select it) in UITableView. Could you tell me please, how is it possible to do this ?
I want to do it because I have a custom cell with a pictures on it and I want to change pictures every time when user highlights the cell.
UPD: By highlight I mean that user just highlights a cell and don't release the finger from it. By select I mean when didSelectRowAtIndexPath is being launched (so the user releases the finger from the cell after he presses on it)

How do you envisage the user would 'highlight' a cell rather than 'selecting' one?
In iOS (or any touch based environment really) there is no concept of just highlighting a cell rather than selecting one. The only callback you get when the user touches a cell is didSelectRowAtIndexPath:
It might be worth reading up on the documentation on tables here.
UPDATE:
Ah OK, in that case you want to set the highlightedImage property of the cells imageView a bit like this;
cell.imageView.image = [UIImage imageNamed:#"normal_image.png"];
cell.imageView.highlightedImage = [UIImage imageNamed:#"highlighted_image.png"];

I didnt understand your question..you dont you want to use the method selectRowAtIndexPath?
if you want to execute a method when user select a row:
-you can use the method selectRowAtIndexPath and execute your method.
you can also create an invisible UIButton inside cell and when click in a cell you will click in button and execute your method . . .

From iOS 6.0, UITableViewDelegate has 3 methods to handle cell highlighting:
- tableView:shouldHighlightRowAtIndexPath:
- tableView:didHighlightRowAtIndexPath:
- tableView:didUnhighlightRowAtIndexPath:
You should use them, like in this example:
- (BOOL)tableView:(UITableView*)tableView shouldHighlightRowAtIndexPath:(NSIndexPath*)indexPath
{
return YES;
}
- (void)tableView:(UITableView*)tableView didHighlightRowAtIndexPath:(NSIndexPath*)indexPath
{
MyTableViewCell* cell = (MyTableViewCell*)[tableView cellForRowAtIndexPath:indexPath];
cell.myImageView.image = [UIImage imageNamed:#"myCellHigh"];
}
- (void)tableView:(UITableView*)tableView didUnhighlightRowAtIndexPath:(NSIndexPath*)indexPath
{
MyTableViewCell* cell = (MyTableViewCell*)[tableView cellForRowAtIndexPath:indexPath];
cell.myImageView.image = [UIImage imageNamed:#"myCellUnhigh"];
}

