iOS 14中長(zhǎng)按返回按鈕會(huì)顯示多級(jí)菜單，滑動(dòng)后可以返回對(duì)應(yīng)的頁(yè)面。

navigation stack.gif

在App上長(zhǎng)按后title為空

空白.png

backButtonDisplayMode

iOS 14新增了一個(gè)屬性backButtonDisplayMode來(lái)定義title的來(lái)源

typedef NS_ENUM(NSInteger, UINavigationItemBackButtonDisplayMode) {
    /// Default mode, uses an appropriate title, followed by a generic title (typically 'Back'), then no title.
    UINavigationItemBackButtonDisplayModeDefault = 0,
    /// Generic titles only. Ignores .title and .backButtonTitle (but *not* .backBarButtonItem.title).
    UINavigationItemBackButtonDisplayModeGeneric = 1,
    /// Don't use a title, just the back button indicator image.
    UINavigationItemBackButtonDisplayModeMinimal = 2,
} NS_SWIFT_NAME(UINavigationItem.BackButtonDisplayMode);

title來(lái)源的優(yōu)先級(jí)
1.navigationItem.backBarButtonItem
2.navigationItem.backButtonTitle
3.navigationItem.title和viewController的title，同時(shí)設(shè)置顯示為viewController的title

App中使用

UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
self.navigationItem.backBarButtonItem = item;

來(lái)隱藏返回按鈕的標(biāo)題，引起了上面的問(wèn)題。

UINavigationItemBackButtonDisplayModeMinimal

Minimal模式下，返回按鈕不顯示title，但是 navigation stack可以顯示出 title,未設(shè)置title的時(shí)候顯示返回。

適配

    if (@available(iOS 14.0, *)) {
        self.navigationItem.backButtonDisplayMode = UINavigationItemBackButtonDisplayModeMinimal;
    } else {
        UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
        self.navigationItem.backBarButtonItem = item;
    }

適配.png