demo功能：ios 美元飄落效果的demo 。

demo說明：美元飄落效果demo ，可以多指觸控，觸控點越多，飄落的美元面額越大。主要代碼在：MainView.m中。

demo截屏：

demo代碼說明：

[csharp]
- (void)onTimer 
{ 
    UIImageView *dollarView; 
    UIImage *dollarImage; 
     
    // for effect... make it harder to get some of the other bill index's  
    // if it does not pass criteria reset back to 1  
     
    // double tap upside down for 5 Dollar bill  
    if(billIndex > 2) { 
        if (deviceTilt.y > 0.5f) 
            billIndex = 5; 
        else 
            billIndex = 1; 
    } 
    else if(billIndex > 1) { 
        if (deviceTilt.x > 0.5f)  
            billIndex = 3; 
        else if (deviceTilt.x < -0.5f) 
            billIndex = 4; 
        else 
            billIndex = 2; 
             
    } 
      
     
    switch (billIndex) { 
        case 2: 
            dollarImage = [UIImage imageNamed:@"dol2.png"]; 
            break; 
        case 3: 
            dollarImage = [UIImage imageNamed:@"5dol.jpg"]; 
            break; 
        case 4: 
            dollarImage = [UIImage imageNamed:@"10dol.jpg"]; 
            break; 
        case 5: 
            dollarImage = [UIImage imageNamed:@"20dol.jpg"]; 
            break;           
        default: 
            dollarImage = [UIImage imageNamed:@"dollar.png"]; 
            break; 
    } 
    //以上是檢測觸點，並分配不同的美元圖片  
    // for effect only draw one 2 dollar bill by resetting billIndex  
    if (billIndex == 2) 
        billIndex = 1; 
    //以下是動畫部分的核心代碼  
    dollarView = [[UIImageView alloc] initWithImage:dollarImage]; 
    int scale = RANDOM_INT(1, 5); 
    int width = 100*scale; 
    int height = 44*scale; 
    if(useEmitterRect) { 
        dollarView.frame = emitterRect; 
    //} else if (deviceTilt.x > 0.5f || deviceTilt.y > 0.5f || deviceTilt.x < -0.5f || deviceTilt.y < -0.5f) {  
    } else if (deviceTilt.y > 0.5f) { 
        dollarView.frame = CGRectMake(160 - (width/2), 490, width, height); 
    } else if (deviceTilt.y < -0.5f) { 
        dollarView.frame = CGRectMake(160 - (width/2), -(height+10), width, height); 
    } else if (deviceTilt.x > 0.5f) { 
        dollarView.frame = CGRectMake(-(width+10), 240-(height/2), width, height); 
    } else if (deviceTilt.x < -0.5f) { 
        dollarView.frame = CGRectMake(330, 240-(height/2), width, height); 
    } else { 
        switch (RANDOM_INT(0, 3)) { 
            case 0: 
                dollarView.frame = CGRectMake(-300, -300, 100*scale, 44*scale); 
                break; 
            case 1: 
                dollarView.frame = CGRectMake(470, -150, 100*scale, 44*scale); 
                break; 
            case 3: 
                dollarView.frame = CGRectMake(470, 630, 100*scale, 44*scale); 
                break;           
            default: 
                dollarView.frame = CGRectMake(-150, 630, 100*scale, 44*scale); 
                break; 
        } 
    } 
     
    [self addSubview:dollarView]; 
    if(helpView) 
        [self bringSubviewToFront:helpView]; 
     
    [UIView beginAnimations:nil context:dollarView]; 
    [UIView setAnimationDuration:2]; 
 
 
    dollarView.frame = CGRectMake(RANDOM_INT(-50, 370), RANDOM_INT(-25, 665), 100, 44); 
         
    int radians = RANDOM_INT(0, 360) * 0.0174532925;         
    [dollarView setTransform:CGAffineTransformMakeRotation(radians)]; 
     
    [UIView setAnimationDelegate:self]; 
    [UIView commitAnimations]; 
     
    billCount++; 
    [billList addObject:dollarView]; 
    if([billList count] >= MAX_BILLS) { 
        UIImageView* oldBill = (UIImageView*)[billList objectAtIndex:0]; 
        [billList removeObjectAtIndex:0]; 
         
        [UIView beginAnimations:nil context:oldBill]; 
         
        [UIView setAnimationDuration:2]; 
        [oldBill setAlpha:0.0]; 
         
        [UIView setAnimationDelegate:self]; 
        [UIView setAnimationDidStopSelector:@selector(goPutThemBack:finished:context:)]; 
        [UIView commitAnimations]; 
    } 
     
} 

- (void)onTimer
{
 UIImageView *dollarView;
 UIImage *dollarImage;
 
 // for effect... make it harder to get some of the other bill index's
 // if it does not pass criteria reset back to 1
 
 // double tap upside down for 5 Dollar bill
 if(billIndex > 2) {
  if (deviceTilt.y > 0.5f)
   billIndex = 5;
  else
   billIndex = 1;
 }
 else if(billIndex > 1) {
  if (deviceTilt.x > 0.5f)
   billIndex = 3;
  else if (deviceTilt.x < -0.5f)
   billIndex = 4;
  else
   billIndex = 2;
   
 }
 
 
 switch (billIndex) {
  case 2:
   dollarImage = [UIImage imageNamed:@"dol2.png"];
   break;
  case 3:
   dollarImage = [UIImage imageNamed:@"5dol.jpg"];
   break;
  case 4:
   dollarImage = [UIImage imageNamed:@"10dol.jpg"];
   break;
  case 5:
   dollarImage = [UIImage imageNamed:@"20dol.jpg"];
   break;   
  default:
   dollarImage = [UIImage imageNamed:@"dollar.png"];
   break;
 }
 //以上是檢測觸點，並分配不同的美元圖片
 // for effect only draw one 2 dollar bill by resetting billIndex
 if (billIndex == 2)
  billIndex = 1;
 //以下是動畫部分的核心代碼
 dollarView = [[UIImageView alloc] initWithImage:dollarImage];
 int scale = RANDOM_INT(1, 5);
 int width = 100*scale;
 int height = 44*scale;
 if(useEmitterRect) {
  dollarView.frame = emitterRect;
 //} else if (deviceTilt.x > 0.5f || deviceTilt.y > 0.5f || deviceTilt.x < -0.5f || deviceTilt.y < -0.5f) {
 } else if (deviceTilt.y > 0.5f) {
  dollarView.frame = CGRectMake(160 - (width/2), 490, width, height);
 } else if (deviceTilt.y < -0.5f) {
  dollarView.frame = CGRectMake(160 - (width/2), -(height+10), width, height);
 } else if (deviceTilt.x > 0.5f) {
  dollarView.frame = CGRectMake(-(width+10), 240-(height/2), width, height);
 } else if (deviceTilt.x < -0.5f) {
  dollarView.frame = CGRectMake(330, 240-(height/2), width, height);
 } else {
  switch (RANDOM_INT(0, 3)) {
   case 0:
    dollarView.frame = CGRectMake(-300, -300, 100*scale, 44*scale);
    break;
   case 1:
    dollarView.frame = CGRectMake(470, -150, 100*scale, 44*scale);
    break;
   case 3:
    dollarView.frame = CGRectMake(470, 630, 100*scale, 44*scale);
    break;   
   default:
    dollarView.frame = CGRectMake(-150, 630, 100*scale, 44*scale);
    break;
  }
 }
 
 [self addSubview:dollarView];
 if(helpView)
  [self bringSubviewToFront:helpView];
 
 [UIView beginAnimations:nil context:dollarView];
 [UIView setAnimationDuration:2];

 dollarView.frame = CGRectMake(RANDOM_INT(-50, 370), RANDOM_INT(-25, 665), 100, 44);
  
 int radians = RANDOM_INT(0, 360) * 0.0174532925;  
 [dollarView setTransform:CGAffineTransformMakeRotation(radians)];
 
 [UIView setAnimationDelegate:self];
 [UIView commitAnimations];
 
 billCount++;
 [billList addObject:dollarView];
 if([billList count] >= MAX_BILLS) {
  UIImageView* oldBill = (UIImageView*)[billList objectAtIndex:0];
  [billList removeObjectAtIndex:0];
  
  [UIView beginAnimations:nil context:oldBill];
  
  [UIView setAnimationDuration:2];
  [oldBill setAlpha:0.0];
  
  [UIView setAnimationDelegate:self];
  [UIView setAnimationDidStopSelector:@selector(goPutThemBack:finished:context:)];
  [UIView commitAnimations];
 }
 
}