今天mark一下navgationbar的知識，有時候我們項目需要做像網(wǎng)易云音樂那樣的navgationbar，有多個item同在右邊或者左邊玩耍。

見效果圖，這個是我們要實現(xiàn)的。

navgationbar.png

為了幫助大家學(xué)習(xí)，我先說下曲線救國的兩種方法。也是我爬過的坑。共勉。

• 我嘗試了三種方法，一種是用toolbar放在navgationBar.rightBarButtonItem上

- (void)initNav{

    /* CREATE BOOKMARKS BUTTON */
    UIButton *bookmarksButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, kBookmarksImage.size.width, kBookmarksImage.size.height)];
    bookmarksButton.backgroundColor = [UIColor greenColor];
    [bookmarksButton setImage:kBookmarksImage forState:UIControlStateNormal];
    [bookmarksButton addTarget:self action:@selector(toolbarButtonTapped:) forControlEvents:UIControlEventTouchDown];
    bookmarksButton.tag = 1;
    
    UIBarButtonItem *bookmarksButtonItem = [[UIBarButtonItem alloc] initWithCustomView:bookmarksButton];
    
    UIBarButtonItem *spacer = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    spacer.width = SPACE_BETWEEN_BUTTONS;
    
    UIButton *bookmarksButton2 = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, kBookmarksImage.size.width, kBookmarksImage.size.height)];
    bookmarksButton2.backgroundColor = [UIColor orangeColor];
    [bookmarksButton2 setImage:kBookmarksImage forState:UIControlStateNormal];
    [bookmarksButton2 addTarget:self action:@selector(toolbarButtonTapped:) forControlEvents:UIControlEventTouchDown];
    bookmarksButton2.tag = 2;
    
    UIBarButtonItem *bookmarksButtonItem2 = [[UIBarButtonItem alloc] initWithCustomView:bookmarksButton2];
    
    NSMutableArray<UIBarButtonItem*>*buttons = [NSMutableArray array];
    [buttons addObjectsFromArray:@[bookmarksButtonItem,spacer,bookmarksButtonItem2]];
    
    
    /* ADD ALL THESE BUTTONS TO CUSTOM TOOLBAR AND TOOLBAR TO NAVIGATION BAR */
    UIToolbar *customToolbar = [[UIToolbar alloc]
                                initWithFrame:CGRectMake(0.0f, 0.0f, 50, 44.01f)]; // 44.01 shifts it up 1px for some reason
    customToolbar.backgroundColor = [UIColor redColor];
    customToolbar.clearsContextBeforeDrawing = NO;
    customToolbar.clipsToBounds = NO;
    customToolbar.tintColor = [UIColor colorWithWhite:0.305f alpha:0.0f]; // closest I could get by eye to black, translucent style.
    customToolbar.barStyle = -1; // clear background
    [customToolbar setItems: buttons animated:NO];
    
    UIBarButtonItem *customUIBarButtonitem = [[UIBarButtonItem alloc] initWithCustomView:customToolbar];
    self.navigationItem.rightBarButtonItem = customUIBarButtonitem;
}

效果是這樣的

error.png

紫色區(qū)和黃色區(qū)是我們無法改變的，我當(dāng)時以為這是最接近神的操作了，然而失敗了。

• 還有一種是用自定義view實現(xiàn)，效果雖然如出一轍，賊繁瑣，需要重寫btn還需要將view加載到navgationbar上面，因為原始的navgationbar的背景色是漸變色，那么此時問題來了，我右滑返回上級viewcontroller，自定義view并未消失而，你需要讓它消失你要做很多臟活。不痛快

重頭戲來了，原諒我說了那么多廢話

上代碼

- (void)initNavBar{
    // 需要注意為什么兩個btn point都是（0，0）因為設(shè)置frame只能控制按鈕的大小
    UIButton *searchBtn = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 22, 22)];
    [searchBtn setImage:[UIImage imageNamed:@"spotsupervision_playback_searchbtn"] forState:UIControlStateNormal];
    [searchBtn addTarget:self action:@selector(toolbarButtonTapped:) forControlEvents:UIControlEventTouchDown];
    searchBtn.tag = 1;
    
    UIButton *uploadBtn = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 22, 22)];
    [uploadBtn setImage:[UIImage imageNamed:@"spotsupervision_playback_uploadbtn"] forState:UIControlStateNormal];
    [uploadBtn addTarget:self action:@selector(toolbarButtonTapped:) forControlEvents:UIControlEventTouchDown];
    uploadBtn.tag = 2;
    
    UIBarButtonItem *btn_search = [[UIBarButtonItem alloc] initWithCustomView:searchBtn];
    UIBarButtonItem *btn_upload = [[UIBarButtonItem alloc] initWithCustomView:uploadBtn];
    
    UIBarButtonItem *negativeRightSpacer = [[UIBarButtonItem alloc]
                                       
                                       initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace
                                       
                                       target:nil action:nil];
    
    /**
     *  width為負(fù)數(shù)時，相當(dāng)于btn向右移動width數(shù)值個像素，由于按鈕本身和邊界間距為5pix，所以width設(shè)為-5時，間距正好調(diào)整
     *  為0；width為正數(shù)時，正好相反，相當(dāng)于往左移動width數(shù)值個像素
     */
    negativeRightSpacer.width = -5;
    
    UIBarButtonItem *negativeMidSpacer = [[UIBarButtonItem alloc]
                                        
                                        initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace
                                        
                                        target:nil action:nil];
    
    negativeMidSpacer.width = 10;
    
    self.navigationItem.rightBarButtonItems = [NSArray arrayWithObjects:negativeRightSpacer, btn_upload, negativeMidSpacer, btn_search, nil];
    
    
}

不解釋一切盡在代碼中。