UIImagePickerController学习

UIImagePickerController概述：

UIImagePickerController 类是获取选择图片和视频的用户接口。我们可以用这个controller选择我们所需要的图片和视频。对于这个类来说比较特殊，我们不能够任意定制，也不可以继承生成子类。

我们在用UIImagePickerController类的时候，只需要调用用代码实现其在什么位置显示和开始，当然我们之后可以选择所需的图片和影片，或者也可以不选择点击取消即可。

但是在我们调用接口之前，我们需要确认：

一：当前设备是否支持使用UIImagePickerController，这个时候我们需要调用isSourceTypeAvailable:方法判断。

二：查看符合的媒体类型（图片或者视频），这个时候我们调用availableMediaTypesForSourceType: 方法判断。

同时使用UIImagePickerController时，我们需要UIImagePickerControllerDelegate协议代理实现一些特定时间特定的动作。在调用摄像头的时候我们可以选择使用闪光灯，但是默认条件下对视频有10分钟的限制，需要用videoMaximumDuration属性更改默认时间，

三：之后我们设定界面媒体的属性

1：sourceType //从哪选取媒体

enum {

UIImagePickerControllerSourceTypePhotoLibrary,

UIImagePickerControllerSourceTypeCamera,

UIImagePickerControllerSourceTypeSavedPhotosAlbum

};

typedef NSUInteger UIImagePickerControllerSourceType;

2: mediaTypes

mediaTypes用来确定再picker里显示那些类型的多媒体文件，图片？视频？

+ (NSArray *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType

一共有三个可选的代理方法UIImagePickerControllerDelegate

– imagePickerController:didFinishPickingMediaWithInfo:

– imagePickerControllerDidCancel:

– imagePickerController:didFinishPickingImage:editingInfo:

-(void)pick{

[imagePickertakePicture];

}

-(IBAction)press:(id)sender {

imagePicker= ［UIImagePickerController alloc] init];

imagePicker.delegate= self;

imagePicker.mediaTypes= [UIImagePickerControlleravailableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];

imagePicker.sourceType= UIImagePickerControllerSourceTypeCamera;

imagePicker.showsCameraControls= NO;

UIView*view = ［UIView alloc] initWithFrame:CGRectMake(0, 0, 320,44)];

view.backgroundColor= [UIColor redColor];

UIButton*button = ［UIButton alloc] initWithFrame:CGRectMake(0, 0, 40,40)];

button.backgroundColor= [UIColor blueColor];

[buttonaddTarget:self action:@selector(pick)forControlEvents:UIControlEventTouchUpInside];

[viewaddSubview:button];

CGRectnewFrame = CGRectMake(0.0,436,320,44);

view.frame= newFrame;

imagePicker.cameraOverlayView= view;

[selfpresentModalViewController:imagePickeranimated:YES];

}

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

if(［info objectForKey:UIImagePickerControllerMediaType]isEqualToString:(NSString*)kUTTypeImage]) {

UIImage*image = [infoobjectForKey:UIImagePickerControllerOriginalImage];

UIImageWriteToSavedPhotosAlbum(image,self, @selector(image:didFinishSavingWithError:contextInfo:),nil);

} elseif (［info objectForKey:UIImagePickerControllerMediaType]isEqualToString:(NSString*)kUTTypeMovie]) {

NSString*path = ［info objectForKey:UIImagePickerControllerMediaURL]path];

UISaveVideoAtPathToSavedPhotosAlbum(path,self, @selector(video:didFinishSavingWithError:contextInfo:),nil);

}

[pickerdismissModalViewControllerAnimated:YES];

}

-(void)imagePickerControllerDidCancel:(UIImagePickerController*)picker {

[pickerdismissModalViewControllerAnimated:YES];

}

UIImagePickerController －－ the only sanctioned way to get videos/movies or images/pictures on supported devices 用UIImagePickerController选择、显示图片或视频，主要注意UIImagePickerController几个属性的设置 一：UI 显示样式，显示的格式确定 1：sourceType @property(nonatomic) UIImagePickerControllerSourceType sourceType enum { UIImagePickerControllerSourceTypePhotoLibrary, UIImagePickerControllerSourceTypeCamera, UIImagePickerControllerSourceTypeSavedPhotosAlbum }; typedef NSUInteger UIImagePickerControllerSourceType; sourceType用来确定用户界面显示的样式： 共三种格式（模拟器上的效果图） UIImagePickerControllerSourceTypePhotoLibrary, UIImagePickerControllerSourceTypeCamera, UIImagePickerControllerSourceTypeSavedPhotosAlbum 为了区分是否支持视频格式，一般要用到下面这个函数，以便确定mediaTypes。 + (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType 2: mediaTypes @property(nonatomic,copy) NSArray *mediaTypes mediaTypes用来确定再picker里显示那些类型的多媒体文件，图片？视频？ + (NSArray *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType 二：选取动作处理 UIImagePickerControllerDelegate 通过代理来完成用户在选中图片，或者choose视频时的处理方式： 共有三个可选的代理方法 – imagePickerController:didFinishPickingMediaWithInfo: – imagePickerControllerDidCancel: – imagePickerController:didFinishPickingImage:editingInfo: Deprecated in iPhone OS 3.0 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info info中包括选取的照片，视频的主要信息 NSString *const UIImagePickerControllerMediaType; 选取的类型 public.image public.movie NSString *const UIImagePickerControllerOriginalImage; 修改前的UIImage object. NSString *const UIImagePickerControllerEditedImage; 修改后的UIImage object. NSString *const UIImagePickerControllerCropRect; 原始图片的尺寸NSValue object containing a CGRect data type NSString *const UIImagePickerControllerMediaURL; 视频在文件系统中 的 NSURL地址 保存视频主要时通过获取其NSURL 然后转换成NSData 实例代码如下： - (void) pickImage: (id) sender { UIImagePickerController *ipc = [[UIImagePickerController alloc] init]; if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]){ ipc.sourceType = UIImagePickerControllerSourceTypePhotoLibrary; ipc.mediaTypes =[UIImagePickerController availableMediaTypesForSourceType:ipc.sourceType]; } ipc.delegate = self; ipc.allowsImageEditing = NO; [self presentModalViewController:ipc animated:YES]; } - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType]; if ([mediaType isEqualToString:@"public.image"]){ // UIImage *selectedImage = [info objectForKey:UIImagePickerControllerOriginalImage]; UIImage *image = [info objectForKey:@"UIImagePickerControllerOriginalImage"]; NSLog(@"found an image"); [UIImageJPEGRepresentation(image, 1.0f) writeToFile:[self findUniqueSavePath] atomically:YES]; SETIMAGE(image); CFShow([[NSFileManager defaultManager] directoryContentsAtPath:[NSHomeDirectory() stringByAppendingString:@"/Documents"]]); } else if ([mediaType isEqualToString:@"public.movie"]){ NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL]; NSLog(@"found a video"); NSData *webData = [NSData dataWithContentsOfURL:videoURL]; //NSData *video = [[NSString alloc] initWithContentsOfURL:videoURL]; [webData writeToFile:[self findUniqueMoviePath] atomically:YES]; CFShow([[NSFileManager defaultManager] directoryContentsAtPath:[NSHomeDirectory() stringByAppendingString:@"/Documents"]]); // NSLog(videoURL); } [picker dismissModalViewControllerAnimated:YES]; }