1. EEC-492/693/793 iPhone Application Development
Lecture 12
Wenbing Zhao & Nigamanth Sridhar
4/9/2019
EEC492/693/793 - iPhone Application Development

2. Outline More on table views
Using table view & navigation controller together
Assignments:
The push and pop app
Continue building the calculator app
4/9/2019
4/9/2019
EEC492/693/793 - iPhone Application Development
EEC492/693/793 - iPhone Application Development 2

3. EEC492/693/793 - iPhone Application Development
More on Table Views
UITableView Data Source
UITableView Delegate
UITableViewController
UITableViewCell
4/9/2019
EEC492/693/793 - iPhone Application Development

4. Basic UITableViewDataSource Methods
Provide number of sections and rows
// Optional method, defaults to 1 if not implemented
- (NSInteger)numberOfSectionsInTableView:(UITableView *)table;
// Required method
- (NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section;
Provide cells for table view as needed
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath;
4/9/2019
EEC492/693/793 - iPhone Application Development

5. Datasource Message Flow
numberOfSectionsInTableView:
How many
Sections?
Datasource 5
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EEC492/693/793 - iPhone Application Development

6. Datasource Message Flow
tableView:numberOfRowsInSection: 1
How many rows
In section 0?
Datasource
4/9/2019
EEC492/693/793 - iPhone Application Development

7. Datasource Message Flow
tableView:cellForRowAtIndexPath:
Cell with text
“John Appleseed”
What to display at
section 0, row 0?
Datasource
4/9/2019
EEC492/693/793 - iPhone Application Development

8. NSIndexPath and Table Views
Cell location described with an index path
Section index + row index
Category on NSIndexPath with helper methods
@interface NSIndexPath (UITableView)
+ (NSIndexPath *)indexPathForRow:(NSUInteger)row
inSection:(NSUInteger)section;
@property(nonatomic,readonly) NSUInteger section;
@property(nonatomic,readonly) NSUInteger row;
@end
4/9/2019
EEC492/693/793 - iPhone Application Development

9. Single Section Table View
Return the number of rows
- (NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section {
return [myStrings count]; }
Provide a cell when requested
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
UITableViewCell *cell = ...;
cell.textLabel.text = [myStrings objectAtIndex:indexPath.row]
return [cell autorelease];
4/9/2019
EEC492/693/793 - iPhone Application Development

10. EEC492/693/793 - iPhone Application Development
Cell Reuse
When asked for a cell, reuse one if possible
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView
if (cell == nil) {
cell = [[[UITableViewCell alloc]
initWithStyle:...
autorelease]; }
cell.text = [myStrings objectAtIndex:indexPath.row]
return cell;
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EEC492/693/793 - iPhone Application Development

11. EEC492/693/793 - iPhone Application Development
Triggering Updates
When is the datasource asked for its data?
When a row becomes visible
When an update is explicitly requested by calling -reloadData
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.tableView reloadData]; }
4/9/2019
EEC492/693/793 - iPhone Application Development

12. Section and Row Reloading (and Insertion and Deletion)
Section reloading
- (void)reloadSections:(NSIndexSet *)sections
withRowAnimation:(UITableViewRowAnimation)animation;
Row reloading
- (void)reloadRowsAtIndexPaths:(NSArray *)indexPaths
Insert/delete
- (void)insertSections:(NSIndexSet *)sections
- (void)deleteSections:(NSIndexSet *)sections
- (void)insertRowsAtIndexPaths:(NSArray *)indexPaths
- (void)deleteRowsAtIndexPaths:(NSArray *)indexPaths
4/9/2019
EEC492/693/793 - iPhone Application Development

13. Allow Editing and Reordering Cells
Enable editing:
Call self.tableView setEditing:YES
Or use the system provided editButtonItem
Allow deleting cells
Implement data source method:
- (void)tableView:(UITableView *)tableView
commitEditingStyle:(UITableViewCellEditingStyle)editingStyle
forRowAtIndexPath:(NSIndexPath *)indexPath {
NSUInteger row = [indexPath row];
[self.list removeObjectAtIndex:row];
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath]
withRowAnimation:UITableViewRowAnimationFade]; }
4/9/2019
EEC492/693/793 - iPhone Application Development

14. Allow Editing and Reordering Cells
Allow reordering cells
- (BOOL)tableView:(UITableView *)tableView
canMoveRowAtIndexPath:(NSIndexPath *)indexPath {
return YES; }
- (void)tableView:(UITableView *)tableView
moveRowAtIndexPath:(NSIndexPath *)fromIndexPath
toIndexPath:(NSIndexPath *)toIndexPath
// update data in the model accordingly …
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EEC492/693/793 - iPhone Application Development

15. Disallowing Editing/Reordering
Disallowing deleting
- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView
editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath {
return UITableViewCellEditingStyleNone; }
Disallowing reordering
- (BOOL)tableView:(UITableView *)tableView
canMoveRowAtIndexPath:(NSIndexPath *)indexPath
return NO;
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EEC492/693/793 - iPhone Application Development