Related

how to set hidden property to NO for particular cell in tableView

I am new to iphone.I have a small doubt that is,I have a table view with 66 rows initially i placed a progress view to all rows but in viewdidload i set it to hidden for all those like below in tableViewClass(ShowProgressViewCont)
cell.progressView.hidden = YES;
here (cell) is the the reference of the CustomCell class.In this class i declare a progress view and setter and getter properties also be set here in this class
here in tableview there is a download button in each cell.If we click on that download button(for example in 66th cell).we have to remove the hidden property to the progress view for that particular 66th cell only.The remaining 65 cells should have the progress view in hidden only like that for all cells.
If any body know this please help me....
Are you familiar with the concept of table cells being reused?
viewDidLoad is not an appropriate place to manipulate the content of a single cell. It may work fine if the table is so small that all of its cells fit on the screen (in both orientations).
When there are more cells in the table than beeing displayed on the screen, then those cell that became invisible recently is being reused and displayed again.
So if there are 6 cells on the screen at a time then table cell no. 7 (sometimes 8) will be identical with cell no. 1.
cellForRowAtIndexPath would be a better place to hide/unhide certain views of a cell.
If it is a custom cell already then the cell's layoutSubViews could be appropriate, too. However, only in the tableViewController's cellForRowAtIndexPath you will have easy access to both, the table's data and the associated cell.
cellForRowAtIndexPath is called every time when a cell is about to become visible. Use the default reusing-mechanism to ensure that a proper cell object will be reused. It is pretty much straight forward.
Get the cell at index 65 and then cast it to your custom cell
UITableViewCell *cell = [tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:64 inSection:0]];
YourCustomCell *customCell = (YourCustomCell *)cell;
customCell.progressView.hidden = NO;
First set the row number in your download button in CellForRowAtInedexPath
downloadButton.tag = indexPath.row
[downloadButton addTarget:self action:#selector(actionDownload:) forControlEvents:UIControlEventTouchUpInside];
in actionDownload, make the IndexPath from button.tag and get the cell from "cellForRowAtIndexPath:",
finally update via reloadRowsAtIndexPaths: withRowAnimation:
Hide your progress view in your custom cell means make the default property of every progress view is hidden ,and then your button click method .
CutomeCell *cell = (CutomeCell *)[[button superview] superview];
[cell.progressView setHidden:NO];
NSIndexPath *rowToReload = [[self tableView] indexPathForCell:cell];
NSArray* rowsToReload = [NSArray arrayWithObjects:rowToReload, nil];
[UITableView reloadRowsAtIndexPaths:rowsToReload withRowAnimation:UITableViewRowAnimationNone];
may this help you ...
your model should be tracking the progress for every button clicked. for purposes of this answer, let's say the model is held in a property called modelInformationArray (which would contain an array of objects that relate to each cell in the table)
when the download button is clicked for a cell, modelInformationArray is modified in such a way that its object knows a download is being processed for it.
that object reports the downloading processing in a member called downloadingProcessingStarted. there are many other ways to do that part.
to get to the answer to your question … to then unhide the progress view, you would do something as follows in your UITableViewDataSource implementation of tableView:cellForRowAtIndexPath: .
- (UITableViewCell*)tableView:tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath {
YourCustomCell* cell = ...
if ([[self.modelInformationArray objectAtIndex:indexPath.row] downloadingProcessingStarted])
cell.progressView.hidden = NO;
}

UITableView...the correct way

I'm trying to make a UITableView like the native calendar app:
but I'm trying to learn the best way to do this. I'm able to get this for the most part with a switch statement in the cellForRowAtIndexPath method, but I'm having troubles changing the textColor when a cell is selected.
For some reason cell.isSelected is always NO, and I have no way to reload the tableview after another cell is selected anyway.
Should I subclass UITableViewCell for something this simple and store an array of cells?
Any help would be appreciated, thanks.
There is no need to subclass, as stated in the app doc the delegation function:
tableView:willSelectRowAtIndexPath:
should do the trick
EDIT:
Below you find some code that should demonstrate the idea of using the delegate. Please note that this code is untested, as i am currently not in front of my xcode.
-(void)willSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (prevIndexPath != nil) {
UITableViewCell* prevCell = [self.tableView cellForRowAtIndexPath: prevIndexPath];
prevCell.textLabel.textColor = [UIColor black]; // your initial color here
}
UITableViewCell* cell = [self.tableView cellForRowAtIndexPath: indexPath];
cell.textLabel.textColor = [UIColor green];
prevIndexPath = indexPath;
}
Make sure to set the UITableViewDelegate protocol to your controlling class that manages your TableView and set the tableViews.delegate to that.
To make this code run, you also have to define a property or variable with the name prevIndexPath. This ones holds the previously selected cell that is needed to revert to the cell to its initial color.

UITableView reload cells' view

How can I reload the whole tableview? In -tableView:cellForRowAtIndexPath: I'm comparing data online with data on user's device and if it's not the same then I am displaying a button to download content. After actions connected to this button I'd like to refresh the whole tableview to complare again the content online with local one.
reloadData does in fact update values but it doesn't remove these buttons. I'd like to change the way cells are displayed..
In other words I want this condition (in -tableView:cellForRowAtIndexPath:) to work and it doesnt:
if (![[NSFileManager defaultManager] fileExistsAtPath:someDir isDirectory:nil]) {
UIButton *bt = [UIButton buttonWithType:UIButtonTypeRoundedRect];
(...)
[cell addSubview:bt];
}
To update the table now I have to pop the viewcontroller and push it again. I'd like to do it with button on navBar.
Thanks in advance.
That is because you are caching cells with dequeueReusableCellWithIdentifier. Check the docs. You should cache 2 types of cells, with and without the button.
UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier: #"your-id"];
if (cell)
{
//Check if it should contain a button. If it shouldn't remove it
}
else
//Create a fresh new cell

UITableViewCell selector setSelected:animated: gets called many times?

