objective-c - 识别用户手势的路径
<p><p>我正在开发一个屏幕上有 9 个 View 的应用程序，我希望用户以他们想要的方式连接 View ，并将他们的序列记录为密码。
但我不知道我应该使用哪个手势识别器。</p>
<p>我应该使用 CMUnistrokeGestureRecognizer 还是几个滑动手势的组合或其他什么？
谢谢。</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>您可以使用 <a href="http://developer.apple.com/library/ios/#documentation/uikit/reference/UIPanGestureRecognizer_Class/Reference/Reference.html" rel="noreferrer noopener nofollow"><code>UIPanGestureRecognizer</code></a> ，类似:</p>
<pre><code>CGFloat const kMargin = 10;
- (void)viewDidLoad
{
;
// create a container view that all of our subviews for which we want to detect touches are:
CGFloat containerWidth = fmin(self.view.bounds.size.width, self.view.bounds.size.height) - kMargin * 2.0;
UIView *container = [ initWithFrame:CGRectMake(kMargin, kMargin, containerWidth, containerWidth)];
container.backgroundColor = ;
;
// now create all of the subviews, specifying a tag for each; and
CGFloat cellWidth = (containerWidth - (4.0 * kMargin)) / 3.0;
for (NSInteger column = 0; column < 3; column++)
{
for (NSInteger row = 0; row < 3; row++)
{
UIView *cell = [ initWithFrame:CGRectMake(kMargin + column * (cellWidth + kMargin),
kMargin + row * (cellWidth + kMargin),
cellWidth, cellWidth)];
cell.tag = row * 3 + column;
cell.backgroundColor = ;
;
}
}
// finally, create the gesture recognizer
UIPanGestureRecognizer *pan = [ initWithTarget:self
action:@selector(handlePan:)];
;
}
- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static NSMutableArray *gesturedSubviews;
// if we're starting a gesture, initialize our list of subviews that we've gone over
if (gesture.state == UIGestureRecognizerStateBegan)
{
gesturedSubviews = ;
}
// now figure out whether:
// (a) are we over a subview; and
// (b) is this a different subview than we last were over
CGPoint location = ;
for (UIView *subview in gesture.view.subviews)
{
if (CGRectContainsPoint(subview.frame, location))
{
if (subview != )
{
;
// an example of the sort of graphical flourish to give the
// some visual cue that their going over the subview in question
// was recognized
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionAutoreverse
animations:^{
subview.alpha = 0.5;
}
completion:^(BOOL finished){
subview.alpha = 1.0;
}];
}
}
}
// finally, when done, let's just log the subviews
// you would do whatever you would want here
if (gesture.state == UIGestureRecognizerStateEnded)
{
NSLog(@"We went over:");
for (UIView *subview in gesturedSubviews)
{
NSLog(@"%d", subview.tag);
}
// you might as well clean up your static variable when you're done
gesturedSubviews = nil;
}
}
</code></pre>
<p>显然，您可以按自己的方式创建 subview ，并以任何方式跟踪它们，但我们的想法是让 subview 具有唯一的 <code>tag</code> 编号，而手势识别器只需查看您以一个手势遍历它们的顺序。 </p>
<p>即使我没有准确捕捉到您想要的内容，它至少向您展示了如何使用平移手势识别器来跟踪手指从一个 subview 到另一个 subview 的移动。</p>
<hr/>
<p><strong>更新:</strong></p>
<p>如果您想在用户登录时在屏幕上绘制路径，您可以使用 <code>UIBezierPath</code> 创建一个 <code>CAShapeLayer</code>。我将在下面演示，但作为警告，我不得不指出这可能不是一个很好的安全功能:通常输入密码时，你会向用户展示足够多的内容，以便他们确认他们正在做他们想要什么，但还不够，以至于有人可以回头看看整个密码是什么。输入文本密码时，通常 iOS 会暂时显示您按下的最后一个键，但很快会将其转换为星号，这样您就无法看到整个密码。这就是我最初的建议。</p>
<p>但是，如果您真的一心想在用户绘制路径时向他们展示路径，您可以使用类似以下的内容。首先，这需要<a href="https://developer.apple.com/library/ios/#documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/Introduction/Introduction.html" rel="noreferrer noopener nofollow">Quartz 2D</a> .因此将 <code>QuartzCore.framework</code> 添加到您的项目中(参见 <a href="http://developer.apple.com/library/ios/#recipes/xcode_help-project_editor/Articles/AddingaLibrarytoaTarget.html" rel="noreferrer noopener nofollow">Linking to a Library or Framework</a> )。二、导入QuartCore头文件:</p>
<pre><code>#import <QuartzCore/QuartzCore.h>
</code></pre>
<p>第三，将 pan 处理程序替换为:</p>
