Here is the code that I have in the viewcontroller that uses the plist information provided in my appdelegate.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [self.tableDataSource count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
}
NSDictionary *dictionary = [self.tableDataSource objectAtIndex:indexPath.row];
cell.text = [dictionary objectForKey:#"myobject"];
This uses the plist that is used in the appdelegate and populates the cells in my table with exactly how many entrances I have in my plist.
The next thing I want to do is push a nondynamic viewcontoller for each cell populated with its corresponding "key".
So, the myobject cell (when selected) pushes the myobject viewcontroller.
The yourobject cell (when selected) pushes the yourobject viewcontroller.
All the way down.
How could I go about doing this?
Have your main window contain a UINavigationController, and set the table view you described above as the root view controller.
Have your table view contain a member variable for your secondary view controller that will be the "detail view" for that item. Initialize it somewhere (such as viewDidLoad).
Have your detail view contain a member variable for the info to be displayed (i.e. the element in your dictionary). Let's call this myData.
Implement didSelectRowAtIndexPath in your table view to detect when a row is selected. Here you'll look up the object from the dictionary based on the selected row, set it as myData on your detail controller, and use pushViewController on your navigation controller to push the new view onto the stack.
Hope this helps!
Related
I'm working on an application that has multiple views, taking data from one view and storing it in a table in another. I have labels that are updated with data when a calculate button and a button that is hopefully going to store the data from those labels on their own cell in the UITable in another cell. I'm currently lost on how I would set up my UITable to create a new cell and pass the data to that cell every time the validate button is pressed.
This is basic MVC behavior. Table cells are loaded at display time in the UITableView datasource delegate methods. The data should be loaded from some type of store, in your case most likely an array.
When you want to update the data (from anywhere), simply update the data store (array).
Reload the UITableView at will with the reloadData method (or whenever the view appears).
So the idea is that you want to store your UILabels' text values in UITableViewCells on the press of a button?
If this is the case, I would store each text value as an element in an NSArray after every time your button is clicked, like so:
// Given:
// 1.) Your labels are IBOutlets
// 2.) Your labels follow the naming convention label1, label2, label3, etc
// 3.) You have an initialized class variable NSMutableArray *labels
// 4.) NUM_OF_LABELS_IN_VIEW is the number of UILabels in your view
// 5.) myTableView is an outlet to your UITableView, and its delegate and datasource are set to your view controller
-(IBAction)buttonPressed:(id)sender{
self.labels = [[NSMutableArray alloc] init];
for (int i=0; i < NUM_OF_LABELS_IN_VIEW; i++){
[labels addObject:[self valueForKey:[NSString stringWithFormat:#"label%i", i]].text ];
}
[self.myTableView reloadData];
}
And your data source methods should look something like this:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [self.labels count];
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = #"MyCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if(!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:Cellidentifier];
}
cell.textLabel.text = self.labels[indexPath.row];
return cell;
}
If the UITableView is in a separate view controller, just assign the NSArray *labels to a #property on the presenting view controller.
Basically I'm making a list view that you can add things to the top of. The best way I can think of doing this is to store the UITableViewCells themselves in a NSMutableArray — Because I can simply pull them from the array them with all their data inside the object, and this list view will never be over 10 cells long.
Also note that I'm using Storyboards, hence the initWithCoder use.
The following code is what I'm trying, and it doesn't work:
// This is where my NSMutableArray is initialized:
- (id)initWithCoder:(NSCoder *)aDecoder
{
if (self = [super initWithCoder:aDecoder]) {
if (!_CellsArray) {
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"TestCell"];
_CellsArray = [NSMutableArray arrayWithObject:cell];
}
}
return self;
}
//UITableView Delegate & DataSource Methods
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"TestCell"];
[_CellsArray insertObject:cell atIndex:0];
return [_CellsArray objectAtIndex:indexPath.row];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 10;
}
I realize I may be approaching this in the wrong way, that's why I'm here though :)
Thank you.
edit: fixed a type in the code (TimerCell -> UITableViewCell)
Let's look at the order things get called in and what happens.
Your view controller is unarchived, so your initWithCoder: method is called. This method creates a mutable array and puts one instance of TimerCell into it. Said instance is not further configured (unless you've overridden initWithStyle:reuseIdentifier: to do some configuration).
Your data source method tableView:numberOfRowsInSection: is called, and it tells the table view there are ten rows.
