iPhone Coding Tutorial – Inserting A UITextField In A UIAlertView

This will be a simple tutorial showing you how to put a UITextField in a UIAlertView. This is simple and just a couple lines if code. You will learn CGAffineTransform and coding UITextField programmatically.
Heres a screenshots of what we should get.

So lets go ahead and get started…
1. Create A New View Based Application
You can name it whatever you want, I am gonna name it TextFieldInAlert.

2. Implementing The Code
Jump in the viewcontroller.m or if you called it TextFieldInAlert then TextFieldInAlert.m Now find the -(void)viewDidLoad method. Uncomment it and put this code in there.

- (void)viewDidLoad {

[super viewDidLoad];

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@”Enter Name Here” message:@”this gets covered!”

delegate:self cancelButtonTitle:@”Dismiss” otherButtonTitles:@”OK!”, nil];

UITextField *myTextField = [[UITextField alloc] initWithFrame:CGRectMake(12, 45, 260, 25)];

[myTextField setBackgroundColor:[UIColor whiteColor]];

[alert addSubview:myTextField];

[alert show];

[alert release];

[myTextField release];

}

So we are basically calling a UIAlertView and then we are adding the UITextField programmatically. You might have noticed in the message part of the UIAlertView we put “this gets covered!”, if we didn’t put that sentence then the alerts buttons would go up more and the UITextField will be messed. You can try taking that line out and see what happens. Now Build and Run the app. Now you got the UITextField to be inside the UIAlertView. Now try tapping the UITextField. Uh oh, why is the Keyboard covering the UIAlertView? Well there is just a simple fix to this. We just add two more lines of code and it will fix that. Add this to your code

CGAffineTransform myTransform = CGAffineTransformMakeTranslation(0, 60);

[alert setTransform:myTransform];

So now your full code should be looking like this.

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@”Enter Name Here” message:@”this gets covered!” delegate:self cancelButtonTitle:@”Dismiss” otherButtonTitles:@”OK!”, nil];

UITextField *myTextField = [[UITextField alloc] initWithFrame:CGRectMake(12, 45, 260, 25)];

CGAffineTransform myTransform = CGAffineTransformMakeTranslation(0, 60);

[alert setTransform:myTransform];

[myTextField setBackgroundColor:[UIColor whiteColor]];

[alert addSubview:myTextField];

[alert show];

[alert release];

[myTextField release];

Now if you Build and Run, you will notice the UITextField is a little higher and when you tap the UITextField the Keyboard doesn’t cover it up anymore. That is what the CGAffineTransform was for. So that is basically it! There is a video tutorial also available and if you like video tutorial more then written ones you can check it out out by clicking HERE. You can download the source code below. Happy iCoding!
iPhone Tutorial – UITextField In A UIAlertView

MPMediaItemCollection Category

I'm currently working on the chapter for More iPhone 3 Development on accessing the iPod Library. I thought I'd throw out another bit of teaser code in the form of a category. MPMediaItemCollection is the class that is used to specify queues of songs to be played. Unfortunately, it's an immutable collection object, and there is no mutable counterpart to it. That makes it kind of a pain when you have to add, delete, or insert items into a collection, or when you want to join multiple collections together.

This category adds a bunch of methods to MPMediaItemCollection that make it easier to manipulate play queues. It doesn't make MPMediaItemCollection mutable, but it does the next best thing. It makes it easier to create new collections based on existing collections. There are methods that create new collections by inserting or deleting songs from an existing collection.

I plan to add a few additional methods for sorting and re-ordering collections for the final version of this category, so look for an update to this in the next few days.

Note: I fixed a couple of leaks after the initial posting

MPMediaItemCollection-Utils.h

#import <Foundation/Foundation.h>
#import <MediaPlayer/MediaPlayer.h>

@interface MPMediaItemCollection(Utils)
/** Returns the first media item in the collection
**/
- (MPMediaItem *)firstMediaItem;

/** Returns the last media item in the collection
**/
- (MPMediaItem *)lastMediaItem;

/** This method will return the item in this media collection at a specific index
**/
- (MPMediaItem *)mediaItemAtIndex:(NSUInteger)index;

/** Given a particular media item, this method will return the next media item in the collection.
If there are multiple copies of the same media item in the list, it will return the one
after the first occurrence.
**/
- (MPMediaItem *)mediaItemAfterItem:(MPMediaItem *)compare;

/** Returns the title of the media item at a given index.
**/
- (NSString *)titleForMediaItemAtIndex:(NSUInteger)index;

/** Returns YES if the given media item occurs at least once in this collection
**/
- (BOOL)containsItem:(MPMediaItem *)compare;

/** Creates a new collection by appending otherCollection to the end of this collection
**/
- (MPMediaItemCollection *)collectionByAppendingCollection:(MPMediaItemCollection *)otherCollection;

