iOS开发~UITextView光标不在起始位置问题

问题：当用UITextView展示超出屏幕的文本内容时，并且禁止了其编辑功能，发现打开页面后，光标不在开头位置，而是在屏幕中间

解决办法：

- (void) viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    
    self.contentTextView.editable = NO;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    self.contentTextView.attributedText = attributedString;
    self.contentTextView.editable = YES;
    [self.contentTextView becomeFirstResponder];
    self.contentTextView.selectedRange = NSMakeRange(0,0);
    self.contentTextView.tintColor = [UIColor clearColor];
}