Ways to add new view to current view

There are at least 3 ways to add a new view to the current view:

1. addSubView
2. pushViewController
3. presentModalViewController

Below are some comparisons between the above methods:

Feature	addSubView  / insertSubView	pushViewController	presentModalViewController
Usage	It is typically use to create view heirarchy programmatically. A view heirarchy will consist of multiple subviews that make up different components in the view. Each sub view will has its own draw and animation handling. Each sub view also has its own event handling. Alternatively, view heirarchy can be created using Interface Builder.	In many IPhone application, the user will need to go through different pages of form / view to complete a specific workflow for a task. Typically, pushViewController is used to step the user through the different pages to complete the task. It is usually work with navigation controller. Push view controller will create the visual effect of push page left to right.	In some IPhone application, while performing a task, the user will need to complete a self-contained subtask before he can continue the task. Modal view mechanism can be used to accomplish the subtask function. By default, the present modal viewController will slide a set of controls from bottom to top to the current view. The modal view need to be dismissed before the user can continue with the current view.
Compatibility with navigationController tabBarController	Usually the subview will be added to the top of the current view, hence cover the navigation bar. The toolbar may also be covered depending on  the size of the subview. The subview can use setFrame to position it below the navigation controller. Eg: [self.view setFrame:CGRectMake(0,60,320,400)];	Work well with tabBarController, navigationController	Both controllers will be hidden from the modal view. Except for partialCurl transitionStyle. which the NavigationBar will still be visible.
Return back from the added view	Has to implement return mechanism.	Can have automatic back button created if the root Controller is navigation controller and the back barButtonItem is created in the root navigation controller. ** For default back button to work, each view must has title setted.	Has to implement return mechanism.
Sample code: Add newViewController	[self.viewController.view addSubView: newViewController.view];	[self.viewController pushViewController: newViewController];	[self.viewController presentModalViewController: newViewController];
Sample code: Remove newViewController	[self.view removeFromSuperView];	[self.viewController popViewController Animated: YES];	[self dismissModalViewController Animated: YES];

Creating Modal View

In a typical Windows environment, modal window is a child or popup window where user can not press on any control on the parent window before complete and close the child or popup modal window.

For IPhone or IPad application, modal view behave the same. Sometime it is neccessary to popup a modal view to the user for data entry or other action view which the user has to complete the data entry view before the user can proceed to other part of the application.

The following steps outline how such modal view can be acheived:

1. Create a UIViewController subclass, by New File -> Cocoa   touch -> UIViewController subclass.

    Ensure that the "With XIB for user interface" option is selected.

    eg.  create a UIViewController subclass -> ModalController

2. Use interface builder to create the needed UI in the created ModalController.

3. Add the following modal view invocation code in the appropiate section:

ModalController* modal = [[ModalController alloc] initWithNibName:Nil bundle:Nil];

[modal setModalTransitionStyle:UIModalTransitionStylePartialCurl];  // this will determine how the modal transition in

[modal setModalPresentationStyle:UIModalPresentationFullScreen];  // this will how the modal will be presented

[self.navigationController presentModalViewController:modal animated:YES];

4. Add the following modal view removal code in the appropiate section, eg. link to the exit button of the ModalController:

- (IBAction) backToMain: (id) sender {

    [self dismissModalViewControllerAnimated:YES];

}

Creating application without status bar

The status bar in an iphone application shows the network connections (Telco, WIFI, bluetooth.. etc), date, battery usage, location icon... etc.

For some application, it may be usefull to hide the status bar so that the application has maximum screen area.

To hide the status bar, send the setStatusBarHidden message to the UIApplication object. It should be send in the UIApplication's didFinishLaunchingWithOptions method. This method will be invoked when the application finish launching.

eg.

   - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)

      launchOptions  {
            ..... 

            [[UIApplication sharedApplication]setStatusBarHidden:YES];
            .......
   }

Creating UITableView

The following steps show how to create UITableView in a iPhone application, it is very similar to the UIPickerView implementation:
1. Create the UITableView in interface builder.

