I'm trying to add a data source inside a UITableView. I tried the following, but unfortunately it didn't work:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 8;
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Set the data for this cell:
cell.textLabel.text = [_classCellview objectAtIndex:indexPath.row];
cell.detailTextLabel.text = #"One";
cell.detailTextLabel.text = #"Two";
// set the accessory view:
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
cell.textLabel.text = [_classCellview objectAtIndex:indexPath.row];
You're telling the table that there are 8 sections, but you're not taking the section from the index path into account when you populate the cell. An index path has (in the case of a table view) two values: a section and a row. You need them both to know what cell you're dealing with. So, you're probably getting the same content repeated in each section of your table. (It'd help if you told us exactly what the problem is, though.)
Related
Here's where the magic isn't happening:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"songCell";
songViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
// Configure the cell...
long row = indexPath.row;
if (cell == nil) {
cell = [[songViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
if (tableView == self.searchDisplayController.searchResultsTableView) {
cell.songLabel.text = _searchResults[row];
} else {
cell.songLabel.text = _songListArray[row];
}
return cell;
}
I know the _searchResults array is populated with the correct search results and I've edited the numberOfRowsPerSection appropriately. The filter is working correctly, but it won't display the _searchResults[row] text while typing into the search bar. If I don't use the bar, the cells are populated correctly with _songListArray[row].
Something is going wrong in:
if (cell == nil) {
cell = [[songViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
If I don't include the if expression, I get an error. How should I initialize the prototype cell while the search bar is in use? All I get is empty labels, but I know the search is working because if there are no filtered results in the array the table says "No Results" in the middle. Why isn't my songLabel.text updating?? It won't even display text when I set the label to #"HELLO??" instead of the array[row].
You need to have the searchResultsTableView dequeue a cell, not just your main table view. The cellForRowAtIndexPath method should look something like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
if (tableView == self.tableView) {
RDTriangleCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
cell.textLabel.text = self.theData[indexPath.row];
return cell;
}else{
UITableViewCell *cell = [self.searchDisplayController.searchResultsTableView dequeueReusableCellWithIdentifier:#"SearchCell" forIndexPath:indexPath];
//RDCell *cell = [self.searchDisplayController.searchResultsTableView dequeueReusableCellWithIdentifier:#"SearchCell" forIndexPath:indexPath];
cell.textLabel.text = self.filteredData[indexPath.row];
return cell;
}
}
In viewDidLoad, you should register the class if you use the code I show above for a standard UITableViewCell.
[self.searchDisplayController.searchResultsTableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"SearchCell"];
If you use a custom cell for the search results table, then you should use something like the line I have commented out, and register the nib for that custom cell.
I fill my tableView with random data. So i don't know how many row i have and how to redirect it to screen i want to. I filled:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
MyClass *currentScreenElement = [self.tableRows objectAtIndex:indexPath.row];
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:currentScreenElement.objectName];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:currentScreenElement.objectName];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}
cell.textLabel.text = currentScreenElement.objectName;
return cell;
}
And this works fine. I have a tableView with filled rows. Now i want to redirect to new screen and I doing it with:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NewScreenClass *myScreen = [[NewScreenClass alloc] init];
self.detailViewController = [[CreateView alloc] initWithScreenDef:[myScreen returnScreenFromName:#"second"]];
[self.navigationController pushViewController:self.detailViewController animated:YES];
}
Of course i know that what I actualy do here is create the same screen for every row. But how can i redirect to screen i want to?
My currentScreenElement object contains properties: objectName (display name in tableView) and objectTarget (screen definition). Both NSString.
And my question is should i save a my currentScreenElement to row patch somehow or maybe I should catch a objectName from dislay name?
In didSelectRowAtIndexPath you can get the cell by using
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
Then just get the text from the cell.
cell.textLabel.text
Why can't you use the self.tableRows array again?
MyClass *currentScreenElement = [self.tableRows objectAtIndex:indexPath.row];
NSString *title = [currentScreenElement objectName];
It's the same thing you did to setup that row, just use it again.