Thus, your tableView:cellForRowAtIndexPath: is called ten times. Each time, it creates a new instance of UITableViewCell and inserts it into your mutable array. (After ten calls, your mutable array contains one TimerCell at index 10 and ten UITableViewCells at indices 0-9.) It does nothing to configure the cell's contents or appearance, then it returns the cell at the specified row index. On the first call, you're asked for row 0, so the cell you just created and inserted at index 0 is returned. On the second call, you're asked for row 1, so the cell at index 1 in your array is returned -- since you just inserted a new cell at index 0, the cell you created on the last call has shifted to index 1, and you return it again. This continues with each call: you return the same unconfigured UITableViewCell ten times.
It looks like you're trying to out-think UIKit. This is almost never a good thing. (It's been said that premature optimization is the root of all evil.)
UITableView already has a mechanism for cell reuse; it's best to just keep track of your own cell content and let that mechanism do its thing. I took so long to type this that other answers have been written describing how to do that. Look to them, or to Apple's documentation or any third-party UITableView tutorial.
Why don't you just store the cell information in an array. Then in the -cellForRowAtIndexPath: method, just extract the data needed to change each cell.
Here is a simple example:
//Lets say you have an init like this that inits some cell information
- (id)initWithCoder:(NSCoder *)aDecoder
{
if (self = [super initWithCoder:aDecoder]) {
cellArray = [NSArray alloc] initWithObjects:#"firstCell",#"secondCell",#"thirdCell",nil];
}
return self;
}
//then for each cell, just extract the information using the indexPath and change the cell that way
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
// Configure the cell...
cell.textLabel.text = [cellArray objectAtIndex:indexPath.row];
return cell;
}
Table views don't store things. Rather, they just ask for the data they want to display, and you typically get that data from elsewhere (like an NSArray, or an NSFetchedResultsController). Just store the things you want into some data container, and let the table display them for you.
// Probably your data model is actually a member of your class, but for purposes of demonstration...
static NSArray* _myArray = [[NSArray alloc] initWithObjects:#"Bob", #"Sally", #"Joe", nil];
- (NSInteger) tableView:(UITableView*)tableView numberOfRowsInSection:(NSInteger)section
{
return [_myArray count];
}
- (UITableViewCell*) tableView:(UITableView*)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath
{
static NSString* CellIdentifier = #"TestCell";
// Make a cell.
UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if( cell == nil ) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
// Setup the cell with the right content.
NSString* aString = [_myArray objectAtIndex:[indexPath row]];
cell.textLabel = aString;
return cell;
}
Now if you want more stuff in the list, add it to your array, and you're done.
Edit: On another note, initWithCoder: isn't generally the best place to do initialization for a view controller. Reason being, at the point that it's called, there's a good chance that stuff isn't loaded yet (IBOutlets, for example). I tend to prefer viewDidLoad (don't forget to cleanup in viewDidUnload in that case), or awakeFromNib.
I unfortunately still have not seen the light when it comes to organising my iphone app nicely into controllers and views. Let me illustrate with an example:
I am working on a sign up page which consists of a table view with a list of custom table cells. Some of these cells have a text field inside them and when the user touches one of those a keyboard slides up from the bottom. The keyboard has a return key in its lower right corner and when the user hits this key I would like the keyboard to slide down again.
Now, where do I put the
- (BOOL) textFieldShouldReturn:(UITextField *)textField {
[textField resignFirstResponder];
return YES;
}
? Currently I have made my custom table cell conform to the text field delegate protocol and have put the method in there, but it does seem a bit wrong to have stuff like that inside a view class? On the other hand I do not find it appropriate in the table view controller either.
you can set your table view controller as the text field's delegate...
just remove the code in the custom cell where you set it as the delegate and instead set the delegate in the table view controller's cellForRowAtIndexPath method where you actually create and return the cell..
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"CellIdentifier";
MyCustomCell *myCell = (MyCustomCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (myCell == nil)
{
myCell = [[[MyCustomCell alloc] initWithStyle:UITableViewCellSelectionStyleNone reuseIdentifier:CellIdentifier] autorelease];
myCell.myTextField.delegate = self;
}
//other cell specific code goes here
return myCell;
}
I have a UITableView in that some cells are marked with UITableViewCellAccessoryCheckmark at the initialization of the view.