<pre><code>- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static NSMutableArray *gesturedSubviews;
static UIBezierPath *path = nil;
static CAShapeLayer *shapeLayer = nil;
// if we're starting a gesture, initialize our list of subviews that we've gone over
if (gesture.state == UIGestureRecognizerStateBegan)
{
gesturedSubviews = ;
}
// now figure out whether:
// (a) are we over a subview; and
// (b) is this a different subview than we last were over
CGPoint location = ;
for (UIView *subview in gesture.view.subviews)
{
if (!path)
{
// if the path hasn't be started, initialize it and the shape layer
path = ;
;
shapeLayer = [ init];
shapeLayer.strokeColor = .CGColor;
shapeLayer.fillColor = .CGColor;
shapeLayer.lineWidth = 2.0;
;
}
else
{
// otherwise add this point to the layer's path
;
shapeLayer.path = path.CGPath;
}
if (CGRectContainsPoint(subview.frame, location))
{
if (subview != )
{
;
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionAutoreverse
animations:^{
subview.alpha = 0.5;
}
completion:^(BOOL finished){
subview.alpha = 1.0;
}];
}
}
}
// finally, when done, let's just log the subviews
// you would do whatever you would want here
if (gesture.state == UIGestureRecognizerStateEnded)
{
// assuming the tags are numbers between 0 and 9 (inclusive), we can build the password here
NSMutableString *password = ;
for (UIView *subview in gesturedSubviews)
;
NSLog(@"Password = %@", password);
// clean up our array of gesturedSubviews
gesturedSubviews = nil;
// clean up the drawing of the path on the screen the user drew
;
shapeLayer = nil;
path = nil;
}
}
</code></pre>
<p>这会产生用户在手势进行时绘制的路径:</p>
<p> <img src="/image/Be1IO.png" alt="path of user's finger"/> </p>
<p>与其显示用户每次手指移动所绘制的路径，不如在 subview 的中心之间画线，例如:</p>
<pre><code>- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static NSMutableArray *gesturedSubviews;
static UIBezierPath *path = nil;
static CAShapeLayer *shapeLayer = nil;
// if we're starting a gesture, initialize our list of subviews that we've gone over
if (gesture.state == UIGestureRecognizerStateBegan)
{
gesturedSubviews = ;
}
// now figure out whether:
// (a) are we over a subview; and
// (b) is this a different subview than we last were over
CGPoint location = ;
for (UIView *subview in gesture.view.subviews)
{
if (CGRectContainsPoint(subview.frame, location))
{
if (subview != )
{
;
if (!path)
{
// if the path hasn't be started, initialize it and the shape layer
path = ;
;
shapeLayer = [ init];
shapeLayer.strokeColor = .CGColor;
shapeLayer.fillColor = .CGColor;
shapeLayer.lineWidth = 2.0;
;
}
else
{
// otherwise add this point to the layer's path
;
shapeLayer.path = path.CGPath;
}
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionAutoreverse
animations:^{
subview.alpha = 0.5;
}
completion:^(BOOL finished){
subview.alpha = 1.0;
}];
}
}
}
// finally, when done, let's just log the subviews
// you would do whatever you would want here
if (gesture.state == UIGestureRecognizerStateEnded)
{
// assuming the tags are numbers between 0 and 9 (inclusive), we can build the password here
NSMutableString *password = ;
for (UIView *subview in gesturedSubviews)
;
NSLog(@"Password = %@", password);
// clean up our array of gesturedSubviews
gesturedSubviews = nil;
// clean up the drawing of the path on the screen the user drew
;
shapeLayer = nil;
path = nil;
}
}
</code></pre>
<p>这会产生如下内容:</p>
<p> <img src="/image/2ZMp6.png" alt="user path with lines"/> </p>
<p>您有各种各样的选择，但希望您现在拥有构建模块，以便您可以设计自己的解决方案。</p></p>
<p style="font-size: 20px;">关于objective-c - 识别用户手势的路径，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/14161405/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/14161405/
</a>
</p>
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