10.2在xib文件中已经创建好Button，通过tag获取按钮
UIButton *testButton= (UIButton*)[self.view viewWithTag:100];
[testButton addTarget:self action:@selector(test:) forControlEvents:UIControlEventTouchUpInside];
//按钮事件
-(void) test: (id) sender{
UIAlertView *av = [[[UIAlertView alloc] initWithTitle:@"ceshi" message:@"test11111" delegate:nil cancelButtonTitle:@"OK"otherButtonTitles:nil] autorelease];
[av show];
}
11.让某个控件在View的中心位置显示：
// 设置文字的字体
cell.textLabel.font = [UIFont fontWithName:@"AmericanTypewriter" size:100.0f];
// 设置文字的颜色
cell.textLabel.textColor = [UIColor orangeColor];
// 设置文字的背景颜色
cell.textLabel.shadowColor = [UIColor whiteColor];
// 设置文字的显示位置
cell.textLabel.textAlignment = UITextAlignmentCenter;
在程序的 viewDidLoad 中加入
UIAlertView *theAlert = [[[UIAlertViewalloc] initWithTitle:@"Atention"
message: @"I'm a Chinese!"
delegate:nil
cancelButtonTitle:@"Cancel"
otherButtonTitles:@"Okay",nil] autorelease];
[theAlert show];
UIImage *theImage = [UIImageimageNamed:@"loveChina.png"];
theImage = [theImage stretchableImageWithLeftCapWidth:0topCapHeight:0];
CGSize theSize = [theAlert frame].size;
UIGraphicsBeginImageContext(theSize);
[theImage drawInRect:CGRectMake(5, 5, theSize.width-10, theSize.height-20)];// 这个地方的大小要自己调整，以适应 alertview 的背景颜色的大小。
theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
theAlert.layer.contents = (id)[theImage CGImage];
textField.keyboardAppearance = UIKeyboardAppearanceAlert;
16.状态栏的网络活动风火轮是否旋转：
[UIApplication sharedApplication].networkActivityIndicatorVisible ， 默认值是 NO 。
// 创建一个基于位 图的图形上下文并指定大小为CGSizeMake(200,400)
UIGraphicsBeginImageContext(CGSizeMake(200,400));
//renderInContext 呈现接受者及其子范围到 指定的上下文
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
// 返回 一个基于当前图形上下文的图片
UIImage *aImage = UIGraphicsGetImageFromCurrentImageContext();
// 移除栈顶 的基于当前位图的图形上下文
UIGraphicsEndImageContext();
// 以 png 格式 返回指定图片的数据
imageData = UIImagePNGR epresentation(aImage);
UIView *myview = [[UIView alloc] init];
myview.frame = CGRectMake(0, 0, 320, 47);
myview.backgroundColor = [UIColorcolorWithPatternImage:[UIImage imageNamed:@"0006.png"]];
cell.selectedBackgroundView = myview;:
19.显示图片：
CGRect myImageRect = CGRectMake(0.0f, 0.0f, 320.0f, 109.0f);
UIImageView *myImage = [[UIImageView alloc] initWithFrame:myImageRect];
[myImage setImage:[UIImage imageNamed:@"myImage.png"]];
myImage.opaque = YES; //opaque 是否透明
[self.view addSubview:myImage];
UIImage *image = [[UIImage alloc]initWithContentsOfFile:imagePath];
UIImage *newImage= [image transformWidth:80.f height:240.f];
UIImageView *imageView = [[UIImageView alloc]initWithImage: newImage];
[newImagerelease];
[image release];
[self.view addSubview:imageView];
22.键盘回收：
1).增加一个button，相应touch down事件，隐藏键盘。这种方法，太山寨了。为了相应一个事件增加一个button太不值得的。
.h
- (IBAction)dismissKeyBoard:(id)sender;
.m
- (IBAction)dismissKeyBoard:(id)sender {
[testText resignFirstResponder];
}
2).第二种方法：在背景图片上添加Tap事件，相应单击处理。这种方法，很好代替了button方式，但是如果UI上没有背景图片，这种方法又回到到第一种山寨的方法行列中。
// 添加带有处理时间的背景图片
UIImageView *backView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
backView.image = [UIImage imageNamed:@"small3.png"];
backView.userInteractionEnabled = YES;
UITapGestureRecognizer *singleTouch = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(dismissKeyboard:)];
[backView addGestureRecognizer:singleTouch];
backView.tag = 110;
[self.view addSubview:backView];
-(void)dismissKeyboard:(id)sender{
[text resignFirstResponder];
}
3).在xib文件中，修改xib文件的objects属性，默认是view属性，我们可以修改为UIControl属性，从而是xib文件相应touch down事件。这种方法，缺点就是没有xib就悲剧了。
.h
- (IBAction)dimissKeyboard:(id)sender;
.m
- (IBAction)dimissKeyboard:(id)sender {
[text resignFirstResponder];
}
23、Gif图片的解析
//加载gif
NSString *filePath = [[NSBundle mainBundle]pathForResource:@"bai3" ofType:@"gif"];
NSData *data = [NSData dataWithContentsOfFile:filePath];
CGImageSourceRef gif = CGImageSourceCreateWithData((CFDataRef)data, nil);
//获取gif的各种属性
CFDictionaryRef gifprops =(CGImageSourceCopyPropertiesAtIndex(gif,0,NULL));
NSLog(@"_______%@",gifprops);
NSInteger count =CGImageSourceGetCount(gif);
NSLog(@"________%d",count);
CFDictionaryRef gifDic = CFDictionaryGetValue(gifprops, kCGImagePropertyGIFDictionary);
