AVPlayerViewController的使用、使用Masonry水平/垂直方向多元素布局、UIGestureRecognizer知识点总结

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AVPlayerVIewController使用

1. @property (nonatomic,strong) AVPlayerViewController* playerVC;
   -------------------------------------------------------------------
   self.playerVC = [[AVPlayerViewController alloc]init];
   //设置播放源
   self.playerVC.player = [[AVPlayer alloc]initWithURL:[NSURL URLWithString:@"http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4"]];
   /*
   设置视频播放的模式
     AVLayerVideoGravityResizeAspectFill等比例铺满，宽或高有可能出屏幕
     AVLayerVideoGravityResizeAspect 等比例  默认
     AVLayerVideoGravityResize 完全适应宽高
   */
   self.playerVC.videoGravity = AVLayerVideoGravityResizeAspectFill;
   //将AVPlayerViewController作为子视图控制器
   [self addChildViewController:self.playerVC];
   //设置子视图控制器位置及大小
   self.playerVC.view.frame = CGRectMake(0, 88, self.view.frame.size.width, self.view.frame.size.height/3);
   //添加到视图上
   [self.view addSubview:self.playerVC.view];
   

使用Masonry进行水平/垂直方法多元素布局

//在数组中添加四个视图元素
for (NSInteger i=0; i<4; i++) {
  HYCardViewItem* item = [[HYCardViewItem alloc]initWithFrame:CGRectMake(0, 0, 50, 77)];
  ...
  [_cardView addSubview:item];
  [carViewArr addObject:item];
}
//使用masonry的distributeViewsAlongAxis进行水平布局，这里是设置固定元素大小的，还有一种是设置固定间距的为withFixedSpacing,同样可以设置Axis参数为Vertical，可以在纵向进行布局
[carViewArr mas_distributeViewsAlongAxis:MASAxisTypeHorizontal withFixedItemLength:50.f leadSpacing:22.f tailSpacing:22.f];
[carViewArr mas_makeConstraints:^(MASConstraintMaker *make) {
  make.top.equalTo(_cardView.mas_top).offset(48);
}];

UIGestureRecognizer 手势识别总结

• UITapGestureRecognizer点按手势

  • //创建点按手势
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap:)];
    //手势也可以设置代理
    tapGesture.delegate = self;
    //添加手势
    [self.imageView addGestureRecognizer:tapGesture];
    }
    //设置手势的响应方法
    - (void)tap:(UITapGestureRecognizer*)tapGesture{
    }
    -------------------------------------------------
    //代理方法，可以根据触摸的位置来决定是否接受该手势
      - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
      
    }
    

• UITapGestureRecognizer长按手势

  • UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)];
    [self.imageView addGestureRecognizer:longPressGesture];
    //响应方法
    - (void)longP:(UILongPressGestureRecognizer *)longPress {
        //判断长按时的状态,根据手势状态的改变做出响应的调整
        if (longPress.state == UIGestureRecognizerStateBegan) {
        }else if (longPress.state == UIGestureRecognizerStateChanged) {
        }else if (longPress.state == UIGestureRecognizerStateEnded) {
        }
    }
    

• UIPanGestureRecognizer平移手势/拖拽手势

  • //根据手势的偏移量，改变图片的位置
    UIPanGestureRecognizer *panGes = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
    [self.imageView addGestureRecognizer:panGes];
    
    - (void)pan:(UIPanGestureRecognizer *)pan {
      //获取偏移量
      CGPoint transP = [pan translationInView:self.imageView];
      NSLog(@"transP = %@", NSStringFromCGPoint(transP));
    
      //移动图片
      self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, transP.x, transP.y);
      //清零,不要累加
      [pan setTranslation:CGPointZero inView:self.imageView];
    }
    

• UISwipeGestureRecognizer轻扫手势

• UIRotationGestureRecognizer旋转手势

• UIPinchGestureRecognizer捏合手势

2. 手势的几种代理方法

   • 以下方法均需要设置手势的代理,并遵守UIGestureRecognizerDelegate协议

     tapGesture.delegate = self
     

   • 如果一个手势A的识别部分是另一个手势B的子部分时，默认情况下A就会先识别，B就无法识别了。我们可以指定某个手势执行的前提是另一个手势失败才会识别执行，这样控制手势识别的响应顺序。

     - (void)requireGestureRecognizerToFail:(UIGestureRecognizer *)otherGestureRecognizer;
     

   • 如果同一视图需要一次响应多个手势操作,可以实现下面的UIGestureRecognizerDelegate的代理方法，当返回YES的时候，可以同时响应多个手势。

     - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer;
     

   • 父视图如果有手势需要识别，子视图同样有相似触摸事件需要处理，这时候就可能产生冲突。

     //判断touch.view的类型
     - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
       if ([touch.view isKindOfClass:[UITableView class]]) {
         return NO;
       }
       if ([NSStringFromClass([touch.view class]) isEqualToString:@"UITableViewCellContentView"]) {
         return NO;
       }
     }
     

3. 手势与响应者链

   • 手势与响应者链有一些差别，触摸事件首先会传递到手势上，如果手势识别成功，就会取消事件的继续传递。如果手势识别失败，事件才会被响应链处理

   • 对于 UIButton，UISwitch，UISegmentedControl，UIStepper、UIPageControl 进行单击操作，如果父视图有轻敲手势需要识别，依然会按照响应链来处理，先响应这些控件的单击事件，这仅适用于与控件的默认操作重叠的手势识别。

   • 如果子视图和父视图都有手势需要识别，则按照firstResponder从子视图到父视图传递。