iphone - 每次单击 iPhone 中的按钮都会更改 View 的背景颜色

Question

-(IBAction) changeColOnClick:(id)sender
{
    NSArray *colors = [NSArray arrayWithObjects:@"[UIColor brownColor]",@"[UIColor blackColor]",@"[UI greenColor]",@"[UIColor redColor]", nil];

    self.view.backgroundColor = [colors objectAtIndex:i];
    // ERROR::changebackground[1089:207] -[NSCFString CGColor]: unrecognized selector sent to instance 0x357c

    //label.text = [colors objectAtIndex:i]; //i is defined in the implementation
    i++;

    if(i==[colors count]-1)
    {
        i=0;
    }
}

Answer 1

像这样修改你的代码。它会起作用

-(IBAction) changeColOnClick:(id)sender
{
    NSArray *colors = [NSArray arrayWithObjects:[UIColor brownColor],[UIColor blackColor],[UI greenColor],[UIColor redColor], nil];

    self.view.backgroundColor = [colors objectAtIndex:i];
    //label.text = [colors objectAtIndex:i]; //i is defined in the implementation
    i++;

    if(i==[colors count]-1)
    {
        i=0;
    }
 }