我应该在我的NSCell上调用什么方法

问题描述

我使用自定义NSCell编写了一个自定义NSControl。它是一个控件，所以它必须响应鼠标。我创建了一个NSTrackingArea在我的控制，实现 -mouseEntered：， -mouseExited：和 mouseMoved：。 （我必须实现 -mouseUp / Down：，但我不知道在那里做什么，所以现在我没有重写这些方法）。在这些方法中，我成功地确定了鼠标当前是在哪个单元格。现在我有两个问题：

• 这是跟踪鼠标的好方法吗？


• 当鼠标进入单元格时，当鼠标离开单元格等时，我应该在鼠标单击时调用NSCell的方法是什么？




所以，基本上：我应该什么时候调用NSCell上的什么方法让我们它会响应鼠标事件？





EDIT：

重新读取文档， NSCell的 -trackMouse：inRect：ofView：untilMouseUp：并覆写 -startTrackingAt：inView：， -continueTracking：at：inView：和 -stopTracking：at：inView：mouseIsUp：。再两个问题：1）文档给的印象这些只有当鼠标下来时才调用。那是对的吗？那么我该怎么办呢？ 2）在哪里/何时应该调用NSCell的 -trackMouse：inRect：ofView：untilMouseUp：？

解决方案

我最终实现了自己的鼠标跟踪机制：

  // MyControl.m：
 
  - （void）mouseDown：（NSEvent *）theEvent {
 int currentCellIndex = [self indexOfCellAtPoint：[self convertPoint：[theEvent locationInWindow] fromView：nil]]; 
 if（currentCellIndex< [cell count]）{
 MKListCell * cell = [cells objectAtIndex：currentCellIndex]; 
 currentCell = cell; 
 [currentCell mouseDown：theEvent]; 
} 
} 
 
  - （void）mouseUp：（NSEvent *）theEvent {
 int currentCellIndex = [self indexOfCellAtPoint：[self convertPoint：[theEvent locationInWindow] fromView ：零]]; 
 if（currentCellIndex< [cell count]）{
 MKListCell * cell = [cell objectAtIndex：currentCellIndex]; 
 [mouseUp：theEvent]; 
} 
} 
 
  - （void）mouseEntered：（NSEvent *）theEvent {
 int currentCellIndex = [self indexOfCellAtPoint：[self convertPoint：[theEvent locationInWindow] fromView ：零]]; 
 if（currentCellIndex< [cell count]）{
 MKListCell * cell = [cell objectAtIndex：currentCellIndex]; 
 currentCell = cell; 
 [currentCell mouseEntered：theEvent]; 
} 
} 
 
  - （void）mouseExited：（NSEvent *）theEvent {
 int currentCellIndex = [self indexOfCellAtPoint：[self convertPoint：[theEvent locationInWindow] fromView ：零]]; 
 if（currentCellIndex< [cell count]）{
 MKListCell * cell = [cell objectAtIndex：currentCellIndex]; 
 [cell mouseExited：theEvent]; 
 currentCell = nil; 
} 
} 
 
  - （void）mouseMoved：（NSEvent *）theEvent {
 int currentCellIndex = [self indexOfCellAtPoint：[self convertPoint：[theEvent locationInWindow] fromView ：零]]; 
 MKListCell * cell; 
 if（currentCellIndex< [cell count]）{
 cell = [cell objectAtIndex：currentCellIndex]; 
} 
 if（currentCell！= cell）{
 [currentCell mouseExited：theEvent]; 
 [cell mouseEntered：theEvent]; 
 currentCell = cell; 
} 
 else {
 [currentCell mouseMoved：theEvent]; 
} 
} 
 
  - （void）mouseDragged：（NSEvent *）theEvent {
 int currentCellIndex = [self indexOfCellAtPoint：[self convertPoint：[theEvent locationInWindow] fromView ：零]]; 
 MKListCell * cell = nil; 
 if（currentCellIndex< [cell count]）{
 cell = [cell objectAtIndex：currentCellIndex]; 
} 
 if（currentCell！= cell）{
 [currentCell mouseExited：theEvent]; 
 [cell mouseEntered：theEvent]; 
 currentCell = cell; 
} 
 else {
 [currentCell mouseMoved：theEvent]; 
} 
} 
 
