objective-c - 在 objective-c 中将一个图像放在另一个图像之上用于按钮

Question

我想在另一张图片上显示一张图片。基本上我试图显示该框已选中。问题是，当单击未选中的图像时，会出现复选按钮，但复选框会消失。我希望复选符号出现在复选框的顶部。

代码如下所示:

if (ShopCartUnedited) {
            [button setBackgroundImage:[UIImage imageNamed:@"none.png"] forState:UIControlStateNormal];
            [arrOfObjects addObject:@"NO"];
        }
        else {
            if (counter+1 <= nQty) {
                [button setBackgroundImage:[UIImage imageNamed:@"check2.png"] forState:UIControlStateNormal];
                [arrOfObjects addObject:@"YES"];
            }
            else {
                [button setBackgroundImage:[UIImage imageNamed:@"none.png"] forState:UIControlStateNormal];
                [arrOfObjects addObject:@"NO"];
            } 
        }

如果单击时如何更改 check2.png 位于 none.png 之上...

Answer 1

您可以有两张不同的图片，一张有复选标记，另一张没有复选标记，然后在它们之间切换。如果那不可能，您需要在 check2.png

的按钮顶部添加一个单独的 ImageView

//create an imageview and add on button, adjust the frame as required.
[button addSubview:imageview];
imageview.userInteractionEnabled = NO;//if button is not accepting the touches
[button setBackgroundImage:[UIImage imageNamed:@"none.png"] forState:UIControlStateNormal];

        if (ShopCartUnedited) {
            [imageview setImage:nil];
            [arrOfObjects addObject:@"NO"];
        }
        else {
            if (counter+1 <= nQty) {
                [imageview setImage:[UIImage imageNamed:@"check2.png"]];
                [arrOfObjects addObject:@"YES"];
            }
            else {
                [imageview setImage:nil];
                [arrOfObjects addObject:@"NO"];
            } 
        }

或者代替这个 if-else block ，只使用

        if ((ShopCartUnedited) || (counter+1 > nQty)) {
            [imageview setImage:nil];
            [arrOfObjects addObject:@"NO"];
        } else {
             [imageview setImage:[UIImage imageNamed:@"check2.png"]];
             [arrOfObjects addObject:@"YES"];              
        }