Mobile Application Development(Iphone): June 2014

Pull to Refresh in TableView

What I am going to do is.....

Step 1

create previous project

http://adrianmobileapplication.blogspot.com/2014/05/lazy-loading-step-1-first-create.html

Step 2

--------------------------do the changes to ViewController.h class......................

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UITableViewDataSource,UITableViewDelegate>

{

IBOutlet UITableView *profileTableView;

NSMutableArray *profileImageArray;

NSMutableArray *nameArray;

NSMutableArray *companyNameArray;

BOOL isDragging;

BOOL isLoading;

}

@property(strong,nonatomic) IBOutlet UITableView *profileTableView;

@property(strong,nonatomic) NSMutableArray *profileImageArray;

@property(strong,nonatomic) NSMutableArray *nameArray;

@property(strong,nonatomic) NSMutableArray *companyNameArray;

@property (nonatomic, retain) UIView *refreshHeaderView;

@property (nonatomic, retain) UILabel *refreshLabel;

@property (nonatomic, retain) UIImageView *refreshArrow;

@property (nonatomic, retain) UIActivityIndicatorView *refreshSpinner;

@property (nonatomic, copy) NSString *textPull;

@property (nonatomic, copy) NSString *textRelease;

@property (nonatomic, copy) NSString *textLoading;

- (void)setupStrings;

- (void)addPullToRefreshHeader;

- (void)startLoading;

- (void)stopLoading;

- (void)refresh;

@end

Step 3

---------------------------do the changes to ViewController.m class......................

#import "ViewController.h"

#import "CustomCell.h"

#define BUTTON_LEFT_MARGIN 10.0

#define BUTTON_SPACING 25.0

#define PUSH_STYLE_ANIMATION NO

#define REFRESH_HEADER_HEIGHT 52.0f

#define USE_GESTURE_RECOGNIZERS YES

// Bounce pixels define how many pixels the view is moved during the bounce animation

#define BOUNCE_PIXELS 5.0

@interface ViewController ()

@end

@implementation ViewController

@synthesize profileTableView,profileImageArray,companyNameArray,nameArray;

@synthesize textPull, textRelease, textLoading, refreshHeaderView, refreshLabel, refreshArrow, refreshSpinner;

#pragma mark - Life Cycle

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

if (self) {

// Custom initialization

}

return self;

}

- (void)viewDidLoad

{

[super viewDidLoad];

// Do any additional setup after loading the view from its nib.

[self setupStrings];

[self addPullToRefreshHeader];

profileImageArray =[[NSMutableArray alloc]initWithObjects:

@"http://upload.wikimedia.org/wikipedia/commons/e/eb/SLIIT_MLB_1.jpg",

@"https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGRrSBTxhJEVFgjD-bFIW8Qpqj4XFg4lk7B9J-KiPwdPTJTtHvBnZVKGUECOZc3ojXSj0ksd_jgkL5_fPd0MEYYVlNrQEccBtnvb8yRKQLsiYYXyh_qADCZjO9XJXMxv4_QVPNaMOYnEOp/s220/nwmpic.jpg",

@"http://www.userlogos.org/files/logos/robinhood/sliit400.png",

@"https://lh5.googleusercontent.com/-c6f2H9sAeDM/AAAAAAAAAAI/AAAAAAAAATM/9hzjaMbm4dM/photo.jpg",

@"https://lh4.googleusercontent.com/-qGRFN6zAkwA/AAAAAAAAAAI/AAAAAAAAAAA/2vec90BT9UQ/photo.jpg",

@"http://www.imagesbuddy.com/images/132/2014/01/purple-teddy-bear-happy-teddy-bear-day-2014.jpg",

@"https://lh3.googleusercontent.com/-8MeJ9g6xRso/AAAAAAAAAAI/AAAAAAAAAAA/1A6e1NaLimU/photo.jpg",

@"https://lh4.googleusercontent.com/-yaYTiufsV6I/AAAAAAAAAAI/AAAAAAAAAAA/TLDDaIWQ-Sk/photo.jpg",

@"http://www.interviewmagazine.com/files/2011/06/29/img-simon-van-booy_151144210967.png",

@"http://m.c.lnkd.licdn.com/mpr/pub/image-Dnol_IS4AkICXerqwCXULDwKFbuqEAnT7r_bL7l_Ftusk7LmDnobMsk4F33qksdVEyhq/ishara-sunjeewa.jpg",

nil];

nameArray =[[NSMutableArray alloc]initWithObjects:

@"Dhanushka Adrian",@"Dinithe",@"Nilakshan",@"Niron",@"Jude",

@"Malsha",@"Kasun",@"Thisra",@"Suranga",@"Ishara",

nil];

companyNameArray =[[NSMutableArray alloc]initWithObjects:

@"Vburst Software",@"Vburst Software",@"Vburst Software",@"EZCrM",

@"Chello Dairy Products(Pvt)Ltd",@"Vburst Software",@"Vburst Software",

@"Vburst Software",@"Vburst Software",@"Vburst Software",

nil];

}

- (void)didReceiveMemoryWarning

{

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

#pragma mark - Table Methods

- (NSInteger)tableView:(UITableView *)tableView

numberOfRowsInSection:(NSInteger)section

{

int nodeCount = [nameArray count];

if (nodeCount == 0){

return 1;

}

else{

NSLog(@"%d",nodeCount);

return nodeCount;

}

return 1;

}

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

{

NSLog(@"cellForRowAtIndexPath");