  - （int）indexOfCellAtPoint：（NSPoint）p {
 int cellIndex =（self.bounds.size.height  -  p.y）/ cellHeight; 
 return cellIndex; 
} 
  

当然，在 MyCell.h ：

   - （void）mouseDown：（NSEvent *）event; 
  - （void）mouseUp：（NSEvent *）event; 
  - （void）mouseMoved：（NSEvent *）event; 
  - （void）mouseEntered：（NSEvent *）event; 
  - （void）mouseExited：（NSEvent *）event; 
  

使用这些方法的空实现（因此编译器不会抱怨，的鼠标处理方法子类化）。




I am writing a custom NSControl with custom NSCells. It is a control, so it has to respond to the mouse. I created an NSTrackingArea over my control, implemented -mouseEntered:, -mouseExited: and -mouseMoved:. (And I will have to implement -mouseUp/Down:, but I have no idea what to do in there, so for now I haven't overridden those methods yet.) In these methods I successfully determine on which cell the mouse currently is. Now I have two questions:

• Is this a good approach for tracking the mouse? If not, what should I do instead?
• What method should I call on my NSCell on a mouse click, when the mouse enters the cell, when the mouse leaves the cell etc? Apple's docs are not very clear about this.

So, basically: When should I call what method on my NSCell to let it respond to mouse events?

EDIT:
Rereading the docs, I think I should call NSCell's -trackMouse:inRect:ofView:untilMouseUp: and override -startTrackingAt:inView:, -continueTracking:at:inView: and -stopTracking:at:inView:mouseIsUp:. Again two questions: 1) the docs give the impression these are only called when the mouse is down. Is that correct? Then what should I do instead? 2) Where/when should I call NSCell's -trackMouse:inRect:ofView:untilMouseUp:?

解决方案

I ended up implementing my own mouse tracking mechanism:

// MyControl.m:

- (void)mouseDown:(NSEvent *)theEvent {
    int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
    if (currentCellIndex < [cells count]) {
        MKListCell *cell = [cells objectAtIndex:currentCellIndex];
        currentCell = cell;
        [currentCell mouseDown:theEvent];
    }
}

- (void)mouseUp:(NSEvent *)theEvent {
    int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
    if (currentCellIndex < [cells count]) {
        MKListCell *cell = [cells objectAtIndex:currentCellIndex];
        [cell mouseUp:theEvent];
    }
}

- (void)mouseEntered:(NSEvent *)theEvent {
    int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
    if (currentCellIndex < [cells count]) {
        MKListCell *cell = [cells objectAtIndex:currentCellIndex];
        currentCell = cell;
        [currentCell mouseEntered:theEvent];
    }
}

- (void)mouseExited:(NSEvent *)theEvent {
    int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
    if (currentCellIndex < [cells count]) {
        MKListCell *cell = [cells objectAtIndex:currentCellIndex];
        [cell mouseExited:theEvent];
        currentCell = nil;
    }
}

- (void)mouseMoved:(NSEvent *)theEvent {
    int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
    MKListCell *cell;
    if (currentCellIndex < [cells count]) {
        cell = [cells objectAtIndex:currentCellIndex];
    }
    if (currentCell != cell) {
        [currentCell mouseExited:theEvent];
        [cell mouseEntered:theEvent];
        currentCell = cell;
    }
    else {
        [currentCell mouseMoved:theEvent];
    }
}

- (void)mouseDragged:(NSEvent *)theEvent {
    int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
    MKListCell *cell = nil;
    if (currentCellIndex < [cells count]) {
        cell = [cells objectAtIndex:currentCellIndex];
    }
    if (currentCell != cell) {
        [currentCell mouseExited:theEvent];
        [cell mouseEntered:theEvent];
        currentCell = cell;
    }
    else {
        [currentCell mouseMoved:theEvent];
    }
}

- (int)indexOfCellAtPoint:(NSPoint)p {
    int cellIndex = (self.bounds.size.height - p.y) / cellHeight;
    return cellIndex;
}

And of course, in MyCell.h:

- (void)mouseDown:(NSEvent *)event;
- (void)mouseUp:(NSEvent *)event;
- (void)mouseMoved:(NSEvent *)event;
- (void)mouseEntered:(NSEvent *)event;
- (void)mouseExited:(NSEvent *)event;

With an empty implementation for those methods (so the compiler doesn't complain and I can leave the implementation of the mouse handling methods to subclasses).

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