单指移动光标手势，双指修改文本选区手势

` UIView ` 通过实现 ` UITextInput ` 协议，实现单指移动光标手势，双指修改文本选区手势。
分别使用了 ` UIPanGestureRecognizer ` 和 ` UIPinchGestureRecognizer ` 手势。

#import "ViewController.h"
#import "JSWebView.h"
#import "UIView+Constriant.h" <!--more-->    #import "JSInputView.h"
#import "UIResponder+FirstResponder.h"
#import "NSObject+SetFrame.h"

#import "WebViewJavascriptBridge.h"

@interface ViewController () <UIWebViewDelegate>

@property (nonatomic, strong) JSWebView *webView;
@property (nonatomic, strong) NSLayoutConstraint *bottomConstraint;
//@property WebViewJavascriptBridge* bridge;
@property (nonatomic, assign) CGPoint lastPoint;
@property (nonatomic, assign) CGPoint startPoint0;
@property (nonatomic, assign) CGPoint startPoint1;
@property (nonatomic, assign) CGRect lastRect0;
@property (nonatomic, assign) CGRect lastRect1;
@property (nonatomic, assign) CGRect startRect0;
@property (nonatomic, assign) CGRect startRect1;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    /*……*/
    //单指移动光标手势    
    UIPanGestureRecognizer *singleFingerPanRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(singleFingerMoveCursor:)];
    singleFingerPanRecognizer.maximumNumberOfTouches = 1;
    [self.webView.keyboard addGestureRecognizer:singleFingerPanRecognizer];
    //双指选择选区手势
    UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchSelect:)];
    [self.webView.keyboard addGestureRecognizer:pinchGesture];

    self.lastRect0 = CGRectMake(0, 0, 1, 19);
    self.lastRect1 = CGRectMake(0, 0, 1, 19);
    self.startPoint0 = CGPointMake(0, 0);
    self.startPoint1 = CGPointMake(0, 0);
    self.lastPoint = CGPointMake(0, 0);

    [self loadWeb];
}

#pragma mark - keyboard gesture
//单个手指移动光标
- (void)singleFingerMoveCursor: (UIPanGestureRecognizer *)sender {
    UIResponder <UITextInput>*textInput = [UIResponder currentFirstResponder];
    if (sender.state == UIGestureRecognizerStateBegan) {
        self.lastPoint = CGPointMake(0, 0);
        CGPoint cursorPoint = [textInput caretRectForPosition:textInput.selectedTextRange.start].origin;
        self.lastRect0 = CGRectMake(cursorPoint.x, cursorPoint.y, 20, 20);
    } else if (sender.state == UIGestureRecognizerStateChanged) {
//        NSString *webString = [self.webView stringByEvaluatingJavaScriptFromString:@"document.body.innerText"];

        CGRect newFrame = CGRectMake(self.lastRect0.origin.x + [sender translationInView:self.webView.keyboard].x - self.lastPoint.x, self.lastRect0.origin.y + [sender translationInView:self.webView.keyboard].y - self.lastPoint.y, self.lastRect0.size.width, self.lastRect0.size.height);
        CGPoint cursorPoint;
        if ([sender translationInView:self.webView.keyboard].y > 0) {
            cursorPoint = CGPointMake(newFrame.origin.x, newFrame.origin.y);
        } else if ([sender translationInView:self.webView.keyboard].y < 0) {
            cursorPoint = CGPointMake(newFrame.origin.x, newFrame.origin.y + newFrame.size.height);
        } else {
            cursorPoint = CGPointMake(newFrame.origin.x, newFrame.origin.y + newFrame.size.height / 2);
        }

        UITextPosition *pos = [textInput closestPositionToPoint:cursorPoint];
        UITextRange *textRange = [textInput textRangeFromPosition:pos toPosition:pos];
        textInput.selectedTextRange = textRange;

        self.lastRect0 = newFrame;