/** Creates a new collection by appending an array of media items to the end of this collection
**/
- (MPMediaItemCollection *)collectionByAppendingMediaItems:(NSArray *)items;

/** Creates a new collection by appending a single media item to the end of this collection
**/
- (MPMediaItemCollection *)collectionByAppendingMediaItem:(MPMediaItem *)item;

/** Creates a new collection based on this collection, but excluding the specified items.
**/
- (MPMediaItemCollection *)collectionByDeletingMediaItems:(NSArray *)itemsToRemove;

/** Creates a new collection based on this collection, but which doesn't include the specified media item.
**/
- (MPMediaItemCollection *)collectionByDeletingMediaItem:(MPMediaItem *)itemToRemove;

/** Creates a new collection based on this collection, but excluding the media item at the specified index
**/
- (MPMediaItemCollection *)collectionByDeletingMediaItemAtIndex:(NSUInteger)index;

/** Creates a new collection, based on this collection, but excluding the media items starting with
(and including) the objects at index from and ending with (and including) to.
**/
- (MPMediaItemCollection *)collectionByDeletingMediaItemsFromIndex:(NSUInteger)from toIndex:(NSUInteger)to;
@end

MPMediaItemCollection-Utils.m

#import "Simple_PlayerViewController.h"
#import "MPMediaItemCollection-Utils.h"

@implementation Simple_PlayerViewController
@synthesize titleSearch;
@synthesize playPauseButton;
@synthesize tableView;
@synthesize player;
@synthesize collection;
@synthesize nowPlaying;

#pragma mark -
- (IBAction)doTitleSearch {
if ([titleSearch.text length] == 0)
return;
MPMediaPropertyPredicate *titlePredicate =
[MPMediaPropertyPredicate predicateWithValue: titleSearch.text
forProperty: MPMediaItemPropertyTitle
comparisonType:MPMediaPredicateComparisonContains];
MPMediaQuery *query = [[MPMediaQuery alloc] initWithFilterPredicates:[NSSet setWithObject:titlePredicate]];

if ([[query items] count] > 0) {
if (collection)
self.collection = [collection collectionByAppendingMediaItems:[query items]];
else
self.collection = [MPMediaItemCollection collectionWithItems:[query items]];

collectionModified = YES;
[self.tableView reloadData];
}
[query release];
titleSearch.text = @"";
[titleSearch resignFirstResponder];

}

- (IBAction)showMediaPicker {
MPMediaPickerController *picker = [[MPMediaPickerController alloc] initWithMediaTypes:MPMediaTypeMusic];
picker.delegate = self;
[picker setAllowsPickingMultipleItems:YES];
picker.prompt = NSLocalizedString(@"Select items to play", @"Select items to play");
[self presentModalViewController:picker animated:YES];
[picker release];
}

- (IBAction)backgroundClick {
[titleSearch resignFirstResponder];
}

- (IBAction)previousTrack {
[player skipToPreviousItem];
}

- (IBAction)nextTrack {
[player skipToNextItem];
}

- (IBAction)playOrPause {
if (player.playbackState == MPMusicPlaybackStatePlaying) {
[player pause];
[playPauseButton setBackgroundImage:[UIImage imageNamed:@"play.png"] forState:UIControlStateNormal];
}
else {
[player play];
[playPauseButton setBackgroundImage:[UIImage imageNamed:@"pause.png"] forState:UIControlStateNormal];
}
[self.tableView reloadData];
}

- (IBAction)removeTrack:(id)sender {
NSUInteger index = [sender tag];
MPMediaItem *itemToDelete = [collection mediaItemAtIndex:index];
if ([itemToDelete isEqual:nowPlaying])
[player skipToNextItem];
MPMediaItemCollection *newCollection = [collection collectionByDeletingMediaItemAtIndex:index];
self.collection = newCollection;
collectionModified = YES;

NSUInteger indices[] = {0, index};
NSIndexPath *deletePath = [NSIndexPath indexPathWithIndexes:indices length:2];
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:deletePath] withRowAnimation:UITableViewRowAnimationFade];
}

#pragma mark -
- (void)viewDidLoad {
MPMusicPlayerController *thePlayer = [MPMusicPlayerController iPodMusicPlayer];
self.player = thePlayer;
[thePlayer release];

if (player.playbackState == MPMusicPlaybackStatePlaying) {
[playPauseButton setBackgroundImage:[UIImage imageNamed:@"pause.png"] forState:UIControlStateNormal];
MPMediaItemCollection *newCollection = [MPMediaItemCollection collectionWithItems:[NSArray arrayWithObject:[player nowPlayingItem]]];
self.collection = newCollection;
self.nowPlaying = [player nowPlayingItem];
}
else {
[playPauseButton setBackgroundImage:[UIImage imageNamed:@"play.png"] forState:UIControlStateNormal];
}




NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
[notificationCenter addObserver: self
selector: @selector (nowPlayingItemChanged:)
name: MPMusicPlayerControllerNowPlayingItemDidChangeNotification
object: player];

[player beginGeneratingPlaybackNotifications];
}

- (void)viewDidUnload {
self.titleSearch = nil;
self.playPauseButton = nil;
self.tableView = nil;
[super viewDidUnload];
}

- (void)dealloc {
[titleSearch release];
[playPauseButton release];
[tableView release];
[player release];
[collection release];
[super dealloc];
}

#pragma mark -
#pragma mark Media Picker Delegate Methods
- (void) mediaPicker: (MPMediaPickerController *) mediaPicker
didPickMediaItems: (MPMediaItemCollection *) theCollection {  
[self dismissModalViewControllerAnimated: YES];

if (collection == nil){
self.collection = theCollection;
[player setQueueWithItemCollection:collection];
[player setNowPlayingItem:[collection firstMediaItem]];
self.nowPlaying = [collection firstMediaItem];
[player play];
[playPauseButton setBackgroundImage:[UIImage imageNamed:@"pause.png"] forState:UIControlStateNormal];
}
else {
self.collection = [collection collectionByAppendingCollection:theCollection];
}

collectionModified = YES;
[self.tableView reloadData];
}

- (void) mediaPickerDidCancel: (MPMediaPickerController *) mediaPicker {
[self dismissModalViewControllerAnimated: YES];
}

#pragma mark -
#pragma mark Player Notification Methods
- (void)nowPlayingItemChanged:(NSNotification *)notification {
if (![collection containsItem:[player nowPlayingItem]]) {
if (collectionModified) {
[player play];
[player setQueueWithItemCollection:collection];
[player setNowPlayingItem:[collection mediaItemAfterItem:nowPlaying]];
[playPauseButton setBackgroundImage:[UIImage imageNamed:@"pause.png"] forState:UIControlStateNormal];
}
else if ([player nowPlayingItem] != nil) {
MPMediaItem *nowPlayingItem = [player nowPlayingItem];
self.collection = [collection collectionByAppendingMediaItem:nowPlayingItem];
}
}
self.nowPlaying = [player nowPlayingItem];

if (nowPlaying == nil)
[playPauseButton setBackgroundImage:[UIImage imageNamed:@"play.png"] forState:UIControlStateNormal];

collectionModified = NO;
[self.tableView reloadData];
}

#pragma mark -
#pragma mark Table View Methods
- (NSInteger)tableView:(UITableView *)theTableView numberOfRowsInSection:(NSInteger)section {
return [collection count];
}

- (UITableViewCell *)tableView:(UITableView *)theTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *identifier = @"Music Queue Cell";
UITableViewCell *cell = [theTableView dequeueReusableCellWithIdentifier:identifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier] autorelease];

UIButton *removeButton = [UIButton buttonWithType:UIButtonTypeCustom];
UIImage *removeImage = [UIImage imageNamed:@"remove.png"];
[removeButton setBackgroundImage:removeImage forState:UIControlStateNormal];
[removeButton setFrame:CGRectMake(0.0, 0.0, removeImage.size.width, removeImage.size.height)];
[removeButton addTarget:self action:@selector(removeTrack:) forControlEvents:UIControlEventTouchUpInside];
cell.accessoryView  = removeButton;
}
cell.textLabel.text = [collection titleForMediaItemAtIndex:[indexPath row]];
if ([nowPlaying isEqual:[collection mediaItemAtIndex:[indexPath row]]]) {
cell.textLabel.font = [UIFont boldSystemFontOfSize:21.0];
if (player.playbackState ==  MPMusicPlaybackStatePlaying)
cell.imageView.image = [UIImage imageNamed:@"play_small.png"];
else
cell.imageView.image = [UIImage imageNamed:@"pause_small.png"];

}
else {
cell.textLabel.font = [UIFont systemFontOfSize:21.0];
cell.imageView.image = [UIImage imageNamed:@"empty.png"];
}

cell.accessoryView.tag = [indexPath row];


return cell;
}

- (void)tableView:(UITableView *)theTableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
MPMediaItem *selected = [collection mediaItemAtIndex:[indexPath row]];

if (collectionModified) {
[player setQueueWithItemCollection:collection];
}

[player setNowPlayingItem:selected];
[player play];

[playPauseButton setBackgroundImage:[UIImage imageNamed:@"pause.png"] forState:UIControlStateNormal];
[self.tableView reloadData];
}

- (CGFloat)tableView:(UITableView *)theTableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 34;
}

@end