Question

我正在尝试在UITextView上实现水平滚动。我发现这解释了here.

但是，我不明白我如何'继承'UITextView。给出的代码和我试图实现的代码如下：

@interface SwipeableTextView : UITextView {
}

@end

@implementation SwipeableTextView

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    [self.superview touchesBegan:touches withEvent:event];

}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];

    [self.superview touchesMoved:touches withEvent:event];
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];

    [self.superview touchesEnded:touches withEvent:event];
} 

@end

显然，这应该覆盖正常UITextView，然后我可以通过引用SwipeableTextView（例如SwipeableTextView.text = @"Some Text";）来调用它。我的问题是，我在哪里放这段代码？在我的.m或.h文件中？我试图将它放在我的m文件的实现部分下面，但这不起作用，因为我已经有@interface和@implementation部分。非常感谢任何帮助。

编辑：现在有效：

//
//  SwipeTextView.h
//  Swipes
//

#import <Foundation/Foundation.h>

@interface SwipeTextView : UITextView {
    CGPoint     gestureStartPoint;
}

@property CGPoint gestureStartPoint;


@end

M档

//
//  SwipeTextView.m
//  Swipes
//

#import "SwipeTextView.h"
#define kMinimumGestureLength    10
#define kMaximumVariance         5

@implementation SwipeTextView
@synthesize gestureStartPoint;

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    UITouch *touch =[touches anyObject];
    gestureStartPoint = [touch locationInView:self.superview];

    [self.superview touchesBegan:touches withEvent:event];

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

    [super touchesMoved:touches withEvent:event];
    [self.superview touchesMoved:touches withEvent:event];

    UITouch *touch = [touches anyObject];
    CGPoint currentPosition = [touch locationInView:self.superview];

    CGFloat deltaXX = (gestureStartPoint.x - currentPosition.x); // positive = left, negative = right
    //CGFloat deltaYY = (gestureStartPoint.y - currentPosition.y); // positive = up, negative = down

    CGFloat deltaX = fabsf(gestureStartPoint.x - currentPosition.x); // will always be positive
    CGFloat deltaY = fabsf(gestureStartPoint.y - currentPosition.y); // will always be positive

    if (deltaX >= kMinimumGestureLength && deltaY <= kMaximumVariance) {
        if (deltaXX > 0) {
            NSLog (@"Horizontal Left swipe detected");
        }
        else {
            NSLog(@"Horizontal Right swipe detected");
        }

    }

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];

    [self.superview touchesEnded:touches withEvent:event];
} 




@end

最后，这就是我在ViewController中创建这个自定义UITextView的子类的方法：

// UITextView
CGRect aFrame = CGRectMake(0, 100, 320, 200);
aSwipeTextView = [[SwipeTextView alloc] initWithFrame:aFrame];
aSwipeTextView.text = @"Some sample text. Some sample text. Some sample text.";
[self.view addSubview:aSwipeTextView];

Answer 1

好的，这就是你做的。

如果要为对象创建子类，则为其创建.h和.m文件。

创建一个名为SwipeableTextView.h的文件，并将此代码插入其中：

#import <Foundation/Foundation.h>

    @interface SwipeableTextView : UITextView {

    }

@end

然后创建一个文件SwipeableTextView.m并将其插入其中：

#import "SwipeableTextView.h"

@implementation SwipeableTextView

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    [self.superview touchesBegan:touches withEvent:event];

}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];

    [self.superview touchesMoved:touches withEvent:event];
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];

    [self.superview touchesEnded:touches withEvent:event];
} 

@end

要在项目中使用此新子类，请执行以下操作。

导入标题：

#import "SwipeableTextView.h"

然后改为创建UITextView，你可以像这样创建SwipeableTextView：

SwipeableTextView *sTextView = [[SwipeableTextView alloc] init];

就是这样。希望它有所帮助。

如何子类化UITextView：实现水平滑动

1 个答案: