iOS中的基本拖放功能 [英] Basic Drag and Drop in iOS

问题描述

我想要看到有车辆开车，用户也可以拖放。你认为最好的大规模战略是什么？从代表车辆的观点或从较大的角度来看触摸事件是否最好？你有一个简单的范例，你用来拖放你满意吗？不同策略的缺点是什么？

I want to have a view in which there are vehicles driving around that the user can also drag and drop. What do you think is the best large-scale strategy for doing this? Is it best to get touch events from the views representing the vehicles, or from the larger view? Is there a simple paradigm you've used for drag and drop that you're satisfied with? What are the drawbacks of different strategies?

推荐答案

假设你有一个 UIView 场景与背景图像和许多车辆，您可以将每个新车辆定义为 UIButton （UIImageView可能会工作也是）：

Assume you have a UIView scene with a background image and many vehicles, you may define each new vehicle as a UIButton (UIImageView will probably work too):

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button addTarget:self action:@selector(imageTouch:withEvent:) forControlEvents:UIControlEventTouchDown];
[button addTarget:self action:@selector(imageMoved:withEvent:) forControlEvents:UIControlEventTouchDragInside];
[button setImage:[UIImage imageNamed:@"vehicle.png"] forState:UIControlStateNormal];
[self.view addSubview:button];

然后，您可以通过回应 UIControlEventTouchDragInside 事件，例如：

Then you may move the vehicle wherever you want, by responding to the UIControlEventTouchDragInside event, e.g.:

- (IBAction) imageMoved:(id) sender withEvent:(UIEvent *) event
{
    CGPoint point = [[[event allTouches] anyObject] locationInView:self.view];
    UIControl *control = sender;
    control.center = point;
}

个人车辆处理自己的拖动更容易，与管理相比整个场景。

It's a lot easier for individual vehicle to handle its own drags, comparing to manage the scene as a whole.

这篇关于iOS中的基本拖放功能的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！