移動時移動多個框架的正確方法

Question

我想知道在從a點移動到b點的過程中，這是否正確地爲遊戲角色製作動畫，同時顯示模擬人物移動的不同動態圖像。

這裏是什麼，我做了一個persudo代碼：

[UIView animateWithDuration:dMAN_MOVEMENT_SPEED/3 animations:^{ 
      //Set Target Image 
      //Set target position 
    }completion:^(BOOL finished){ 
     //2nd to 3rd Frame 
     [UIView animateWithDuration:dMAN_MOVEMENT_SPEED/3 animations:^{ 
      //Set Target Image 
      //Set target position 
     }completion:^(BOOL finished){ 
      //3rd to final Frame 
      [UIView animateWithDuration:dMAN_MOVEMENT_SPEED/3 animations:^{ 
       //Set Target Image 
       //Set target position 
      }completion:^(BOOL finished){ 
       //do nothing 
      }]; 
     }]; 
    }]; 

這是正確的方法是什麼？我這樣做是因爲我可以控制每個幀和每個幀的持續時間。

Answer 1

似乎有可能會有更好的方法。如果你沒有太多的圖像，我可能只是建議使用的UIImageViewanimationImages屬性，然後startAnimating：

NSArray *images = @[[UIImage imageNamed:@"0.jpg"], 
        [UIImage imageNamed:@"1.jpg"], 
        [UIImage imageNamed:@"2.jpg"], 
        [UIImage imageNamed:@"3.jpg"], 
        [UIImage imageNamed:@"4.jpg"], 
        [UIImage imageNamed:@"5.jpg"], 
        [UIImage imageNamed:@"6.jpg"], 
        [UIImage imageNamed:@"7.jpg"]]; 

self.imageView.image = images[0]; 

self.imageView.animationImages = images; 
self.imageView.animationDuration = kAnimationDuration; 
self.imageView.animationRepeatCount = 1; 

[self.imageView startAnimating]; 

[UIView animateWithDuration:kAnimationDuration 
       animations:^{ 
        self.imageView.center = ... // set this to whatever you want 
}]; 

如果您擔心加載所有這一切到內存中，你也可以使用一個CADisplayLink來加載圖像作爲適當的，像下面這樣：

- (void)animateImageUsingDisplayLink 
{ 
    self.imageNames = @[@"0.jpg", 
         @"1.jpg", 
         @"2.jpg", 
         @"3.jpg", 
         @"4.jpg", 
         @"5.jpg", 
         @"6.jpg", 
         @"7.jpg"]; 

    self.imageView.image = [UIImage imageNamed:self.imageNames[0]]; 

    [self startDisplayLink]; 

    [UIView animateWithDuration:kAnimationDuration 
        animations:^{ 
         self.imageView.center = ... // set this to whatever you want 
    }]; 
} 

- (void)startDisplayLink 
{ 
    self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(handleDisplayLink:)]; 
    self.startTime = CACurrentMediaTime(); 
    [self.displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; 
} 

- (void)stopDisplayLink 
{ 
    [self.displayLink invalidate]; 
    self.displayLink = nil; 
} 

- (void)handleDisplayLink:(CADisplayLink *)displayLink 
{ 
    CFTimeInterval elapsed = displayLink.timestamp - self.startTime; 

    // If you want it to repeat, then comment out the following `if` statement 

    if (elapsed >= kAnimationDuration) 
    { 
     [self stopDisplayLink]; 
     return; 
    } 

    NSInteger frameNumber = ((NSInteger) elapsed * [self.imageNames count]/kAnimationDuration) % [self.imageNames count]; 

    if (frameNumber != self.currentFrameNumber) 
    { 
     self.imageView.image = [UIImage imageNamed:self.imageNames[frameNumber]]; 
     self.currentFrameNumber = frameNumber; 
    } 
}