objective-c - 可拖动的 NSView

Question

如何以编程方式创建 NSView 以便用户可以用鼠标移动其位置？我需要为 View 分配哪些属性？谢谢!

    newView = [helpWindow contentView];
    [contentView addSubview:newView];
    //add properties of newView to be able to respond to touch and can be draggable

Answer 1

不幸的是，没有像 setMoveByWindowBackground: 这样的简单方法可以对窗口进行操作。您必须重写 mouseDown:、mouseDragged: 和 mouseUp: 并根据鼠标指针的位置使用 setFrameOrigin:。为了在您首次单击 View 内部时不发生 View 跳转，您还需要考虑 View 原点与首次单击时鼠标指针在 View 中的位置之间的偏移量。这是我在一个项目中制作的一个示例，用于在父 View 中移动“图 block ”(这是游戏“Upwords”的计算机版本，类似于 3d 拼字游戏)。

-(void)mouseDown:(NSEvent *) theEvent{
    self.mouseLoc = [theEvent locationInWindow];
    self.movingTile = [self hitTest:self.mouseLoc]; //returns the object clicked on
    int tagID = self.movingTile.tag;
    if (tagID > 0 && tagID < 8) {
        [self.viewsList exchangeObjectAtIndex:[self.viewsList indexOfObject:self.movingTile] withObjectAtIndex: 20]; // 20 is the highest index in the array in this case
        [self setSubviews:self.viewsList]; //Reorder's the subviews so the picked up tile always appears on top
        self.hit = 1;
        NSPoint cLoc = [self.movingTile convertPoint:self.mouseLoc fromView:nil];
        NSPoint loc = NSMakePoint(self.mouseLoc.x - cLoc.x, self.mouseLoc.y - cLoc.y);
        [self.movingTile setFrameOrigin:loc];
        self.kX = cLoc.x;  //this is the x offset between where the mouse was clicked and "movingTile's" x origin
        self.kY = cLoc.y;  //this is the y offset between where the mouse was clicked and "movingTile's" y origin
    }
}

-(void)mouseDragged:(NSEvent *)theEvent {
    if (self.hit == 1) {
        self.mouseLoc = [theEvent locationInWindow];
        NSPoint newLoc = NSMakePoint(self.mouseLoc.x - self.kX, self.mouseLoc.y - self.kY);
        [self.movingTile setFrameOrigin:newLoc];
    }
}

这个例子指出了另一种可能的复杂情况。当您移动 View 时，它可能会出现在其他 View 下方移动，因此我负责将移动 View 设为父 View subview 的最顶层 View (viewsList 是从 self.subviews 获取的数组)