CFDictionaryRef delay = CFDictionaryGetValue(gifDic, kCGImagePropertyGIFDelayTime);
NSLog(@"_______%@",delay);
//[gifDic objectForKey:(NSString *)kCGImagePropertyGIFDelayTime];
// NSNumber * w = CFDictionaryGetValue(gifprops, @"PixelWidth");
// NSNumber * h =CFDictionaryGetValue(gifprops, @"PixelHeight");
// float totalDuration = delay.doubleValue * count;
// float pixelWidth = w.intValue;
// float pixelHeight = h.intValue;
//将gif解析成UIImage类型对象，并加进images数组中
NSMutableArray *images = [NSMutableArray arrayWithCapacity:count];
for(int index=0;index<count;index++)
{
CGImageRef ref = CGImageSourceCreateImageAtIndex(gif, index, nil);
UIImage *img = [UIImage imageWithCGImage:ref];
[images addObject:img];
CFRelease(ref);
}
CFRelease(gifprops);
CFRelease(gif);
Gif的合成
- (void)exportAnimatedGif:(CGImageSourceRef )gif :(NSMutableArray *)images
{
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"animated.gif"];
CGImageDestinationRef destination = CGImageDestinationCreateWithURL(( CFURLRef)[NSURL fileURLWithPath:path],
kUTTypeGIF,
images.count,
NULL);
UIImage *image;
for (int i = 0; i<images.count; i++)
{
image = images[i];
CFDictionaryRef gifprops =(CGImageSourceCopyPropertiesAtIndex(gif,i,NULL));
CFDictionaryRef gifDic = CFDictionaryGetValue(gifprops, kCGImagePropertyGIFDictionary);
NSNumber *delay = CFDictionaryGetValue(gifDic, kCGImagePropertyGIFDelayTime);
NSDictionary *gifDelay = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:delay forKey:(NSString *)kCGImagePropertyGIFDelayTime]
forKey:(NSString *)kCGImagePropertyGIFDictionary];
CGImageDestinationAddImage(destination,image.CGImage, (CFDictionaryRef)gifDelay);
CGImageDestinationSetProperties(destination, ( CFDictionaryRef)gifprops);
}
// CGImageDestinationSetProperties(destination, ( CFDictionaryRef)gifprops);
CGImageDestinationFinalize(destination);
CFRelease(destination);
NSLog(@"animated GIF file created at %@", path);
}
24.将一个UIView对象的内容保存为UIImage
+ (UIImage*)imageFromView:(UIView*)view{
UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, view.layer.contentsScale);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
注意：生成的图片的scale和view的scale一致，这样才可以保证图片的效果和view显示的完全一致，使用renderInContext方法可以让subviews的内容也显示的图片里。
25.捕捉屏幕截图
CALayer实例使用Core Graphics的renderInContext方法可以将视图绘制到图像上下文中以便转化为其他UIImage实例。前提先#import <QuartzCore/QuartzCore.h>
+ (UIImage *) imageFromView: (UIView *)theView {
// draw a view's contents into an image context
UIGraphicsBeginImageContext(theView.frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[theView.layer renderInContext:context];
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return theImage;
}
注：UIGraphicsBeginImageContext(CGSize size)创建一个基于位图的上下文(context)，并将其设置为当前上下文。函数功能与UIGraphicsBeginImageContextWithOptions相同，相当于该方法的opaque参数为NO，scale因子为1.0。而UIGraphicsEndImageContext()方法是移除栈顶的基于当前位图的图形上下文。
26.捕捉截取某个区域内屏幕图像
- (UIImage *)imageFromView: (UIView *) theView atFrame:(CGRect)rect
{
UIGraphicsBeginImageContext(theView.frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
UIRectClip(rect);
[theView.layer renderInContext:context];
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return theImage;//[self getImageAreaFromImage:theImage atFrame:rect];
}
27.从某图片中截图
UIImage *image = [[UIImage alloc] initWithData:data];//大图
CGRect imageRect = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
CGSize itemSize = CGSizeMake(w,h);
UIGraphicsBeginImageContext(itemSize);
[image drawInRect:imageRect];
UIImage *smallimage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
28.视图添加倒影效果
const CGFloat kReflectPercent = -0.25f;
const CGFloat kReflectOpacity = 0.3f;
const CGFloat kReflectDistance = 10.0f;
+ (void)addSimpleReflectionToView:(UIView *)theView
{
CALayer *reflectionLayer = [CALayer layer];
reflectionLayer.contents = [theView layer].contents;
reflectionLayer.opacity = kReflectOpacity;
reflectionLayer.frame = CGRectMake(0.0f,0.0f,theView.frame.size.width,theView.frame.size.height*kReflectPercent); //倒影层框架设置，其中高度是原视图的百分比
CATransform3D stransform = CATransform3DMakeScale(1.0f,-1.0f,1.0f);