When the user selects another row, I have to check if the maximum number of selected rows was achieved before. To do that, I used the code bellow:
- (NSInteger)tableView:(UITableView *)tableView numberOfSelectedRowsInSection:(NSInteger)section{
NSInteger numberOfRows = [self tableView:tableView numberOfRowsInSection:section];
NSInteger numberOfSelectedRows = 0;
for (int i = 0; i < numberOfRows; i++) {
UITableViewCell *otherCell = [tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:section]];
if (otherCell.accessoryType == UITableViewCellAccessoryCheckmark) {
numberOfSelectedRows++;
}
}
return numberOfSelectedRows;
}
If my number of rows is, as example, 20, the variable numberOfRows is setted correctly with 20. Lets say that 13 rows already are marked with UITableViewCellAccessoryCheckmark. So, numberOfSelectedRows should be 13 after the loop, but only the marked and VISIBLE cells are considered. So, if I have 9 cells showed and 7 are marked, the numberOfSelectedRows returns 7 instead of 13 (but the for iterate 20 times, as expected).
Is this a correct behavior of UITableView or it is a bug of iPhone simulator?
Thanks in advance.
Yes, it works as designed. You should never store model data in your views. UITableView knows nothing about the data, it only displays cells (and throws them aways as soon as they scroll off the screen). You need to store the checkmark state of each cell in a model object (e.g. an array) that you then access from your view controller.
This is correct behavior.
The UITableView is not a list. The system caches cell that are off screen to save memory and CPU and they can not be iterated over in a manner that makes sense.
Ok, you should keep track of the model/data and the tableView will keep track of displaying it. I have had some problems with this until I accepted that uitableView is not a list:)
So, have an array of objects that each corresponds to the data in the a cell. When building the individual cells like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"categoryCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}
Item *item = [self.itemList objectAtIndex:indexPath.row];
[cell.textLabel setText:[item itemBrand]]; //notice that here we set the cell values
return cell;
}
The when a user clicks you change you model like this:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSLog(#"IndexPat.row%i", indexPath.row);
Item item = (Item*) [self.itemList objectAtIndex:indexPath.row];
//change the state of item
}
This way the tableView will update to resemble the model/data, you just managed the model.
I have a uitableview that is populated from a sqlite query.
I want to select or click on a row and then display that row's value in a uilabel field. To show the user that the row was selected.
I also want to pass that value on to different controllers that will be called later.
Here is a copy of my cellForRowAtIndexPath:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"psystem";
PSystem *psystem = [self.ppdm_systems objectAtIndex:indexPath.row];
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
// Set up the cell...
// self.accessoryType = UITableViewCellAccessoryCheckmark;
cell.textLabel.text = psystem.system_id;
return cell;
}
I took out the _label.text .... in my various experiments.
Now what is not working is the passing of the value to different controllers.
Using the example listed here, the source controller is TableViewController and is where the value is set. The target controller is DetailViewController.
I can pass the title of the tab bar in, but that's from TableView --> DetailView.
I am not sure how to pull from tableview; ie: Tableview <-- DetailView when I am in DetailView.
thx
In your UIViewController, implement:
- (MyObject *)valueForSelectedRow {
MyCell *cell = (MyCell *)[self.tableView cellForRowAtIndexPath:[self.tableView indexPathForSelectedRow]];
return cell.myObject;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Get value
MyObject *object = [self valueForSelectedRow];
// Update the label, assumed that _label is a pointer to a UILabel view object.
_label.text = object.myValue;
}
When you want to push a new view controller, you just call -valueForSelectedRow and then use that value to push the controller.
This is assumed that you have a UITableViewCell subclass, with a property set to some model object. When you don't have that and just set the text property, that NSString object will be your 'model' object, although it would be easier when your cells handle custom model objects.
EDIT: Thanks for editing your answer. I now have the information I need. In this line: cell.textLabel.text = psystem.system_id, you setup the cell by simply setting the textLabel's text property. This is what I described in the paragraph above. I always create a UITableViewCell subclass, with a property set the the complete PSystem object. When you assign a PSystem object to the cell, it will handle it's contents, so you can easily manage your view in the, well, view. That's a very compelled approach since you never have to look at the controller again to alter the view's contents.
However, it can be done the way you currently have it. It would look something like:
- (NSString *)valueForSelectedRow {
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:[self.tableView indexPathForSelectedRow]];
return cell.textLabel.text;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Get value
NSString *value = [self valueForSelectedRow];
// Update the label, assumed that _label is a pointer to a UILabel view object.
_label.text = value;
}
In this case, your PSystem model has been replaced with an NSString object. For this, it's enough, but it could be so much easier to have the object itself. Okay, that can also be done by selecting the PSystem object again from the p_system array by the NSIndexPath, but things will become harder once you come up with more complex tableviews.