ios 导航栏怎么添加左右按钮

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"LeftBarButton" style:UIBarButtonItemStylePlain target:self action:@selector(tapLeftBarButtonItem)]

self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"RightBarButton" style:UIBarButtonItemStylePlain target:self action:@selector(tapRightBarButtonItem)]

见代码

UIButton *btn=[UIButton buttonWithType:UIButtonTypeCustom]

btn.frame = CGRectMake(0, 0, 44, 44)

btn.adjustsImageWhenHighlighted = NO

[btn setImage:[UIImage imageNamed:imageName] forState:UIControlStateNormal]

[btn addTarget:self action:Action forControlEvents:UIControlEventTouchUpInside]

UIBarButtonItem *item=[[UIBarButtonItem alloc]initWithCustomView:btn]

UIBarButtonItem *negativeSpacer = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil]

negativeSpacer.width = -12//ios7以后右边距默认值18px，负数相当于右移，正数左移

self.navigationItem.leftBarButtonItems=@[negativeSpacer,item]

左右按钮一般用来实现回到上一页，和去下一页的功能。这一般由pop，push方法完成，这个方法在UINavigationContoller中，重名字可以知道，这是个视图控制器，简而言之是个容器。管理页面间的跳转。它上面有toolbar，和navigationBar。

先看下navigationbar的构成，navigationBar中包含了这几个重要组成部分：leftBarButtonItem, rightBarButtonItem, backBarButtonItem, title。

下面是代码

UIButton* leftBtn= [UIButton buttonWithType:UIButtonTypeCustom]

[leftBtn setImage:[UIImage imageNamed:@"设置按钮"] forState:UIControlStateNormal]

leftBtn.frame = CGRectMake(0, 0, 30, 30)

UIBarButtonItem* leftBtnItem = [[UIBarButtonItem alloc]initWithCustomView:pCenter]

[leftBtn addTarget:self action:@selector(setviewinfo) forControlEvents:UIControlEventTouchUpInside]

[self.navigationItem setleftBarButtonItem:leftBtnItem]、

我做的是右边按钮，想做左边修改[self.navigationItem setleftBarButtonItem:leftBtnItem]为[self.navigationItem setRightBarButtonItem:leftBtnItem]

再点击事件里可以做一些push，pop等跳转页面 *** 作。

button在最上面，item在button下，navigationbar在item下，是有层次关系的。

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