iOS创建navigationItem图片拉伸变形问题

创建自定义的rightBarButtonItem图片变形,可以使用以下方法:

[button.widthAnchor constraintEqualToConstant:40].active = YES;

 [button.heightAnchor constraintEqualToConstant:40].active = YES;

- (void)createCustomBtn{

    UIButton*button = [[UIButtonalloc]initWithFrame:CGRectMake(0,0,40,40)];

    [buttonsetImageEdgeInsets:UIEdgeInsetsMake(5, 5, 5, 5)];

    [button.widthAnchor constraintEqualToConstant:40].active = YES;

    [button.heightAnchor constraintEqualToConstant:40].active = YES;

    [buttonsetImage:[UIImage imageNamed:@"add_device"] forState:UIControlStateNormal];

    [buttonaddTarget:self action:@selector(addButtonEvent) forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem*addBarButton = [[UIBarButtonItemalloc]initWithCustomView:button];

    self.navigationItem.rightBarButtonItem = addBarButton;

}