2. Add the IBOutlet for UITableView in the interface (.h) file. (optional, if the UITableView is needed to reference in the code)

3. Link the IBOutlet for UITableView to the UITableView in interface builder. (optional, only if the IBOutlet is created in step2)

4. Implement the following datasource and delegate methods for basic browsing function:

    a.  numberOfRowsInSection datasource method should return the number of row in the table.

        eg.

    - (NSInteger)tableView:(UITableView *) tableView numberOfRowsInSection: (NSInteger)section {

          return [array count];

    }

    b.  cellForRowAtIndexPath datasource method should return a table cell for the row at the indexPath for the table.

        eg.

        - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:
          (NSIndexPath *)indexPath {

               UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];    }

               if (cell==NULL) {

                  cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:@"Cell"]
                            autorelease];

              }

             cell.text= [array objectAtIndex:indexPath.row];          // cell.text is deprecated

            return cell;

    }

    c. numberOfSectionsInTableView datasource method should return the number of sections in the UItableView.   

      (Optional, only for multiple section UITableView)

       eg.

          - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

             return numberOfSections;

         }

    d. titleForHeaderInSection datasource method should return the header of the section.

       (Optional, only needed for multiple sections UITableView)

       eg.

       - (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {

           if (section == 0)   return @"section 1";

           else if (section ==1)   return @"section 2";

           // more code to return header ......

       }

     e. didSelectRowAtIndexPath delegate method would be called if the user selected a row in the UITableView.

        (Optional, only needed if there are actions to be performed when user selected a row)

        eg.

       - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

           // actions to be performed...

           // indexPath.section will give the selected section

           // indexPath.row will give the selected row

           // can implement show detail view....

       }

       f. accessoryTypeForRow delegate method should return the type of accessory (like button, arrow...).

       (Optional, only needed if button or arrow accessory is needed to display at the side)

       eg.

       - (UITableViewCellAccessoryType)tableView:(UITableView *)tableView
          accessoryTypeForRowWithIndexPath:(NSIndexPath *)indexPath {

                //return UITableViewCellAccessoryDetailDisclosureButton;  

               //return UITableViewCellAccessoryDisclosureIndicator;

               
               //return UITableViewCellAccessoryNone;

                //return UITableViewCellAccessoryCheckmark;  

       }

       g. accessoryButtonTappedForRowWithIndexPath delegate method would be invoked when the user clicked on the accessoryButton.
      (Optional, only needed if button in step f is setted)
        eg.

          - (void)tableView:(UITableView *)tableView accessoryButtonTappedForRowWithIndexPath:
            (NSIndexPath *)indexPath {
                 // invoke a method here
                 // eg. [self tableView:tableView didSelectRowAtIndexPath:indexPath];
          }

5. The following steps describe how to implement delete function for UITableView:
    a. Set the tableView into editing mode. There are two ways to set a tableView into editing mode:
        i. tableView.editing property set to YES
        eg.

            tableView.editing = YES;
            // or [tableView setEditing:YES animated:YES]

        ii. If the tableView has implmented with UINavigationController, set the navigationBarButton (left or right) to editButtonItem. This will allow toggle the tableView into editing mode.
        eg.

           self.navigationItem.rightBarButtonItem = self.editButtonItem;

     b. Implement the commitEditingStyle datasource method. This method will be invoked, when a tableView item is deleted.
       eg.

           - (void)tableView:(UITableView *)tableView commitEditingStyle:
             (UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
               if (editingStyle == UITableViewCellEditingStyleDelete) { 
                        // ... delete code here ....               
                }
           }

6. Link the UITableView's datasource and delegate to the code that implement the above datasource and   
    delegate methods.

7. The tableView can be set with different background color using the setBackgroundColor method.
     Eg.

[self.tableView setBackgroundColor:[UIColor groupTableViewBackgroundColor]];