NSString *uniqueIdentifier = @"CustomCell";

CustomCell *cell = nil;

cell = (CustomCell *) [profileTableView dequeueReusableCellWithIdentifier:uniqueIdentifier];

if(!cell)

{

NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"CustomCell" owner:nil options:nil];

for(id currentObject in topLevelObjects)

{

if([currentObject isKindOfClass:[CustomCell class]])

{

cell = (CustomCell *)currentObject;

break;

}

cell.nameLabel.text = [nameArray objectAtIndex:indexPath.row];

cell.companyLabel.text = [companyNameArray objectAtIndex:indexPath.row];

NSString *AllPicUrl=[profileImageArray objectAtIndex:indexPath.row];

//image place holder---------------

[cell.profileImageView setImage:[UIImage imageNamed:@"defaultImgae.jpeg"]];

//Lazy Loading------------------------------------------

dispatch_queue_t imageQueue = dispatch_queue_create("imageDownloder", nil);

dispatch_async(imageQueue, ^{

//This is what you will load lazily

NSURL *imageUrl=[NSURL URLWithString:AllPicUrl];

NSData *imageData = [NSData dataWithContentsOfURL:imageUrl];

dispatch_sync(dispatch_get_main_queue(), ^{

cell.profileImageView.image = [UIImage imageWithData:imageData];;

[cell setNeedsLayout];

});

//--------------------------------------------------------

return cell;

}

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{

return 90.0f;

}

- (void)reloadTheTableView{

[self.profileTableView reloadData];

}

#pragma mark - Pull To Reload Method

- (void)refresh {

[self performSelector:@selector(addItem) withObject:nil afterDelay:2.0];

}

- (void)addItem {

// in here we can call webservice...

[self reloadTheTableView]; //for this i call the reload table view method

[self stopLoading];

}

- (void)setupStrings{

textPull = @"Pull down to refresh...";

textRelease = @"Release to refresh...";

textLoading = @"Loading...";

}

- (void)addPullToRefreshHeader {

refreshHeaderView = [[UIView alloc] initWithFrame:CGRectMake(0, 0 - REFRESH_HEADER_HEIGHT, 320, REFRESH_HEADER_HEIGHT)];

refreshHeaderView.backgroundColor = [UIColor clearColor];

refreshLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 320, REFRESH_HEADER_HEIGHT)];

refreshLabel.backgroundColor = [UIColor clearColor];

refreshLabel.font = [UIFont boldSystemFontOfSize:12.0];

refreshLabel.textAlignment = NSTextAlignmentCenter;

[refreshLabel setTextColor:[UIColor blackColor]];

refreshArrow = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"arrow.png"]];

refreshArrow.frame = CGRectMake(floorf((REFRESH_HEADER_HEIGHT - 27) / 2),

(floorf(REFRESH_HEADER_HEIGHT - 44) / 2),

27, 44);

refreshSpinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

refreshSpinner.frame = CGRectMake(floorf(floorf(REFRESH_HEADER_HEIGHT - 20) / 2), floorf((REFRESH_HEADER_HEIGHT - 20) / 2), 20, 20);

refreshSpinner.hidesWhenStopped = YES;

[refreshHeaderView addSubview:refreshLabel];

[refreshHeaderView addSubview:refreshArrow];

[refreshHeaderView addSubview:refreshSpinner];

[self.profileTableView addSubview:refreshHeaderView];

}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {

if (isLoading) {

if (scrollView.contentOffset.y > 0)

self.profileTableView.contentInset = UIEdgeInsetsZero;

else if (scrollView.contentOffset.y >= -REFRESH_HEADER_HEIGHT)

self.profileTableView.contentInset = UIEdgeInsetsMake(-scrollView.contentOffset.y, 0, 0, 0);

} else if (isDragging && scrollView.contentOffset.y < 0) {

[UIView animateWithDuration:0.25 animations:^{

if (scrollView.contentOffset.y < -REFRESH_HEADER_HEIGHT) {

refreshLabel.text = self.textRelease;

[refreshArrow layer].transform = CATransform3DMakeRotation(M_PI, 0, 0, 1);

} else {

refreshLabel.text = self.textPull;

[refreshArrow layer].transform = CATransform3DMakeRotation(M_PI * 2, 0, 0, 1);

}

}];

}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {

if (isLoading) return;

isDragging = NO;

if (scrollView.contentOffset.y <= -REFRESH_HEADER_HEIGHT) {

[self startLoading];

}

- (void)startLoading {

isLoading = YES;

[UIView animateWithDuration:0.3 animations:^{

self.profileTableView.contentInset = UIEdgeInsetsMake(REFRESH_HEADER_HEIGHT, 0, 0, 0);

refreshLabel.text = self.textLoading;

refreshArrow.hidden = YES;

[refreshSpinner startAnimating];

}];

[self refresh];

}

- (void)stopLoading {

isLoading = NO;

[UIView animateWithDuration:0.3 animations:^{

self.profileTableView.contentInset = UIEdgeInsetsZero;

[refreshArrow layer].transform = CATransform3DMakeRotation(M_PI * 2, 0, 0, 1);

}

completion:^(BOOL finished) {

[self performSelector:@selector(stopLoadingComplete)];

}];

}

- (void)stopLoadingComplete {

refreshLabel.text = self.textPull;

refreshArrow.hidden = NO;

[refreshSpinner stopAnimating];

}

@end

Step 4

Run the Project

Monday, June 2, 2014

Pull to Refresh in TableView