Wednesday, February 22, 2012

The Art to Make Your iPhone App Shine!

This is not a coding tutorial, but nonetheless very important aspect of iPhone app design.

There is a lot more to making an iPhone app than just making a software that functions. For your app to shine, you need to consider a few features that are essential to a good app. As an app developer, you need to think differently than a software developer. An app developer develops and create software that has the nearest human interactions to a user. Our aim, should be, therefore to make a an app that simulates a pet. A pet owner loves his pet, caresses it, loves it, brings it to the bed. That's what you should aim your app should be, and in order to create something like that, consider the following:

1. Sound effects. Many apps out there do not really need sound effects. But sound effects add interaction values to the users. For example, take the Twitter app, it does not NEED sound, but it has some sound like when you drag down the list to update. (It emulates a pet barking or meowing to the owner)

2. Gestures. Do not rely 100% on button taps if you can. Use gestures - pinch, swipe, drag, shake, turn, twirl. (These actions relate to caressing a pet).

3. Help information. Many apps do not have this. Even when they have it, it is too obscured on how to get it. Help info includes how to use the app, explanation of how to use a certain feature that is not so obvious, and so on. Sure, you wrote about it in the app description, but when the user is done downloading your app, do you really expect him/her to return to your app page? No!

4. Animations. Spend a little time to code nice animations. Don't just make things appear out of nowhere. Make it SLIDE, make it FADE, make it DISSOLVE, etc. (These relates to a pet doing tricks for the owner).

5. Polished Graphics. Would you buy an ugly dog or cat as a pet. There you go. Firstly, Apple and Superb Graphics rhymes. So, polish your graphics again, and again, and again. 

Well, that's 5 very important aspect of iPhone design. Remember them when you are designing an iPhone app. Good luck.

Tuesday, February 14, 2012

How To: Find for a Function/Method That You Did Not Know Existed?

This is a simple but VERY USEFUL tip for new developers who often want to know what other function is available for a particular object. The hard way is to go through Apple's Documentation and read for each Objects.

The easy way is through your XCode code editor. Let me show you how:

Say, you are wondering (or forgetting and trying to remember) what was the code to write variable into the NSUserDefaults (sandbox of your app).

Normally, XCode 4 will automatically pop up the code completion, but if it is not, then you can press ESC button on your keyboard and it will pop it up for you.

Once this is popped up, you can scroll through the valid functions that starts with "set" because we typed that already.

Even if you haven't type anything, just go ahead and press ESC and all possible functions to be input at the cursor point will be popped up for you. 

But surely, the options listed are a whole lot more to choose from. It is a very helpful feature of XCode which every devs should know.

Tuesday, February 7, 2012

How To: Create Horizontal UIPickerView (Custom)

It's been a while since I last wrote any real tutorial. I wanted to write this tutorial for a while, but was delayed due to updating my own apps, and creating new apps, and also due to relatives who got seriously ill, yadda yadaa, whoop dee doo whoop dee dye and so forth.

Anyway, today I'd like to show you how you can create a custom sized horizontal UIPickerView. UIPickerView is an awesome object to display a list of items. While you can accomplish this using UIScrollView easily, the behaviour of UIPickerView is slightly better because the items in UIPickerView is auto selected when user chooses it - that cool spring effect centers the selection nicely at as well.

So lets get started, first of all, all you need to do is drop a UIPickerView object on your view in the Interface Builder. Then in your .h file input:

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <UIPickerViewDelegate> {

    IBOutlet UIPickerView *pickerView;

    NSMutableArray *itemArray;


@property (nonatomic, retain)  UIPickerView *pickerView;


Basically we're just declaring our UIPickerView as IBOutlet (nothing new in declaration method here). We also added a NSMutableArray so that we can manipulate our items and be able to add our items in the pickerview easily later. We also add UIPickerViewDelegate at the interface because we will be using the built in Delegate functions of UIPickerView object.

Hang on a minute, what the heck is an NSMutableArray? If you are familiar with some basic programming I am sure that you are familiar with an array. An array is a defined quantity of collection of data. For eg:

myFish[14] holds 15 variables. from 0 to 14. (Remember index of an arrays always start with 0).
So you can access them by myFish[0] = Tetras; myFish[1] = Rasboras. And so on. But you are limited to 15 fishes. This is where NSMutableArray differs, an NSMutableArray is an array that is mutable, or expandable/changeable. So if you declare myFish as an NSMutableArray, then you can have up to whatever value you wish, so long as you be careful not to overload it (memory issues).

