UIButton performance in UITableViewCell vs UIView
- by marcel salathe
I'd like to add a UIButton to a custom UITableViewCell (programmatically). This is easy to do, but I'm finding that the "performance" of the button in the cell is slow - that is, when I touch the button, there is quite a bit of delay until the button visually goes into the highlighted state. The same type of button on a regular UIView is very responsive in comparison.
In order to isolate the problem, I've created two views - one is a simple UIView, the other is a UITableView with only one UITableViewCell. I've added buttons to both views (the UIView and the UITableViewCell), and the performance difference is quite striking.
I've searched the web and read the Apple docs but haven't really found the cause of the problem. My guess is that it somehow has to do with the responder chain, but I can't quite put my finger on it. I must be doing something wrong, and I'd appreciate any help. Thanks.
Demo code:
ViewController.h
#import <UIKit/UIKit.h>
@interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
@property UITableView* myTableView;
@property UIView* myView;
ViewController.m
#import "ViewController.h"
#import "CustomCell.h"
@implementation ViewController
@synthesize myTableView, myView;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
[self initMyView];
[self initMyTableView];
}
return self;
}
- (void) initMyView {
UIView* newView = [[UIView alloc] initWithFrame:CGRectMake(0,0,[[UIScreen mainScreen] bounds].size.width,100)];
self.myView = newView;
// button on regularView
UIButton* myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[myButton addTarget:self action:@selector(pressedMyButton) forControlEvents:UIControlEventTouchUpInside];
[myButton setTitle:@"I'm fast" forState:UIControlStateNormal];
[myButton setFrame:CGRectMake(20.0, 10.0, 160.0, 30.0)];
[[self myView] addSubview:myButton];
}
- (void) initMyTableView {
UITableView *newTableView = [[UITableView alloc] initWithFrame:CGRectMake(0,100,[[UIScreen mainScreen] bounds].size.width,[[UIScreen mainScreen] bounds].size.height-100) style:UITableViewStyleGrouped];
self.myTableView = newTableView;
self.myTableView.delegate = self;
self.myTableView.dataSource = self;
}
-(void) pressedMyButton {
NSLog(@"pressedMyButton");
}
- (void)viewDidLoad {
[super viewDidLoad];
[[self view] addSubview:self.myView];
[[self view] addSubview:self.myTableView];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 1;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
CustomCell *customCell = [tableView dequeueReusableCellWithIdentifier:@"CustomCell"];
if (customCell == nil) {
customCell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"CustomCell"];
}
return customCell;
}
@end
CustomCell.h
#import <UIKit/UIKit.h>
@interface CustomCell : UITableViewCell
@property (retain, nonatomic) UIButton* cellButton;
@end
CustomCell.m
#import "CustomCell.h"
@implementation CustomCell
@synthesize cellButton;
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
// button within cell
cellButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[cellButton addTarget:self action:@selector(pressedCellButton) forControlEvents:UIControlEventTouchUpInside];
[cellButton setTitle:@"I'm sluggish" forState:UIControlStateNormal];
[cellButton setFrame:CGRectMake(20.0, 10.0, 160.0, 30.0)];
[self addSubview:cellButton];
}
return self;
}
- (void) pressedCellButton {
NSLog(@"pressedCellButton");
}
@end