So I'm using mogenerator with Core Data, the resultsController returns good objects with valid attributes when I first load the tableview. But when I scroll the table, all the reloaded cells are populated with objects with null attributes returned from resultsController. Is it some caching issue?
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Configure the cell...
Log *log = [self.resultsController objectAtIndexPath:indexPath];
cell.textLabel.text = [NSString stringWithFormat:#"%#", log.text];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
Turns out I shouldn't put the resultsController in the viewWillLoad or viewDidLoad. I put it into it's own access method and it works fine now.
Okay, I am having another UITableView problem. For some reason the indexPath.row is all jumbled up. When I comment out the if statement that sets up the cell, everything works fine. The NSLogs tell me that they are loading in order, but all the cells are out of order.
It also seems as if they repeat; I only see 8 cells, and they repeat over and over.
Here's my code:
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
NSLog(#"row: %d",indexPath.row);
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.backgroundColor = [UIColor clearColor];
cell.contentView.backgroundColor = [UIColor clearColor];
// Add subviews like this:
// [[cell contentView] addSubview:objectName];
// And I get the row number like this: indexPath.row when getting objects from the array
}
return cell;
}
To use your code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
NSLog(#"row: %d",indexPath.row);
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.backgroundColor = [UIColor clearColor];
cell.contentView.backgroundColor = [UIColor clearColor];
// Add subviews like this:
// [[cell contentView] addSubview:objectName];
}
### Move this here ###
// And I get the row number like this: indexPath.row when getting objects from the array
return cell;
}
" I only see 8 cells, and they repeat over and over." Correct.
What your missing is that that is how it is supposed to work. That's why only if the cell is nil are you alloc & init'ing a new cell. So you alloc and init and set the colors and add subviews in the if statement. Then after the if(cell==nil) you know you have a valid cell to populate with some data according to the indexPath variable passed in.
The problem is that now you are setting up the cell when it is nil and assigning all of the displayed data according to the indexPath passed in. The problem is cell is not nil the second time it's used so the data is never changed.
To address your speed comment further, I'll use an old fallback example.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
UILabel *hugeLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, cell.frame.size.width, cell.frame.size.height)];
hugeLabel.tag = 300;
[cell addSubview:hugeLabel];
}
[(UILabel *)[cell viewWithTag:300] setText:[arrayOfStrings objectAtIndex:indexPath.row]];
return cell;
}
If you look at the sample above, you'll see that we add a UILabel to the cell setting it's tag to 300. Then after the if statement we will have either a brand new cell or a reused cell with text already in the label. No matter either way we simply change the text of the existing label to whatever it should be considering the row. In this way we avoid creating views over and over.
If you are dead-set on caching your UITableViewCells you could do so like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row < _cells.count){
return [_cells objectAtIndex:indexPath.row]; // _cells is an NSMutableArray setup in viewDidLoad
}
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#""];
cell.textLabel.text = [source objectAtIndex:indexPath.row]; // source is an NSArray of NSStrings I set up in viewDidLoad
[_cells addObject:cell];
return cell;
}
Note When running this on device don't be surprised when in the console you see Received memory warning What's efficient & what's easy are often not the same.
The way you have it set up now, cell.selectionStyle, cell.backgroundColor, and cell.contentView.backgrounColor, etc., only get set when if (cell == nil) is true. You need to move that code outside the if statement block, so that it gets called both when dequeueReusableCellWithIdentifier: produces a cell and when it has no cells in inventory and produces nothing (i.e., nil).
How do I create an item in my datasource using a cell that is UITableViewCellStyleValue1? Do I have to create my own custom cell to do it? I don't see anything in the sample catalog.
thank,
howie
A new table item cell was added that emulates the table settings cell style. see https://github.com/facebook/three20/pull/682
You can either merge it manually or wait for the next three20 release which will hopefully include this change.
The point of using UITableViewCellStyleValue1 is that your using a pre-defined layout, so no you don't use a custom layout.
Example:
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier] autorelease];
}
// Configure the cell.
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
cell.textLabel.text = #"SettingLabel";
cell.detailTextLabel.text = #"SettingValue";
return cell;
}