Naviga&on and Tab Bar Controllers and Table View

Transcription

1 Naviga&on and Tab Bar Controllers and Table View

2 UINaviga)onController Stack of view controllers Naviga)on bar

3 How It Fits Together Top view controller s view Top view controller s )tle Previous view controller s )tle Top view controller s toolbar items (iphone OS 3.0)

4 The views of a naviga)on interface

5 Objects managed by the naviga)on controller

6 The naviga)on stack

7 Loading Your Naviga&on Interface from a Nib File

8 Crea)ng a Naviga)on Controller Programma)cally - (void)applica)ondidfinishlaunching:(uiapplica)on *)applica)on{ UIViewController *rootcontroller = [[MyRootViewController alloc] init]; naviga)oncontroller = [[UINaviga)onController alloc] initwithrootviewcontroller:rootcontroller]; [rootcontroller release]; window = [[UIWindow alloc] initwithframe:[[uiscreen mainscreen] bounds]]; [window addsubview:naviga)oncontroller.view]; [window makekeyandvisible];}

9 Modifying the Naviga)on Stack Push to add a view controller - (void)pushviewcontroller:(uiviewcontroller *)viewcontroller animated:(bool)animated; Pop to remove a view controller - (UIViewController *)popviewcontrolleranimated:(bool)animated; Set to change the en&re stack of view controllers (iphone OS 3.0) - (void)setviewcontrollers:(nsarray *)viewcontrollers animated:(bool)animated;

10 Pushing Your First View Controller - (void)applica)ondidfinishlaunching { // Create a naviga)on controller navcontroller = [[UINaviga)onController alloc] init]; // Push the first view controller on the stack [navcontroller pushviewcontroller:firstviewcontroller animated:no]; // Add the naviga)on controller s view to the window [window addsubview:navcontroller.view]; }

11 In Response to User Ac)ons Push from within a view controller on the stack - (void)someac)on:(id)sender { // Poten)ally create another view controller UIViewController *viewcontroller =...; [self.naviga)oncontroller pushviewcontroller:viewcontroller animated:yes]; } Almost never call pop directly! Automa)cally invoked by the back bu_on

12 Messages sent during stack changes

13

14 A Controller for Each Screen

15 Connec)ng View Controllers Mul)ple view controllers may need to share data One may need to know about what another is doing Watch for added, removed or edited data Other interes)ng events

16 How Not To Share Data Global variables or singletons This includes your applica&on delegate! Direct dependencies make your code less reusable And more difficult to debug & test

17 Best Prac)ces for Data Flow Figure out exactly what needs to be communicated Define input parameters for your view controller For communica)ng back up the hierarchy, use loose coupling Define a generic interface for observers (like delega)on)

18 Customizing Naviga)on Bu_ons or custom controls Interact with the en)re screen

19 Naviga)on bar styles

20 The objects associated with a naviga)on bar

21 UINaviga)onItem Describes appearance of the naviga)on bar Title string or custom )tle view Lee & right bar bu_ons More proper)es defined in UINaviga)onBar.h Every view controller has a naviga&on item for customizing Displayed when view controller is on top of the stack

22 Naviga)on Item Ownership

23 The objects associated with a naviga)on bar

24 Displaying a Title UIViewController already has a )tle NSString *)tle; Naviga)on item inherits automa)cally Previous view controller s )tle is displayed in back bu_on viewcontroller.)tle Detail ;

25 Lee & Right Bu_ons UIBarBu_onItem Special object, defines appearance & behavior for items in naviga)on bars and toolbars Display a string, image or predefined system item Target + ac)on (like a regular bu_on)

26 Text Bar Bu_on Item - (void)viewdidload { UIBarBu_onItem *foobu_on = [[UIBarBu_onItem alloc] initwithtitle:@"foo style:uibarbu_onitemstylebordered target:self ac)on:@selector(foo:)]; self.naviga)onitem.leebarbu_onitem = foobu_on; } [foobu_on release];

27 System Bar Bu_on Item - (void)viewdidload { UIBarBu_onItem *addbu_on = [[UIBarBu_onItem alloc] initwithbarbu_onsystemitem:uibarbu_onsystemitemadd style:uibarbu_onitemstylebordered target:self ac)on:@selector(add:)]; self.naviga)onitem.rightbarbu_onitem = addbu_on; [addbu_on release]; }

