UIButton在按下时保持突出显示

Question

This is quite frustrating and I searched a LOT to no avail.

I have one button. When it is pressed it calls a method that performs a network action (NSURLRequest).

The button should do the following:

• When pressed: Show the pressed state image, fire the request method
• After pressed: Show the disabled state of the button until method completes request

The problem is the button is STAYING in the highlighted/pressed state throughout the request. I have attached code I currently have below.

For the Button:

[myButton setBackgroundImage:[UIImage imageNamed:@"defaultbutton"] forState:UIControlStateNormal];
[myButton setBackgroundImage:[UIImage imageNamed:@"pressedbutton"] forState:UIControlStateHighlighted];
[myButton setBackgroundImage:[UIImage imageNamed:@"disabledbutton"] forState:(UIControlStateDisabled|UIControlStateSelected)];
[squishButton addTarget:self action:@selector(reqMethod) forControlEvents:UIControlEventTouchUpInside];

In the method at the start of the request:

-(void)reqMethod {
NSLog(@"Starting request..");
[myButton setHighlighted:NO];
[myButton setEnabled:NO];
[myButton setSelected:YES];

When the request completes it hides the normal button and shows a reset button which works fine.

Answer 1

You should have a view at multithreading documentation. http://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/Multithreading/Introduction/Introduction.html

If you want a piece of code I think that this could be useful

[myButton setBackgroundImage:[UIImage imageNamed:@"defaultbutton"] forState:UIControlStateNormal];
[myButton setBackgroundImage:[UIImage imageNamed:@"pressedbutton"] forState:UIControlStateHighlighted];
[myButton setBackgroundImage:[UIImage imageNamed:@"disabledbutton"] forState:(UIControlStateDisabled|UIControlStateSelected)];
[squishButton addTarget:self action:@selector(reqMethod) forControlEvents:UIControlEventTouchUpInside];

    dispatch_async(dispatch_get_global_queue(0, 0), 
                       ^{
                           //Your request
    dispatch_async(dispatch_get_main_queue(), 
                           ^{
                   NSLog(@"Starting request..");
                   [myButton setHighlighted:NO];
                   [myButton setEnabled:NO];
                   [myButton setSelected:YES];  
                     });
                });

Answer 2

Why dont you do network operation on background thread :

- (IBAction)buttonPressed:(UIButton *)button 
{

    [NSThread detachNewThreadSelector:@selector(doSomeNetworkStuff) toTarget:self    withObject:nil];
}

Answer 3

This will keep the button highlighted when you press it for the first time (you can alter it to work with images). If you press it again, it will become unhighlighted. (I know the syntax looks weird, just try it...it works)

@property (nonatomic) BOOL buttonHighlighted

// IBAction called when button pressed the first time
- (IBAction)buttonPressed:(UIButton *)button 
{
    [[NSOperationQueue mainQueue] addOperationWithBlock:^{
        if(self.buttonHighlighted)
        {
            button.highlighted = NO;
            self.buttonHighlighted = NO;
        }
        else
        {
            button.highlighted = YES;
            self.buttonHighlighted = YES;
            //Fire request method
        }
    }];
}

Now, just call this method again when your request is finished.