python 使用sqlite3

原文地址 http://blog.csdn.net/u010424349/article/details/9139183 马上就要开项目了，大哥让我写个控件出来，到时候可以直接用。好了闲话不多说，直接说思路。
1、UIScrollView下图片的捏合放大和缩小，我们直接用scrollView自带的属性就可以了，这个没什么好说，我们直接贴代码：[plain] view plaincopy
//控制器

theScroll=[[UIScrollView alloc] initWithFrame:frame];

theScroll.userInteractionEnabled=YES;

theScroll.maximumZoomScale=2.0;//最大倍率（默认倍率）

theScroll.minimumZoomScale=1.0;//最小倍率（默认倍率）

theScroll.decelerationRate=1.0;//减速倍率（默认倍率）

theScroll.delegate=self;

theScroll.autoresizingMask =UIViewAutoresizingFlexibleLeftMargin|UIViewAutoresizingFlexibleTopMargin|UIViewAutoresizingFlexibleHeight;

[self addSubview:theScroll];

//图片

UIImage *theImageName=[UIImage imageNamed:imageName];

theImage=[[UIImageView alloc] initWithImage:theImageName];

theImage.userInteractionEnabled=YES;

theImage.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin|UIViewAutoresizingFlexibleTopMargin|UIViewAutoresizingFlexibleHeight;

//图片默认作为2倍图处理

theImage.frame=CGRectMake(0, 0, theImageName.size.width/2, theImageName.size.height/2);

[theScroll addSubview:theImage];

另外，我们还要在scrollView的delegate里面设置一下：[plain] view plaincopy
#pragma mark -UIScrollView delegate

-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView

{

return theImage;

}

2、scrollView对图片的双击放大和缩小这里我是通过对双击手势（UIGestureRecognizer）和scrollView的setZoomScale方法来实现放大和缩小。#创建双击手势[plain] view plaincopy
//双击手势

UITapGestureRecognizer *doubelGesture=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleGesture:)];

doubelGesture.numberOfTapsRequired=2;

[theImage addGestureRecognizer:doubelGesture];

[doubelGesture release];

#另外，我们要记录当前的倍率，然后通过判断，是放大还是缩小。当然，还配合捏合的放大和缩小，所以，要在scrollView的delegate里面记录当前倍率，代码：[plain] view plaincopy
-(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale

{

currentScale=scale;

}

#双击手势的方法

[plain] view plaincopy
#pragma mark -DoubleGesture Action

-(void)doubleGesture:(UIGestureRecognizer *)sender

{

//当前倍数等于最大放大倍数

//双击默认为缩小到原图

if (currentScale==_maxScale) {

currentScale=minScale;

[theScroll setZoomScale:currentScale animated:YES];

return;

}

//当前等于最小放大倍数

//双击默认为放大到最大倍数

if (currentScale==minScale) {

currentScale=_maxScale;

[theScroll setZoomScale:currentScale animated:YES];

return;

}

CGFloat aveScale =minScale+(_maxScale-minScale)/2.0;//中间倍数

//当前倍数大于平均倍数

//双击默认为放大最大倍数

if (currentScale>=aveScale) {

currentScale=_maxScale;

[theScroll setZoomScale:currentScale animated:YES];

return;

}

//当前倍数小于平均倍数

//双击默认为放大到最小倍数

if (currentScale<aveScale) {

currentScale=minScale;

[theScroll setZoomScale:currentScale animated:YES];

return;

}

}