随笔 - iOS自定义返回按钮

博客搬家，2018

在父视图中修改

1、使用 backBarButtonItem 实现，返回按钮紧贴屏幕左边，有返回手势。

这种方法需要将图片设置成 UIImageRenderingModeAlwaysOriginal 模式才能正确显示，否则图片会被渲染成蓝色。

- (void)viewDidLoad {
    [super viewDidLoad];
    UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
    self.navigationController.navigationBar.backIndicatorImage = [[UIImage imageNamed:@"btn_back_black"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    self.navigationController.navigationBar.backIndicatorTransitionMaskImage = [[UIImage imageNamed:@"btn_back_black"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    self.navigationItem.backBarButtonItem = backItem;
}

2、使用 leftBarButtonItem 实现，返回按钮与屏幕左边缘有一小段距离（大概为8），有返回手势。

#import "BaseViewController.h"

@interface BaseViewController ()
@property (nonatomic, strong) UIBarButtonItem *backButtonItem;
@end

@implementation BaseViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.navigationItem.hidesBackButton = YES;
    if (self.navigationController.viewControllers.count > 1) {
        [self backButtonItemImageNamed:@"btn_back_black" target:self action:@selector(backButtonItemClicked:)];
    }
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    //解决根试图左边滑动手势页面卡死问题
    if (self.navigationController.viewControllers.count == 1) {
        self.navigationController.interactivePopGestureRecognizer.enabled = NO;
    } else {
        self.navigationController.interactivePopGestureRecognizer.enabled = YES;
    }
}

- (void)backButtonItemImageNamed:(NSString*)imgName target:(id)target action:(SEL)selector {
    UIImage* backImg = [[UIImage imageNamed:imgName] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    UIBarButtonItem* item = [[UIBarButtonItem alloc] initWithImage:backImg style:UIBarButtonItemStylePlain target:target action:selector];
    self.backButtonItem = item;
    self.navigationItem.leftBarButtonItem = self.backButtonItem;
    //启用返回手势，需要解决卡死问题
    self.navigationController.interactivePopGestureRecognizer.delegate = nil;
}
- (void)backButtonItemClicked:(UIButton *)sender {
    [self.navigationController popViewControllerAnimated:YES];
}

@end

在本视图中修改

1、修改成只有图片的：

UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"箭头left40x40"] style:UIBarButtonItemStylePlain target:self action:@selector(back)];
self.navigationItem.leftBarButtonItem = backItem;

2、修改成只有文字的

UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"返回" style:UIBarButtonItemStylePlain target:self action:@selector(back)];
self.navigationItem.leftBarButtonItem = backItem;

3、自定义文字和图片的：

UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
backButton.frame = CGRectMake(0, 0, 30, 30);
[backButton setTitle:@"返回" forState:UIControlStateNormal];
[backButton setImage:[[UIImage imageNamed:@"箭头left40x40"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal] forState:UIControlStateNormal]
[backButton addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];
self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];

注意：上面这3种方法都会使返回按钮偏右，不大美观；而且会使系统自带的右滑手势返回移除控制的功能失效，解决办法就是在后面添加一句代码，让导航控制器重新设置这个功能，解决代码如下：

self.navigationController.interactivePopGestureRecognizer.delegate = nil;

以上这些方法都是只是在一个视图中生效

全局设置返回按钮

大多数时候自定义返回按钮都是全局一样的，所以全局设置的方法请参考：
iOS 自定义 NavigationController