ios - 如何获得 UITableView 单元格中 UIButton 的绝对 x,y

Question

在 cellForRowAtIndexPath() 中，我在单元格中分配了一个 UIButton。按下按钮时，调用委托(delegate)需要在屏幕上与按钮相同的绝对位置分配一个 UIImageView，以便开始将 UIImageView 拖动到屏幕上的其他位置

但是，当我读取委托(delegate)的“发送者”(UIButton)的 x,y 时，y 是单元格内 UIButton 的相对 y，而不是 iPad 屏幕上 UIButton 的 y。

在委托(delegate)中，如何获得在 UITableView 的单元格中分配的 UIButton 的绝对屏幕 x、y？

在 cellForRowAtIndexPath() 中创建 UIBUTTON 的代码......................................

                    // Put invisible UIButton on top of device icon, to detect start of drag:                    !!!
                    UIButton* invisible_drag_button = [UIButton buttonWithType:UIButtonTypeCustom];
                    invisible_drag_button.frame = CGRectMake    (x,y, w,h);        // location and size of device off icon
                    invisible_drag_button.tag = cell_record_index;      // store user device's record index
                    printf("%d  = invisible_drag_button.tag     aaaaaaaaaaaaaaaaa   \n", PWR_RX_status_index ); // !!!
                    printf("x=%d y=%d w=%d h=%d \n", x,y,w,h ); // !!!
                    [invisible_drag_button addTarget: self 
                                action:@selector( delegate_drag_start: )
                                forControlEvents: UIControlEventTouchDown ];
                    [cell.contentView addSubview: invisible_drag_button ];

响应按钮按下的代表......................

-(void)delegate_drag_start: (id)sender

{ int drag_record_index;//拖拽设备的数据库记录索引

// Drag record index = database index of device:
    UIButton* invisible_drag_button = (UIButton*)sender;
    drag_record_index = invisible_drag_button.tag;      

printf("delegate_drag_start for drag_record_index %d.   \n", drag_record_index  );

// Lookup drag device's type from its record:
    int device_type = area_device_status[ device_area ][ drag_record_index ].device_type;

// Init UIImageView of drag device image:
    // Lookup its UIImage from its type, and allocate UIImageView of drag device image:
    self.device_drag_UIImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed: device_image_filename( device_type )]];

    self.device_drag_UIImageView.userInteractionEnabled = YES;
    // Get screen location of touched device icon image:
        CGRect drag_button_frame = [invisible_drag_button frame];
        //CGPoint drag_button_location = CGPointMake(invisible_drag_button.frame.origin.x, invisible_drag_button.frame.origin.y);

                    printf("x=%d y=%d w=%d h=%d \n",    (int)drag_button_frame.origin.x, 
                                                        (int)drag_button_frame.origin.y, 
                                                        (int)drag_button_frame.size.width, 
                                                        (int)drag_button_frame.size.height  ); // !!!

            // Start drag image at same location as touched device image:
            self.device_drag_UIImageView.frame = CGRectMake(    drag_button_frame.origin.x, 
                                                                drag_button_frame.origin.y, 
                                                                drag_button_frame.size.width * DRAG_IMAGE_BIGGER_FACTOR, 
                                                                drag_button_frame.size.height * DRAG_IMAGE_BIGGER_FACTOR );

    [self.view addSubview: self.device_drag_UIImageView];
    [self.view bringSubviewToFront: self.device_drag_UIImageView];

Answer 1

试试这个:

[view convertPoint:pointToConvert toView:nil]

它将一个点从接收者的坐标系转换到指定 View 的坐标系。如果第二个参数为 nil，则转换为窗口坐标系。