28 Edit/Done Bu_on Very common pa_ern Every view controller has one available Target/ac)on already set up self.naviga)onitem.leebarbu_onitem = self.editbu_onitem; // Called when the user toggles the edit/done bu_on - (void)setedi)ng:(bool)edi)ng animated:(bool)animated { // Update appearance of views }

29 Custom Title View Arbitrary view in place of the )tle UISegmentedControl *segmentedcontrol =... self.naviga)onitem.)tleview = segmentedcontrol; [segmentedcontrol release];

30 Back Bu_on Some)mes a shorter back bu_on is needed self.)tle Hello there, CS193P! ; UIBarBu_onItem *heybu_on = [[UIBarBu_onItem alloc] initwithtitle:@ Hey!...]; self.naviga)onitem.backbu_onitem = heybu_on; [heybu_on release];

31 // View 3 - Custom right bar bu_on with a view UISegmentedControl *segmentedcontrol = [[UISegmentedControl alloc] initwithitems: [NSArray arraywithobjects: [UIImage imagenamed:@"up.png"], [UIImage imagenamed:@"down.png"], nil]]; [segmentedcontrol addtarget:self ac)on:@selector(segmentac)on:) forcontrolevents:uicontroleventvaluechanged]; segmentedcontrol.frame = CGRectMake(0, 0, 90, kcustombu_onheight); segmentedcontrol.segmentedcontrolstyle = UISegmentedControlStyleBar;segmentedControl.momentary = YES; defaulttintcolor = [segmentedcontrol.)ntcolor retain]; // keep track of this for later UIBarBu_onItem *segmentbaritem = [[UIBarBu_onItem alloc] initwithcustomview:segmentedcontrol]; [segmentedcontrol release]; self.naviga)onitem.rightbarbu_onitem = segmentbaritem; [segmentbaritem release];

32 Toolbar items in a naviga)on interface

33 (void)configuretoolbaritems { UIBarBu_onItem *flexiblespacebu_onitem = [[UIBarBu_onItem alloc] initwithbarbu_onsystemitem:uibarbu_onsystem ItemFlexibleSpace target:nil ac)on:nil]; // Create and configure the segmented control UISegmentedControl *sorttoggle = [[UISegmentedControl alloc] initwithitems:[nsarray nil]]; sorttoggle.segmentedcontrolstyle = UISegmentedControlStyleBar; sorttoggle.selectedsegmentindex = 0; [sorttoggle addtarget:self ac)on:@selector (togglesor)ng:) forcontrolevents:uicontroleventvaluechanged]; // Create the bar button item for the segmented control UIBarButtonItem *sorttogglebuttonitem = [[UIBarButtonItem alloc] initwithcustomview:sorttoggle]; [sorttoggle release]; } // Set our toolbar items self.toolbaritems = [NSArray arraywithobjects: flexiblespacebuttonitem, sorttogglebuttonitem, flexiblespacebuttonitem, nil]; [sorttogglebuttonitem release]; [flexiblespacebuttonitem release];

34 UITabBarController Array of view controllers Tab bar

35 How It Fits Together Selected view controller s view All view controllers )tles

36 The views of a tab bar interface

37 A tab bar controller and its associated view controllers

38 Tab bar items of the ipod applica)on

39 Nib file containing a tab bar interface

40 Seong Up a Tab Bar Controller - (void)applica)ondidfinishlaunching // Create a tab bar controller tabbarcontroller = [[UITabBarController alloc] init]; // Set the array of view controllers tabbarcontroller.viewcontrollers = myviewcontrollers; } // Add the tab bar controller s view to the window [window addsubview:tabbarcontroller.view];

41 Tab Bar Appearance View controllers can define their appearance in the tab bar UITabBarItem Title + image or system item Each view controller comes with a tab bar item for customizing

42 Crea)ng Tab Bar Items Title and image - (void)viewdidload { UITabBarItem *item = [[UITabBarItem alloc] initwithtitle:@ Playlists image:[uiimage imagenamed:@ music.png ] tag:0]; self.tabbaritem = item; [item release]; }

43 Crea)ng Tab Bar Items System item - (void)viewdidload { UITabBarItem *item = [[UITabBarItem alloc] initwithtabbarsystemitem: UITabBarSystemItemBookmarks tag:0] self.tabbaritem = item; [item release]; }

44 Crea)ng the view controller s tab bar item - (id)init { if (self = [super initwithnibname:@"myviewcontroller" bundle:nil]) { self.)tle View Controller ; UIImage* animage = [UIImage imagenamed:@"myviewcontrollerimage.png"]; UITabBarItem* theitem = [[UITabBarItem alloc] initwithtitle:@"home" image:animage tag:0]; self.tabbaritem = theitem; } } [theitem release]; return self;

45 Removing the current tab - (IBAc)on)processUserInforma)on:(id)sender{ // Call some app- specific method to validate the user data. } // If the custom method returns YES, remove the tab. if ([self userdataisvalid]) { NSMutableArray* newarray = [NSMutableArray arraywitharray:self.tabbarcontroller.viewcontrollers]; [newarray removeobject:self]; [self.tabbarcontroller setviewcontrollers:newarray animated:yes]; }

46 Preven)ng the selec)on of tabs - (BOOL)tabBarController:(UITabBarController *)atabbar shouldselectviewcontroller:(uiviewcontroller *)viewcontroller { if (![self hasvalidlogin] && (viewcontroller!= [atabbar.viewcontrollers objectatindex:0]) ) { // Disable all but the first tab. return NO; } return YES; }

47 More View Controllers

48 Tab Bar + Naviga)on Controllers Mul)ple parallel hierarchies

49 Tab Bar + Naviga)on Controllers

50 Nes)ng Naviga)on Controllers Create a tab bar controller tabbarcontroller = [[UITabBarController alloc] init]; Create each naviga)on controller navcontroller = [[UINaviga)onController alloc] init]; [navcontroller pushviewcontroller:firstviewcontroller animated:no]; Add them to the tab bar controller tabbarcontroller.viewcontrollers = [NSArray arraywithobjects: navcontroller, anothernavcontroller, someviewcontroller, nil];

51 Table Views Display lists of content Single column, mul)ple rows Ver)cal scrolling Large data sets Powerful and ubiquitous in iphone applica)ons

52 Table View Styles UITableViewStylePlain UITableViewStyleGrouped

53 Table View Anatomy Plain Style Table Header Section Header Table Cell Section Footer Section Table Footer

54 Table View Anatomy Grouped Style Table Header Section Header Table Cell Section Footer Section Table Footer

55 Header and footer of a sec)on

56 UITabelView Declaring methods that allow you to configure the appearance of the table view specifying the default height of rows or providing a view used as the header for the table access to the currently selected row as well as specific rows or cells manage selec)ons, scroll the table view, and insert or delete rows and sec)ons. UITableView inherits from UIScrollView, which defines scrolling behavior for views with content larger than the size of the window. UITableView redefines the scrolling behavior to allow ver)cal scrolling only.

57 Using Table Views Displaying your data in the table view Customizing appearance & behavior

58 Displaying Data in a Table View

59 A Naïve Solution Table views display a list of data, so use an array [mytableview setlist:mylistofstuff]; Issues with this approach All data is loaded upfront All data stays in memory

60 A More Flexible Solution Another object provides data to the table view Not all at once Just as it s needed for display Like a delegate, but purely data-oriented

61 Calling sequence for crea)ng and configuring a table view

62 UITableViewDataSource 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 // Required method - (UITableViewCell *)tableview:(uitableview *)tableview cellforrowatindexpath:(nsindexpath *)indexpath;

63 Datasource Message Flow numberofsectionsintableview: tableview:numberofrowsinsec)on: tableview:cellforrowatindexpath:

64 NSIndexPath Generic class in Foundation Path to a specific node in a tree of nested arrays

65 NSIndexPath and Table Views Cell location described with an index path Section index + row index Category on NSIndexPath with helper NSIndexPath (UITableView) + (NSIndexPath *)indexpathforrow:(nsuinteger)row NSUInteger NSUInteger

66 Crea&ng a Table View RootViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> { NSArray *timezonenames; (nonatomic, retain) NSArray - (void)loadview { UITableView *tableview = [[UITableView alloc] initwithframe:[[uiscreen mainscreen] applicationframe] style:uitableviewstyleplain]; tableview.autoresizingmask = UIViewAutoresizingFlexibleHeight UIViewAutoresizingFlexibleWidth; } tableview.delegate = self; tableview.datasource = self; [tableview reloaddata]; self.view = tableview; [tableview release];

