我如何从viewdidload调用按钮的方法

Question

I have 10 UIButton objects. I define a single action for all of them. I want to animate the UIScrollView to a desired image location when I on the related button. I have implemented this project using storyboards and I have one method for all 10 buttons. I gave a tag to each button in viewDidLoad in viewcontroller.m file like this

button1.tag = 10;
button1.tag = 11;
button1.tag = 12;
button1.tag = 13;
button1.tag = 14;
button1.tag = 15;
button1.tag = 16;
button1.tag = 17;
button1.tag = 18;
button1.tag = 19;

// viewcontroller.m file

-(IBAction) Button1:(id) sender
{

 [self performSegueWithIdentifier:@"nextView" sender:sender];
}

This button method will take me to nextviewcontroller and its working fine, but in nextviewctontroller.m file i want to animate my UIScrollView to desired location. I am doing it like this in nextviewcontroller.m file, but its not working.

viewDidload
{
if ([sender tag] == 10)
{
[yourScrollView scrollRectToVisible:CGRectMake(0,0,100,100) animated:YES];
}
else if ([sender tag] == 11)
{
[yourScrollView scrollRectToVisible:CGRectMake(320,0,100,100) animated:YES];
}
/*
.
.
.
.
.
.
.
and its continue to the last tag 
*/

}

It does not animate the UIScrollView to the desired location and one thing remember here I have declared sender as type id in header file. Kindly tell me how I can animate UIScrollView to the desired location when I click on corresponding button. I also wanted to say I did not copy and paste this code from my xcode project. I wrote this code just give you idea what I want.

Answer 1

At this point, you are in your second viewController and no longer have access to the tags on your buttons. They are out of scope at that point unless you have a reference to the first view controller (which you shouldn't).

You should create a tag or offset property on your "nextViewController". Then, depending on how you get there from the first view controller, you need to have the first view controller set that property on the second. Then you can access it in your second. If you are using segue you should do this in the prepareForSegue method of the first view controller.

If you are pushing it on a navigation controller, you would set that property after allocating the second view controller and before pushing it onto the navigation stack.

Answer 2

In the header of the next view controller add this

@property (nonatomic, strong) UIButton *buttonBeingPassedIn;

In the first View controller you want to create a UIButton globally so you can access it in any method in that file, call it something like: buttonThatWasTapped. Then you can do something like this:

-(IBAction) Button1:(id) sender
{
    buttonBeingPassedIn = (UIButton *)sender;
    // Notice this has been changed to sender: self
    [self performSegueWithIdentifier:@"nextView" sender:self];
}

In the first view controller you need to add this method

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
      nextViewController *vc = (nextViewController *)segue.destinationViewController;
      vc.buttonBeingPassedIn = buttonThatWasTapped;
}

Then you will be able to do

viewDidload
{
    if (buttonBeingPassedIn == 10)
}

Answer 3

Try doing this in viewWillAppear instead of viewDidLoad. You shouldn't put geometry-related stuff in viewDidLoad as the view's geometry (frame etc) is not set at that point.