16. UITableView Delegate: Controlling Table View Appearance & Behavior
Customize appearance of table view cell
- (void)tableView:(UITableView *)tableView
willDisplayCell:(UITableViewCell *)cell
forRowAtIndexPath:(NSIndexPath *)indexPath;
Validate and respond to selection changes
- (NSIndexPath *)tableView:(UITableView *)tableView
willSelectRowAtIndexPath:(NSIndexPath *)indexPath;
didSelectRowAtIndexPath:(NSIndexPath *)indexPath;
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EEC492/693/793 - iPhone Application Development

17. Responding to Selection
// For a navigation hierarchy...
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Get the row and the object it represents
NSUInteger row = indexPath.row
id objectToDisplay = [myObjects objectAtIndex:row];
// Create a new view controller and pass it along
MyViewController *myViewController = ...;
myViewController.object = objectToDisplay;
[self.navigationController
pushViewController:myViewController animated:YES]; }
4/9/2019
EEC492/693/793 - iPhone Application Development

18. Altering or Disabling Selection
- (NSIndexPath *)tableView:(UITableView *)tableView
willSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Don’t allow selecting certain rows?
if (indexPath.row == ...) {
return nil;
} else {
return indexPath; }
4/9/2019
EEC492/693/793 - iPhone Application Development

19. UITableViewController
Convenient starting point for view controller with a table view
Table view is automatically created
Controller is table view’s delegate and datasource
Takes care of some default behaviors
Calls -reloadData the first time it appears
Deselects rows when user navigates back
Flashes scroll indicators
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EEC492/693/793 - iPhone Application Development

20. EEC492/693/793 - iPhone Application Development
Table View Cells
Initializer
- (id)initWithStyle:(UITableViewCellStyle)style
reuseIdentifier:(NSString *)reuseIdentifier;
Cell Styles
UITableViewCellStyleDefault, UITableViewCellStyleSubtitle, UITableViewCellStyleValue1, UITableViewCellStyleValue2
Basic properties
UITableViewCell has an image view and one or two text labels
cell.imageView.image = [UIImage
cell.textLabel.text Idol”;
cell.detailTextLabel.text Idol”;
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EEC492/693/793 - iPhone Application Development

21. Table View Cell Accessory Types
// UITableView delegate method
- (UITableViewCellAccessoryType)tableView:(UITableView *)table
accessoryTypeForRowWithIndexPath:(NSIndexPath *)indexPath;
- (void)tableView:(UITableView *)tableView
accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath {
// Only for the blue disclosure button
NSUInteger row = indexPath.row;
... }
UITableViewCellAccessoryDisclosureIndicator
UITableViewCellAccessoryDetailDisclosureButton
UITableViewCellAccessoryCheckmark
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EEC492/693/793 - iPhone Application Development

22. Customizing the Content View
For cases where a simple image + text cell doesn’t suffice
UITableViewCell has a content view property
Add additional views to the content view
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = ...;
CGRect frame = cell.contentView.bounds;
UILabel *myLabel = [[UILabel alloc] initWithFrame:frame];
myLabel.text = ...;
[cell.contentView addSubview:myLabel];
[myLabel release]; }
4/9/2019
EEC492/693/793 - iPhone Application Development

23. Using Table View and Navigation Controller Together
Pushing a TableViewController as the first view controller on the navigation stack
- (void)applicationDidFinishLaunching:(UIApplication *)application {
UINavigationController *navController = [[UINavigationController alloc] init];
FirstLevelViewController *viewController = [[FirstLevelViewController alloc] init];
[navController pushViewController:viewController animated:NO];
[viewController release];
[window addSubview:navController.view];
[window makeKeyAndVisible]; }
Do Not Follow the Book on This Step
4/9/2019
EEC492/693/793 - iPhone Application Development

24. Push Another View Controller on the Stack due to User Actions
- (void)tableView:(UITableView *)tableView
accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath {
childController = [[DisclosureDetailController alloc]
bundle:nil]; …
[self.navigationController pushViewController:childController animated:YES]; }
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
PresidentDetailController *childController = [[PresidentDetailController alloc]
initWithStyle:UITableViewStyleGrouped]; ….
[self.navigationController pushViewController:childController animated:YES]; }
4/9/2019
EEC492/693/793 - iPhone Application Development

25. Pop a View Controller from the Stack
Tag the back button
When handling user action
-(IBAction)cancel:(id)sender{
[self.navigationController popViewControllerAnimated:YES]; }
4/9/2019
EEC492/693/793 - iPhone Application Development

26. EEC492/693/793 - iPhone Application Development
Assignment
Build the Nav app
Please use the better way to push the first table view controller on the stack
Challenge
In the current Nav app, the PresentsView is NOT updated after you have modified a President’s info (in the PresidentDetail view)
Fix this!
4/9/2019
EEC492/693/793 - iPhone Application Development