I've discovered a strange behavior with setSelected:animated: in my custom UITableViewCell class. I discovered that this function gets called multiple times if I click on a cell in my table. I am wondering if this is normal behavior or a bug in my code.
To help with debugging, I've modified the setSelected:animated: function in my custom UITableViewCell class implementation as such:
- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
[super setSelected:selected animated:animated];
// Configure the view for the selected state.
if (selected)
NSLog(#"Yes %X", &self);
else
NSLog(#"No %X", &self);
}
If I click on a cell in the simulator, here is what I get in the console:
2011-03-22 22:05:26.963 marketPulse[3294:207] Yes BFFFDDD0
2011-03-22 22:05:26.964 marketPulse[3294:207] Yes BFFFDE30
You would think that I would get only 1 entry, since I only clicked on 1 cell.
And if I click on a different cell after that:
2011-03-22 22:07:11.014 marketPulse[3294:207] No BFFFD890
2011-03-22 22:07:11.016 marketPulse[3294:207] No BFFFDD00
2011-03-22 22:07:11.017 marketPulse[3294:207] Yes BFFFDDD0
2011-03-22 22:07:11.017 marketPulse[3294:207] Yes BFFFDE30
If I click on the same cell 2 times in a row, I get more than 2 Yes:
2011-03-22 22:08:41.067 marketPulse[3294:207] Yes BFFFDDD0
2011-03-22 22:08:41.068 marketPulse[3294:207] Yes BFFFDE30
2011-03-22 22:08:41.069 marketPulse[3294:207] Yes BFFFDE30
The more times I click the same cell, the more Yes I will get, and if I click on a different cell after that, I'll get a lot of No
I put a breakpoint before the NSLog, and looking at the debugger, it seems that all the repeated calls are coming from the same object.
Here is a part of my tableView:cellForRowAtIndexPath: function so you can see how my cells are being treated:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *ContentCellIdentifier = #"newsTableCellContent";
UITableViewCell *cell;
//index of cell data in tableData
NSUInteger index = indexPath.row / 2;
...
//content of story
else if( [indexPath row] % 2 == 1 ) {
cell = [tableView dequeueReusableCellWithIdentifier:ContentCellIdentifier];
if (cell == nil) {
NSArray *topLevelObjects = [[NSBundle mainBundle]
loadNibNamed:#"newsTableCells"
owner:nil options:nil];
for (id currentObject in topLevelObjects) {
if ( [currentObject isKindOfClass:[newsTableCellContent class]] ) {
cell = currentObject;
break;
}
}
}
((newsTableCellContent *)cell).content.text = [[tableData objectAtIndex:index] description];
}
return cell;
}
Everything works fine so its hard to tell if the repeat calls to setSelected:animated: are intentional or not. If this is normal operation, I can make do with another method, but I would just like to know if this is suppose to happen or not.
Thanks
What's going on is simply that the UITableView keeps track of which cells are selected in the table.
Since cells are reused when you scroll through a large table view, the table view has to keep the list of selected cells separate. Not only that, but whenever it reuses a cell it has to set its selected property, because it may be using an old, invalid selected state from a previous incarnation.
When you tap a cell, several things happen: the previously selected cell is deselected (using setSelected:). The new cell is highlighted. It's de-highlighted (at least if you tap, instead of holding your finger down), and the setSelected: method is called because the new cell was selected. That's one.
The second call is a delayed perform call, possibly from a point where the table view didn't yet know what the final state of the table would be. This call goes to _selectAllSelectedRows, which, as the name suggests, calls 'setSelected:animated:' on all selected rows. That's the second call. The reason for this is most likely to address potential issues due to the the table view being in a "transition", but who knows.
Whether it's a bug or not is up for interpretation. A fix for the duplicate calls is to simply do:
if (self.selected == selected) return;
right before the call to super (you do not have to call super if self.selected == selected).
This is a normal behavior if you're using iPad. (it is only called once on iPhone).
In order to stop getting multiple "setSelected:YES" or multiple "setSelected:NO", all you have to do is this:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
Now, 1 click on any cell gives you:
1 entry of setSelected:YES animated:NO
1 entry of tableView: didSelectRowAtIndexPath:
1 entry of setSelected:NO animated:YES
So, calls are now stable regardless of what you do.
Ideally you should not be calling setSelected from anywhere in your code.
UIKit will take care of calling it.
If you want to show a cell/row as selected in cellForRowAtIndexPath method simply call
tableView.selectRowAtIndexPath(indexPath, animated: true, scrollPosition: .None)
for that specific indexPath.
Again never ever call setSelected explicitly unless you really mean to.
It should definitely be called when table is scrolled. Cells are reused, that means, if you scroll cells in invisible areas will be reused and reinitialized, including the call to setSelected, which is basically a lightweight property setter.
If you really want to see what's happening, add a NSLog to tableView:cellForRowAtIndexPath: which will log indexPath and the returned cell.
The entire log should give you a good understanding what happens inside and why.
I suppose it will be something like this (Clicked on IndexPath 1:1)
Give me cell on 1:0 (previously selected cell).
Deselect 1:0
Give me cell on 1:0 again (updated after deselection)
Deselect 1:0 (update selected flag on this cell and trigger animation)
Give me cell on 1:1
Select 1:1
Give me cell on 1:1 again (updated after selection)
Select 1:1 (update selected flag on this cell and trigger animation)
Clicking on a selected cell again is only slightly different - instead of triggering unselecting, it triggers another update.