        self.lastPoint = CGPointMake([sender translationInView:self.webView.keyboard].x, [sender translationInView:self.webView.keyboard].y);
    }
}
static bool isReverse; //左右手指是否和locationOfTouch:检测结果相反
//双指移动选择文字手势
- (void)pinchSelect:(UIPinchGestureRecognizer *)sender {
    UIResponder <UITextInput>*textInput = [UIResponder currentFirstResponder];
    if (sender.state == UIGestureRecognizerStateBegan) {
        self.startPoint0 = [sender locationOfTouch:0 inView:self.webView.keyboard];
        self.startPoint1 = [sender locationOfTouch:1 inView:self.webView.keyboard];
        isReverse = false;
        if (self.startPoint0.x > self.startPoint1.x) {  //左右手指相反
            CGPoint temp;
            temp = self.startPoint0;
            self.startPoint0 = self.startPoint1;
            self.startPoint1 = temp;
            isReverse = true;
        }
        if (textInput.selectedTextRange.isEmpty){   //是否有选区
            self.startRect0 = [textInput caretRectForPosition:textInput.selectedTextRange.start];
            self.startRect1 = [textInput caretRectForPosition:textInput.selectedTextRange.start];
        } else {
            self.startRect0 = [textInput caretRectForPosition:textInput.selectedTextRange.start];
            self.startRect1 = [textInput caretRectForPosition:textInput.selectedTextRange.end];
        }
        self.lastRect0 = self.startRect0;
        self.lastRect1 = self.startRect1;
    } else if (sender.state == UIGestureRecognizerStateChanged) {
        if ([sender numberOfTouches] == 2) {
            float deltaX;
            float deltaY;
            //左边手指移动距离
            if (isReverse) {
                deltaX = [sender locationOfTouch:1 inView:self.webView.keyboard].x - self.startPoint0.x;
                deltaY = [sender locationOfTouch:1 inView:self.webView.keyboard].y - self.startPoint0.y;
            } else {
                deltaX = [sender locationOfTouch:0 inView:self.webView.keyboard].x - self.startPoint0.x;
                deltaY = [sender locationOfTouch:0 inView:self.webView.keyboard].y - self.startPoint0.y;
            }
            self.lastRect0 = CGRectMake(self.startRect0.origin.x, self.startRect0.origin.y, self.startRect0.size.width, self.startRect0.size.height);
            if (deltaY > 0) {
                self.lastRect0 = [self frame:_lastRect0 withPoint:CGPointMake(self.lastRect0.origin.x + deltaX, self.lastRect0.origin.y + deltaY)];//CGRectMake(self.lastRect0.origin.x + deltaX, self.lastRect0.origin.y + deltaY, 20, 20);
            } else if (deltaY < 0) {
                self.lastRect0 = [self frame:_lastRect0 withPoint:CGPointMake(self.lastRect0.origin.x + deltaX, self.lastRect0.origin.y + deltaY + self.lastRect0.size.height * 0.9)];
            } else {
                self.lastRect0 = [self frame:_lastRect0 withPoint:CGPointMake(self.lastRect0.origin.x + deltaX, self.lastRect0.origin.y + deltaY + self.lastRect0.size.height * 0.5)];
            }

            //右边手指移动
            if (isReverse) {
                deltaX = [sender locationOfTouch:0 inView:self.webView.keyboard].x - self.startPoint1.x;
                deltaY = [sender locationOfTouch:0 inView:self.webView.keyboard].y - self.startPoint1.y;
            } else {
                deltaX = [sender locationOfTouch:1 inView:self.webView.keyboard].x - self.startPoint1.x;
                deltaY = [sender locationOfTouch:1 inView:self.webView.keyboard].y - self.startPoint1.y;
            }
            self.lastRect1 = [self frame:_lastRect1 withPoint:CGPointMake(self.startRect1.origin.x, self.startRect1.origin.y)];
            if (deltaY > 0) {
                self.lastRect1 = [self frame:_lastRect1 withPoint:CGPointMake(self.lastRect1.origin.x + deltaX, self.lastRect1.origin.y + deltaY)];;
            } else if (deltaY < 0) {
                self.lastRect1 = [self frame:_lastRect1 withPoint:CGPointMake(self.lastRect1.origin.x + deltaX, self.lastRect1.origin.y + deltaY + self.lastRect1.size.height * 0.9)];;
            } else {
                self.lastRect1 = [self frame:_lastRect1 withPoint:CGPointMake(self.lastRect1.origin.x + deltaX, self.lastRect1.origin.y + deltaY + self.lastRect1.size.height * 0.5)];;
            }

            UITextPosition *textPoint0 = [textInput closestPositionToPoint:self.lastRect0.origin];
            UITextPosition *textPoint1 = [textInput closestPositionToPoint:self.lastRect1.origin];
            textInput.selectedTextRange = [textInput textRangeFromPosition:textPoint0 toPosition:textPoint1];
        }
    }
}