67 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]; }

68 Cell Reuse When asked for a cell, it would be expensive to create a new cell each time. - (UITableViewCell *)dequeuereusablecellwithidentifier: *)tableview:(uitableview *)tableview (NSString cellforrowatindexpath:(nsindexpath *)identifier; *)indexpath { UITableViewCell *cell = [tableview dequeuereusablecellwithidentifier:@ MyIdentifier ]; if (cell == nil) { cell = [[[UITableViewCell alloc] initwithstyle:... reuseidentifier:@ MyIdenifier ] autorelease]; } cell.text = [mystrings objectatindex:indexpath.row] } return cell;

69 - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableview { return [regions count]; } - (NSInteger)tableView:(UITableView *)tableview numberofrowsinsection:(nsinteger)section { // Number of rows is the number of time zones in the region for the specified section. Region *region = [regions objectatindex:section]; return [region.timezonewrappers count]; } - (NSString *)tableview:(uitableview *)tableview titleforheaderinsection:(nsinteger)section { // The header for the section is the region name -- get this from the region at the section index. Region *region = [regions objectatindex:section]; return [region name]; } - (UITableViewCell *)tableview:(uitableview *)tableview cellforrowatindexpath:(nsindexpath *)indexpath { static NSString *MyIdentifier ; UITableViewCell *cell = [tableview dequeuereusablecellwithidentifier:myidentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initwithstyle:uitableviewcellstyledefault reuseidentifier:myidentifier] autorelease]; } Region *region = [regions objectatindex:indexpath.section]; TimeZoneWrapper *timezonewrapper = [region.timezonewrappers objectatindex:indexpath.row]; cell.textlabel.text = timezonewrapper.localename; return cell; }

70 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];

71 Section and Row Reloading - (void)insertsections:(nsindexset *)sections withrowanimation:(uitableviewrowanimation)animation; - (void)deletesections:(nsindexset *)sections withrowanimation:(uitableviewrowanimation)animation; - (void)reloadsections:(nsindexset *)sections withrowanimation:(uitableviewrowanimation)animation; - (void)insertrowsatindexpaths:(nsarray *)indexpaths withrowanimation:(uitableviewrowanimation)animation; - (void)deleterowsatindexpaths:(nsarray *)indexpaths withrowanimation:(uitableviewrowanimation)animation; - (void)reloadrowsatindexpaths:(nsarray *)indexpaths withrowanimation:(uitableviewrowanimation)animation;

72 Calling sequence for inser)ng or dele)ng rows in a table view

73 Mapping levels of the data model to table views

74 Additional Datasource Methods Titles for section headers and footers Allow editing and reordering cells

75 Appearance & Behavior

76 UITableView Delegate Customize appearance and behavior Keep application logic separate from view Often the same object as datasource

77 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; - (void)tableview:(uitableview *)tableview didselectrowatindexpath:(nsindexpath *)indexpath;

78 Row Selection in Table Views In iphone applications, rows rarely stay selected Selecting a row usually triggers an event

79 Persistent Selection

80 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];

81 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; } }

82 UITableViewController

83 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

84 Table View Cells

85 Designated Initializer - (id)initwithframe:(cgrect)frame reuseiden)fier:(nsstring *)reuseiden)fier; DEPRECATED - (id)initwithstyle:(uitableviewcellstyle)style reuseidentifier:(nsstring *)reuseidentifier;

86 Cell Styles UITableViewCellStyleDefault UITableViewCellStyleSubtitle UITableViewCellStyleValue1 UITableViewCellStyleValue2

87 Basic properties UITableViewCell has an image view and one or two text labels cell.imageview.image = [UIImage imagenamed:@ vitolidol.png ]; cell.textlabel.text Vitol Idol ; cell.detailtextlabel.text Billy Idol ;

88 Accessory Types // UITableView delegate method - (UITableViewCellAccessoryType)tableView:(UITableView *)table accessorytypeforrowwithindexpath:(nsindexpath *)indexpath; UITableViewCellAccessoryDisclosureIndicator UITableViewCellAccessoryDetailDisclosureButton UITableViewCellAccessoryCheckmark - (void)tableview:(uitableview *)tableview accessorybuttontappedforrowwithindexpath:(nsindexpath *)indexpath { // Only for the blue disclosure button NSUInteger row = indexpath.row;... }

89 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];

90 Ques)ons?