Is it possible to accept a button tag to be in some range iphone sdk

In my application I'm doing dynamic resizing of cells and label in it depending upon the text in it.
I'm adding button to cells in uitableview.
I'm taking the label instance and button instance in a new label and button variable respectively and setting their frames to arrange them properly after resizing.
if(cel==nil)
{
//some code
original_label=[[UILabel alloc]init];
original_label.tag=111;
//SOME MORE CODE GOES HERE
original_button=[[UIButton alloc]init];
original_button.tag=222;
//SOME MORE CODE GOES HERE
}
new_label=(UILabel *) [cell viewWithTag:111]; //This' how I'm taking the label instance on cell and below button instance on cell in new variables
new_button = (UIButton * ) [cell viewWithTag:222];
Earlier I kept the tags of all the buttons on cells same, so it was easier to get button instances on cells properly and were being arranged properly. But now I want to recognize these buttons separately as I'm adding some functionality on button_click. I'm giving the buttons that are added to the cells incremental tags[1,2,3...9 and so on]. Now, how can I take these button tags in some range like[suppose 1-9]?
Can anybody help?
Thanks in advance.
You can keep the button tags the same as you had before.
Instead, in the button_click method, figure out which row the button is in like this:
- (void)button_click:(UIButton *)button
{
UITableViewCell *cell = (UITableViewCell *)[[button superview] superview];
NSIndexPath *indexPath = [tableView indexPathForCell:cell];
//code to handle this indexPath.section and indexPath.row...
}
This assumes you have added the button to cell.contentView which is what the first superview gets. The second superview gets the cell.
The addTarget for the button should look like this (note colon after button_click):
[original_button addTarget:self action:#selector(button_click:) forControlEvents:UIControlEventTouchUpInside];