Question

我正在使用自定义NSCell编写自定义NSControl。它是一个控件，所以它必须响应鼠标。我在我的控件上创建了一个NSTrackingArea，实现了-mouseEntered:，-mouseExited:和-mouseMoved:。（而且我必须实现-mouseUp/Down:，但我不知道该怎么做，所以现在我还没有覆盖那些方法。）在这些方法中，我成功地确定鼠标当前是哪个单元格。现在我有两个问题：

这是跟踪鼠标的好方法吗？如果没有，我该怎么做呢？
当鼠标进入细胞，当鼠标离开细胞等时，我应该用什么方法在鼠标点击时调用我的NSCell？ Apple的文档对此并不十分清楚。

所以，基本上：我什么时候应该在我的NSCell上调用哪种方法让它响应鼠标事件？

修改
重读文档，我想我应该调用NSCell的-trackMouse:inRect:ofView:untilMouseUp:并覆盖-startTrackingAt:inView:，-continueTracking:at:inView:和-stopTracking:at:inView:mouseIsUp:。还有两个问题：1）文档给人的印象这些仅在鼠标停止时调用。那是对的吗？那我该怎么做呢？ 2）我应该在何时/何时致电NSCell的-trackMouse:inRect:ofView:untilMouseUp:？

Answer 1

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 < [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;
}

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;

对这些方法使用空实现（因此编译器不会抱怨，我可以将鼠标处理方法的实现留给子类）。

我应该在NSCell上调用什么方法

1 个答案: