iphone - 需要左值作为赋值的左操作数

Question

您好，我在 xcode 中收到“需要左值作为赋值的左操作数”错误。为什么？这是我的代码(window1/2 是 UIViewController):

- (void)loadView
{

    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0,0,320,460)];
    UIView *contentView = [[UIView alloc] initWithFrame:CGRectMake(0,0,640,460)];


    self.window1 = [TweetViewController alloc];
    self.window2 = [InfoViewController alloc];


    [contentView addSubview:self.window1.view];
    self.window2.view.frame.origin.x = 320; //HERE IS THE ERROR!!
    [contentView addSubview:self.window2.view];


    [scrollView addSubview:contentView];
    scrollView.contentSize = contentView.frame.size;


    scrollView.pagingEnabled = YES;


    self.view = scrollView;


    [contentView release];
    [scrollView release];
}

感谢您的帮助。

Answer 1

self.window2.view.frame 部分将留给您一个 getter，而不是真正进入并抓取 内部框架 CGRect .您需要做的是让 CGRect 更改它，然后将其重新设置到 View 中。

CGRect f = self.window2.view.frame; // calls the getter
f.origin.x = 320;
self.window2.view.frame = f; // calls the setter