Back to the tutorial:

So now you have declared the UIPickerView, go to Interface Builder and connect BOTH the "delegate" and "Referencing Outlet" to the FileOwner.

Next, we go to .m file and synthesize the UIPickerView. Also we'd want to add the UIPickerView delegate methods as below (read the comments for each delegate's purposes:

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)thePickerView {

return 1;


- (NSInteger)pickerView:(UIPickerView *)thePickerView numberOfRowsInComponent:(NSInteger)component {

return [itemArray count];


- (UIView *)pickerView:(UIPickerView *)thePickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view


return [itemArray objectAtIndex: row];


- (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {


This delegate is easy to implement, just type "return #;" where # is the number of components
you want. "Component" is the scrollable object in a pickerview. For example, a date pickerview has 3 components where user can select each of date, month and year. For our case, we are going to use just 1 component.

This delegate you need to return the number of items in each component. If you have multiple components,
you need to use switch (or if) statement to specify for each components. In our case we just have 1 component, so we only return the item count of our array.

This delegate is where you specify the "VIEW"/"Object" of the item. Since we store our items in
array, we just need to return the object by using: [itemArray objectAtIndex:row];

This delegate is always called when user selects an item. Write the actions you'd like to happen when user select something in here.

Remember that delegate functions must be written as it is, EXACTLY. Any deviation might cause it not to work. Do check Apple docs for the latest delegate function names in case your implementation does not work.

Next is the fun part, customizing the UIPickerView. We will add the customization code in the viewDidLoad as we want it to be customized after the view is loaded. Write the codes below in the viewDidLoad.

// set the pickerview delegate to itself. This is important because if you don't set

// this, then the delegate functions will not work/be called.

 self.pickerView.delegate = self;

// here is where the customization lies: CGAffineTransform is a way to transform

// object according to scale and rotation. Here we rotate the pickerview by PI/2

// which is 90 degrees in radians. Then we concat the rotation transform with

// scale transform, and finally setting the pickerview transform.

CGAffineTransform rotate = CGAffineTransformMakeRotation(3.14/2);

 rotate = CGAffineTransformScale(rotate, 0.1, 0.8);

 [self.pickerView setTransform:rotate]; 

// set the center location. = CGPointMake(160,75);

  // Here I decided to add UILabel as the item's "object"

// you can use ANYTHING here, like UIImageViews or any class of UIView

// Since we rotate the pickerview in one direction, we need to compensate

// the item's angle by counter rotating it in the opposite direction,

// and adjust the scale as well. You may need to try a few times to get

// the right/suitable size as for the scale.

 UILabel *theview[20];

 CGAffineTransform rotateItem = CGAffineTransformMakeRotation(-3.14/2);

 rotateItem = CGAffineTransformScale(rotateItem, 1, 10);

 // next alloc and create the views in a loop. here I decided to have 20

// UIlabels, each with a text of 1 to 20. Set the other UIlabel's property as you wish.

 for (int i=1;i<=20;i++) { 

  theview[i] = [[UILabel alloc] init];

  theview[i].text = [NSString stringWithFormat:@"%d",i];

  theview[i].textColor = [UIColor blackColor];

  theview[i].frame = CGRectMake(0,0, 100, 100);

  theview[i].backgroundColor = [UIColor clearColor];

  theview[i].textAlignment = UITextAlignmentCenter;

  theview[i].shadowColor = [UIColor whiteColor];

  theview[i].shadowOffset = CGSizeMake(-1,-1);

  theview[i].adjustsFontSizeToFitWidth = YES;

    UIFont *myFont = [UIFont fontWithName:@"Georgia" size:15];

  [theview[i] setFont:myFont];

    theview[i].transform = rotateItem;



    // then we initialize and create our NSMutableArray, and add all 20 UIlabel views

// that we just created above into the array using "addObject" method.

   itemArray = [[NSMutableArray alloc] init];

  for (int j=1;j<=20;j++) {


        [itemArray addObject:theview[j]];


That is all there is to it. Run your app and it should display a nice horizontal UIPickerView!
How about have it do something when you select an item? Easy. Go back to .h and add another IBOutlet of UILabel *myLabel. Go to your XIB file in IB and add a label and connect the Outlet to FileOwner as myLabel. Goto .m file and synthesize myLabel. Then goto UIPickerView delegate called didSelectRow and add the following line:
myLabel.text = [NSString stringWithFormat:@"SELECTED: %d", row+1];
Now when you select a row, the label will show you which row you selected. Cool eh?
Well, that's it for now. Hope this tutorial helped someone. Good luck!