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简述
iOS的导航支持左滑手势返回上一个界面，这是果粉普遍喜欢的一个特性，iOS7之后的APP适配大多会保留这一特性，慢慢的大多用户已经有了这种操作习惯，对于iPhone的无虚拟键，这种操作也能增加比较友好的用户体验。
在公司新项目之前，没有考虑过多语言RTL的适配方案，开始做的时候UI方面基本实现用一套布局代码支持RTL的两种布局方向。但是真正拿在手里把玩体验时才真切的感受到没有侧滑返回的RTL有多么的不爽。几经查找并没有找到可参考的合适方案，可能国内做多语言适配的技术圈本身就小，适配RTL的就显得更加的稀有了。
希望能帮助到有需要的人，或者有更好的思路可以联系共同探讨。
思路
查不到可参考的资料，只能自己想一想比较合适的方式，恰好在实现一个首页列表跳转详情页时候，解决特殊的转场动画，突然就有了灵感。可能应该有更好的实现方式，现将我的方式展现给大家。
解决方案
-
1、关键词：
UIPercentDrivenInteractiveTransitionfinishInteractiveTransitioncancelInteractiveTransition -
2、关键方法：
updateInteractiveTransition: -
3、实现方式：暂时以文字代码描述，具体可参考之前共享的RTL解决方案，里面有相关源码，末尾处会贴出路径。
具体实现
1、处理navigation代理
使用runtime方式或者基类方式，viewdidappea每次设置nav的代理为自己，viewdiddisappear清空代理(Yoins新版中使用RTL框架中的分类)
- (void)RTL_viewWillAppear:(BOOL)animated
{
[self RTL_viewWillAppear:animated];
self.navigationController.delegate = self;
}
- (void)RTL_viewWillDisappear:(BOOL)animated
{
[self RTL_viewWillDisappear:animated];
if (self.navigationController.delegate == self) {
self.navigationController.delegate = nil;
}
}
2、右滑手势添加
基类初始化时，RTL环境下添加右滑手势，关闭左滑手势，实现最基本的右滑返回。
Navigation 中实现
- (void)RTL_ViewWillAppear:(BOOL)animate
{
// self.view.backgroundColor = [UIColor whiteColor];
// // Do any additional setup after loading the view.
if (![[RTLManager appearance]RTL]) {
self.interactivePopGestureRecognizer.delegate = self;
}
self.interactivePopGestureRecognizer.enabled = ![[RTLManager appearance]RTL];
[self RTL_ViewWillAppear:animate];
}
3、实现手势交互（重点）
基类VC中 增加一个基础属性，保存临时转场上下文
@property (strong ,nonatomic)UIPercentDrivenInteractiveTransition *transitonContext;
在VC右滑动作触发事件中，处理转场动画进度
- (void)handlePanGesture:(UIScreenEdgePanGestureRecognizer *)pan
{
// NSLog(@"_____%zd-----%zd",self.navigationController.childViewControllers.count,self.navigationController.viewControllers.count);
// NSLog(@"----%@",NSStringFromCGPoint([pan translationInView:self.view]));
CGFloat progress = ABS([pan translationInView:self.view].x) / (self.view.bounds.size.width * 1.0);
progress = MIN(1.0, MAX(0.0, progress));
if (pan.state == UIGestureRecognizerStateBegan) {
// 创建过渡对象，弹出viewController
self.transitonContext = [[UIPercentDrivenInteractiveTransition alloc] init];
[self.navigationController popViewControllerAnimated:YES];
}else if (pan.state == UIGestureRecognizerStateChanged) {
// 更新 interactive transition 的进度
[self.transitonContext updateInteractiveTransition:progress];
}else if (pan.state == UIGestureRecognizerStateEnded || pan.state == UIGestureRecognizerStateCancelled) {
// 完成或者取消过渡
if (progress > 0.5) {
[self.transitonContext finishInteractiveTransition];
}
else {
[self.transitonContext cancelInteractiveTransition];
}
self.transitonContext = nil;
}
}
- (id<UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController interactionControllerForAnimationController:(id<UIViewControllerAnimatedTransitioning>)animationController{
if (self.transitonContext) {
return self.transitonContext;
}
else {
return nil;
}
}
最后就是实现自定的各种转场动画了，可以简单模仿系统的滑动切换转场,具体处理在下面VC实现的方法中，返回一个处理转场的实例即可
- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC
4、贴一个简单的动画处理类
@implementation RTLPushAnimation
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext
{
return 0.5;
}
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *container = transitionContext.containerView;
UIView *tmpV = [fromVC.view snapshotViewAfterScreenUpdates:YES];
[container addSubview:toVC.view];
toVC.view.transform = CGAffineTransformMakeTranslation(-toVC.view.bounds.size.width, 0);
[container addSubview:tmpV];
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
tmpV.transform = CGAffineTransformMakeTranslation(toVC.view.bounds.size.width, 0);
toVC.view.transform = CGAffineTransformIdentity;
} completion:^(BOOL finished) {
[tmpV removeFromSuperview];
[transitionContext completeTransition:YES];
}];
}
@end
@implementation RTLPopAnimation
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext
{
return 0.5;
}
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *container = transitionContext.containerView;
UIView *tmpV = [fromVC.view snapshotViewAfterScreenUpdates:YES];
[container addSubview:toVC.view];
toVC.view.transform = CGAffineTransformMakeTranslation(toVC.view.bounds.size.width, 0);
[container addSubview:tmpV];
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
tmpV.transform = CGAffineTransformMakeTranslation(-toVC.view.bounds.size.width, 0);
toVC.view.transform = CGAffineTransformIdentity;
} completion:^(BOOL finished) {
[tmpV removeFromSuperview];
toVC.view.transform = CGAffineTransformIdentity;
[transitionContext completeTransition:!transitionContext.transitionWasCancelled];
}];
}
@end
end
大家或许有更好的处理方案，可以一切探讨下。
新版项目中使用的RTL还在不断地完善中，在公司的公开项目里，有需要可以公开出来。
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