CATransform3D transform = CATransform3DTranslate(stransform,0.0f,-(kReflectDistance + theView.frame.size.height),0.0f);
reflectionLayer.transform = transform;
reflectionLayer.sublayerTransform = reflectionLayer.transform;
[[theView layer] addSublayer:reflectionLayer];
}
另一：使用Core Graphics创建倒影
+ (CGImageRef) createGradientImage:(CGSize)size
{
CGFloat colors[] = {0.0,1.0,1.0,1.0};
//在灰色设备色彩上建立一渐变
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
CGContextRef context = CGBitmapContextCreate(nil,size.width,size.height,8,0,colorSpace,kCGImageAlphaNone);
CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace,colors,NULL,2);
CGColorSpaceRelease(colorSpace);
//绘制线性渐变
CGPoint p1 = CGPointZero;
CGPoint p2 = CGPointMake(0,size.height);
CGContextDrawLinearGradient(context,gradient,p1,p2,kCGGradientDrawsAfterEndLocation);
//Return the CGImage
CGImageRef theCGImage = CGBitmapContextCreateImage(context);
CFRelease(gradient);
CGContextRelease(context);
return theCGImage;
}
//Create a shrunken frame for the reflection
+ (UIImage *) reflectionOfView:(UIView *)theView WithPercent:(CGFloat) percent
{
//Retain the width but shrink the height
CGSize size = CGSizeMake(theView.frame.size.width, theView.frame.size.height * percent);
//Shrink the View
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
[theView.layer renderInContext:context];
UIImage *partialimg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//build the mask
CGImageRef mask = [ImageHelper createGradientImage:size];
CGImageRef ref = CGImageCreateWithMask(partialimg.CGImage,mask);
UIImage *theImage = [UIImage imageWithCGImage:ref];
CGImageRelease(ref);
CGImageRelease(mask);
return theImage;
}
const CGFloat kReflectDistance = 10.0f;
+ (void) addReflectionToView: (UIView *)theView
{
theView.clipsToBounds = NO;
UIImageView *reflection = [[UIImageView alloc] initWithImage:[ImageHelper reflectionOfView:theView withPercent:0.45f]];
CGRect frame = reflection.frame;
frame.origin = CGPointMake(0.0f, theView.frame.size.height + kReflectDistance);
reflection.frame = frame;
// add the reflection as a simple subview
[theView addSubView:reflection];
[reflection release];
}
29.实现圆角图片：
UIColor *color = [UIColor colorWithRed:0.95 green:0.95 blue:0.95 alpha:0];
[aImage setBackgroundColor:color]; //设置背景透明
/******设置图片圆角begin*******/
aImage.layer.masksToBounds = YES;
aImage.layer.cornerRadius = 5.0;
aImage.layer.borderWidth = 0.5;
aImage.layer.borderColor = [[UIColor grayColor] CGColor];
/******设置图片圆角end********/
另有方法可见：http://www.4ucode.com/Study/Topic/2058289转载文章。
30.实现iPhone图标的水晶立体效果
- (void)viewDidLoad {
[super viewDidLoad];
UIGraphicsBeginImageContext(icon.bounds.size);
CGContextRef ctx = UIGraphicsGetCurrentContext();
const CGFloat components[4] = {0.0,0.4,0.0,1.0};
CGContextSetFillColor(ctx, components);
CGContextFillRect(ctx, CGRectMake(0, 0, icon.bounds.size.width, icon.bounds.size.height));
UIImage *background = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImage *image = [UIImage imageNamed:@"icon.png"];
UIImage *mask = [UIImage imageNamed:@"IconBase.png"];
UIImage *roundCorner = [UIImage imageNamed:@"round-corner.png"];
icon.image = image;
CALayer* subLayer = [[CALayer layer] retain];
subLayer.frame = icon.bounds;
subLayer.contents = (id)[background CGImage];
CALayer* maskLayer = [[CALayer layer] retain];
maskLayer.frame = icon.bounds;
maskLayer.contents = (id)[mask CGImage];
[subLayer setMask:maskLayer];
[[icon layer] addSublayer:subLayer];
CALayer* roundCornerLayer = [[CALayer layer] retain];
roundCornerLayer.frame = icon.bounds;
roundCornerLayer.contents = (id)[roundCorner CGImage];
[[icon layer] setMask:roundCornerLayer];
[maskLayer release];
[subLayer release];
[roundCornerLayer release];
}
31.两图合成一图
- (UIImage*)addImage:(UIImage *)image1 toImage:(UIImage*)image2
{
UIGraphicsBeginImageContext(image1.size);
[image1 drawInRect:CGRectMake(0,0,image1.size.width,image1.size.height)];
[image2 drawInRect:CGRectMake(0,0,image2.size.width,image2.size.height)];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resultingImage;
}
参考链接
1.http://www.cnblogs.com/lovecode/archive/2011/11/12/2246421.html
2.http://my.oschina.net/u/819843/blog/98574