objective-c - 从固定的 UIImageView 或按钮中拖出新的 UIImageView 对象
<p><p>我是 iOS 开发的初学者，我正在为我的学校做一个业余项目。我想做的是有一个小图像，用户可以从中拖出更多图像。本质上，我有一个应用程序，我正在生成方 block ，我需要有一个固定方 block ，用户可以在其中触摸方 block 并将新方 block 拖到板上。我已经实现了这一点，但这还不是理想的行为。目前，用户必须先触摸按钮然后松开，然后才能与新方 block 进行交互以将其拖离按钮。我想要的是让触摸事件以某种方式传递给创建的新 UIImageView 对象，这样它就可以无缝地拖出一个新的正方形。以下是我当前的代码。</p>
<pre><code>//UIViewController
#import <UIKit/UIKit.h>
#import "Tile.h"
@interface MenuViewController : UIViewController
{
Tile *tileObject;
}
@end
#import "MenuViewController.h"
@implementation MenuViewController
- (IBAction)createTile:(UIButton *)sender {
CGFloat tileX = sender.center.x;
CGFloat tileY = sender.center.y;
tileObject = [initWithX:tileX andY:tileY];
;
}
- (void)didReceiveMemoryWarning
{
;
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
;
// Do any additional setup after loading the view, typically from a nib.
}
- (void)viewDidUnload
{
;
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return YES;
}
@end
//Custom Tile Class
#import <UIKit/UIKit.h>
@interface Tile : UIImageView
{
CGPoint startLocation;
}
- (id)init; //Default Initialization
- (id)initWithX:(CGFloat)x andY:(CGFloat)y; //Initialization with coordinate points from single screen tap
@end
#import "Tile.h"
@implementation Tile
//Default initialization
-(id) init
{
self = ;
return self;
}
//Initialization with coordinate points from single screen tap
- (id)initWithX:(CGFloat)centerX andY:(CGFloat)centerY
{
//Creates a UIImageView object from an image file
UIImage *image = ;
self = ;
//Used to center the image under the single screen tap
centerX -= (image.size.height/2);
centerY -= (image.size.height/2);
//Sets the position of the image
self.frame = CGRectMake(centerX, centerY, image.size.width, image.size.height);
self.userInteractionEnabled = YES; //required for interacting with UIImageViews
return self;
}
/* Methods from Stack Overflow
http://stackoverflow.com/questions/1991899/uiimage-detecting-touch-and-dragging
Referenced from http://www.iphoneexamples.com/
*/
- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
// Retrieve the touch point
CGPoint point = [ locationInView:self];
startLocation = point;
[ bringSubviewToFront:self];
}
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
// Move relative to the original touch point
CGPoint point = [ locationInView:self];
CGRect frame = ;
frame.origin.x += point.x - startLocation.x;
frame.origin.y += point.y - startLocation.y;
;
}
/*
end of methods from Stack Overflow
*/
@end
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>如果初始触地点可以是一个 ImageView ，其中您要拖动的图像作为其图像，那么您可以这样做:</p>
<p>在您的 menuViewController 类中，将其放入 viewDidLoad(并删除按钮及其方法):</p>
<pre><code>- (void)viewDidLoad
{
;
tileObject = [initWithX:160 andY:200];
;
}
</code></pre>
<p>然后在你的 Tile 类中，在 touchesBegan:withEvent: 方法中创建一个新的 tile，并像以前一样执行拖动操作:</p>
<pre><code>- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
Tile *newTile = [initWithX:160 andY:200];
;
// Retrieve the touch point
CGPoint point = [ locationInView:self];
startLocation = point;
[ bringSubviewToFront:self];
}
</code></pre></p>
<p style="font-size: 20px;">关于objective-c - 从固定的 UIImageView 或按钮中拖出新的 UIImageView 对象，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/10740272/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/10740272/
</a>
</p>
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