此平移手勢識別器操作有什麼問題？

我不確定當我移動視圖時爲什麼不能平移？此平移手勢識別器操作有什麼問題？

CGPoint translation = [recognizer translationInView:self.view]; 


    if ((recognizer.view.frameY + translation.y >= self.view.frameHeight - recognizer.view.frameHeight)) { 
     CGPoint newOrigin = CGPointMake(self.view.bounds.size.width, roundf(recognizer.view.frameY + translation.y)); 
     recognizer.view.frameOrigin = newOrigin; 
     NSLog(@"FRAME ORIGIN %@", NSStringFromCGPoint(recognizer.view.frameOrigin)); 
    }

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2012-12-20 adit

我不承認'frameY'，'frameHeight'，'frameOrigin'等。這只是對實際代碼的簡寫（如：'frame.origin.y'，'frame.size.height' ，「frame.origin」等）。但我同意列維的直覺，認爲這種不平等看起來很落後。我也發現''translation.y'重複添加到'frame.origin.y'令人擔憂。我會使用視圖的原始「原點」（除非您每次都重置翻譯，這是我不會瘋狂的做法）。最後，你將'frame.origin.x'設置爲'self.view.bounds.size.width'的_x_ ......這將它放在屏幕上，不是？你看到任何NSLog？ – Rob

我不清楚一些自定義變量之類的東西，所以而非調試代碼，我想我會告訴你我會怎麼使用UIPanGestureRecognizer做一個視圖的拖動。

因此，假定（a）該手勢已被添加到該視圖被拖動;及（b）該視圖包含要約束視圖的運動的上海華之內，代碼可能看起來像：

- (void)handlePan:(UIPanGestureRecognizer *)gesture 
{ 
    static CGRect originalFrame; 

    if (gesture.state == UIGestureRecognizerStateBegan) 
    { 
     originalFrame = gesture.view.frame; 
    } 
    else if (gesture.state == UIGestureRecognizerStateChanged) 
    { 
     CGPoint translate = [gesture translationInView:gesture.view.superview]; 
     CGRect newFrame = CGRectMake(originalFrame.origin.x + translate.x, 
            originalFrame.origin.y + translate.y, 
            originalFrame.size.width, 
            originalFrame.size.height); 

     if (CGRectContainsRect(gesture.view.superview.bounds, newFrame)) 
      gesture.view.frame = newFrame; 
    } 
}

雖然上述中享有一定的簡單性，我認爲我們可以在對提高用戶體驗。值得注意的是，如果用戶將視圖拖到超級視圖之外（例如，拖過左邊框並在那裏凍結，即使您上下移動手指;不是很優雅），上面的代碼也不會執行任何操作。我認爲以下是一個更加優雅的用戶界面（但是閱讀代碼稍微複雜一點），當用戶拖動他們的手指時，我們將拖動對象到超級視圖中最接近的點，用戶的手指是。

- (void)handlePan:(UIPanGestureRecognizer *)gesture 
{ 
    static CGRect originalFrame; 

    if (gesture.state == UIGestureRecognizerStateBegan) 
    { 
     originalFrame = gesture.view.frame; 
    } 
    else if (gesture.state == UIGestureRecognizerStateChanged) 
    { 
     CGPoint translate = [gesture translationInView:gesture.view.superview]; 
     CGRect newFrame = CGRectMake(fmin(gesture.view.superview.frame.size.width - originalFrame.size.width, fmax(originalFrame.origin.x + translate.x, 0.0)), 
            fmin(gesture.view.superview.frame.size.height - originalFrame.size.height, fmax(originalFrame.origin.y + translate.y, 0.0)), 
            originalFrame.size.width, 
            originalFrame.size.height); 

     gesture.view.frame = newFrame; 
    } 
}

來源

2012-12-23 18:36:36 Rob

這個很好用，謝謝！ – zic10

在if你應該寫<=代替>=，因爲原產地是在左上角

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2012-12-20 21:32:54 Levi

難道叫平移手勢的方法？如果未設置用戶交互啓用。你可以使用下面的代碼。

- (void)handlePan:(UIPanGestureRecognizer *)recognizer { 


CGPoint translation = [recognizer translationInView:recognizer.view.superview]; 

recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, 
            recognizer.view.center.y + translation.y); 
[recognizer setTranslation:CGPointMake(0, 0) inView:recognizer.view.superview]; 

if (recognizer.state == UIGestureRecognizerStateEnded) { 

    CGPoint velocity = [recognizer velocityInView:recognizer.view.superview]; 
    CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y)); 
    CGFloat slideMult = magnitude/200; 
    NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult); 

    float slideFactor = 0.1 * slideMult; // Increase for more of a slide 
    CGPoint finalPoint = CGPointMake(recognizer.view.center.x + (velocity.x * slideFactor), 
            recognizer.view.center.y + (velocity.y * slideFactor)); 
    finalPoint.x = MIN(MAX(finalPoint.x, 0), recognizer.view.superview.bounds.size.width); 
    finalPoint.y = MIN(MAX(finalPoint.y, 0), recognizer.view.superview.bounds.size.height); 

    [UIView animateWithDuration:slideFactor*2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{ 
     recognizer.view.center = finalPoint; 
    } completion:nil]; 

} 



}

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2012-12-21 05:19:55 thavasidurai

此平移手勢識別器操作有什麼問題？

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