iOS調用系統攝像頭和相冊
在一些應用中，我們需要用到iOS設備的攝像頭進行拍照，視頻。并且從相冊中選取我們需要的圖片或者視頻。
關于iOS攝像頭和相冊的應用，可以使用UIImagePickerController類來完成控制。
關于UIImagePickerController的相關知識，
如下：
iOS的一些設備上都安裝了攝像頭。現在絕大多數都有了。
在編程中，我們是用相應的東西來進行照相，錄像等功能。
一、UIImagePickerController類
UIImagePickerController 這個類可以為大家提供照相的功能,以及圖片,視頻瀏覽的功能。
二、檢查硬件是否安裝有攝像頭或者允許操作相冊
這些公共的方法，我們也許會用到，我就貼了！So easy！！！
#pragma mark - 攝像頭和相冊相關的公共類
// 判斷設備是否有攝像頭
- (BOOL) isCameraAvailable{
return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];
}
// 前面的攝像頭是否可用
- (BOOL) isFrontCameraAvailable{
return [UIImagePickerControllerisCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront];
}
// 后面的攝像頭是否可用
- (BOOL) isRearCameraAvailable{
return [UIImagePickerControllerisCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];
}
// 判斷是否支持某種多媒體類型：拍照，視頻
- (BOOL) cameraSupportsMedia:(NSString *)paramMediaType sourceType:(UIImagePickerControllerSourceType)paramSourceType{
__block BOOL result = NO;
if ([paramMediaType length] == ){
NSLog(@"Media type is empty.");
return NO;
}
NSArray *availableMediaTypes =[UIImagePickerControlleravailableMediaTypesForSourceType:paramSourceType];
[availableMediaTypes enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL*stop) {
NSString *mediaType = (NSString *)obj;
if ([mediaTypeisEqualToString:paramMediaType]){
result = YES;
*stop= YES;
}
}];
return result;
}
// 檢查攝像頭是否支持錄像
- (BOOL) doesCameraSupportShootingVideos{
return [self cameraSupportsMedia:( NSString *)kUTTypeMoviesourceType:UIImagePickerControllerSourceTypeCamera];
}
// 檢查攝像頭是否支持拍照
- (BOOL) doesCameraSupportTakingPhotos{
return [self cameraSupportsMedia:( NSString *)kUTTypeImagesourceType:UIImagePickerControllerSourceTypeCamera];
}
#pragma mark - 相冊文件選取相關
//相冊是否可用
- (BOOL) isPhotoLibraryAvailable{
return [UIImagePickerControllerisSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary];
}
//是否可以在相冊中選擇視頻
- (BOOL) canUserPickVideosFromPhotoLibrary{
return [selfcameraSupportsMedia:( NSString *)kUTTypeMovie sourceType:UIImagePickerControllerSourceTypePhotoLibrary];
}
//是否可以在相冊中選擇視頻
- (BOOL) canUserPickPhotosFromPhotoLibrary{
return [selfcameraSupportsMedia:( NSString *)kUTTypeImage sourceType:UIImagePickerControllerSourceTypePhotoLibrary];
}
三、用攝像頭進行拍照和錄像功能
1.我們將UIImagePickerController功能寫在一個按鈕的點擊事件中：
#pragma mark -拍照按鈕事件
- (void)ClickControlAction:(id)sender{
//判斷有攝像頭，并且支持拍照功能
if ([selfisCameraAvailable] && [selfdoesCameraSupportTakingPhotos]){
// 初始化圖片選擇控制器
UIImagePickerController *controller = [[UIImagePickerController alloc]init];
[controllersetSourceType:UIImagePickerControllerSourceTypeCamera];//設置類型
//設置所支持的類型，設置只能拍照，或則只能錄像，或者兩者都可以
NSString *requiredMediaType = (NSString *)kUTTypeImage;
NSString *requiredMediaType1 = (NSString *)kUTTypeMovie;
NSArray *arrMediaTypes=[NSArray arrayWithObjects:requiredMediaType, requiredMediaType1,nil];
[controller setMediaTypes:arrMediaTypes];
// 設置錄制視頻的質量
[controllersetVideoQuality:UIImagePickerControllerQualityTypeHigh];
//設置最長攝像時間
[controller setVideoMaximumDuration:10.f];
[controller setAllowsEditing:YES];//設置是否可以管理已經存在的圖片或者視頻
[controller setDelegate:self];// 設置代理
[self.navigationControllerpresentModalViewController:controller animated:YES];
[controller release];
}else {
NSLog(@"Camera is not available.");
}
}
解釋：
2. setSourceType方法
通過設置setSourceType方法可以確定調用出來的UIImagePickerController所顯示出來的界面
typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {
UIImagePickerControllerSourceTypePhotoLibrary,
UIImagePickerControllerSourceTypeCamera,
UIImagePickerControllerSourceTypeSavedPhotosAlbum
};
分別表示：圖片列表，攝像頭，相機相冊
3.setMediaTypes方法
// 設置所支持的類型，設置只能拍照，或則只能錄像，或者兩者都可以
NSString *requiredMediaType = ( NSString *)kUTTypeImage;
NSString *requiredMediaType1 = ( NSString *)kUTTypeMovie;
NSArray *arrMediaTypes=[NSArray arrayWithObjects:requiredMediaType, requiredMediaType1,nil];
[controller setMediaTypes:arrMediaTypes];
4.關于UIImagePickerControllerDelegate協議
我們要對我們拍攝的照片和視頻進行存儲，那么就要實現UIImagePickerControllerDelegate協議的方法。
#pragma mark - UIImagePickerControllerDelegate 代理方法
//保存圖片后到相冊后，調用的相關方法，查看是否保存成功
- (void) imageWasSavedSuccessfully:(UIImage *)paramImage didFinishSavingWithError:(NSError *)paramError contextInfo:(void*)paramContextInfo{
if (paramError == nil){
NSLog(@"Image was saved successfully.");
} else {
NSLog(@"An error happened while saving the image.");
NSLog(@"Error = %@", paramError);
}
}
//當得到照片或者視頻后，調用該方法
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
NSLog(@"Picker returned successfully.");
NSLog(@"%@", info);
NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
// 判斷獲取類型：圖片
if ([mediaType isEqualToString:( NSString *)kUTTypeImage]){
UIImage*theImage = nil;
// 判斷，圖片是否允許修改
if ([pickerallowsEditing]){
//獲取用戶編輯之后的圖像
theImage = [info objectForKey:UIImagePickerControllerEditedImage];
} else {
// 照片的元數據參數
theImage = [info objectForKey:UIImagePickerControllerOriginalImage];
}
// 保存圖片到相冊中
SELselectorToCall = @selector(imageWasSavedSuccessfully:didFinishSavingWithError:contextInfo:);
UIImageWriteToSavedPhotosAlbum(theImage,self,selectorToCall,NULL);
}else if([mediaType isEqualToString:(NSString *)kUTTypeMovie]){
// 判斷獲取類型：視頻
//獲取視頻文件的url
NSURL* mediaURL = [info objectForKey:UIImagePickerControllerMediaURL];
//創建ALAssetsLibrary對象并將視頻保存到媒體庫
// Assets Library 框架包是提供了在應用程序中操作圖片和視頻的相關功能。相當于一個橋梁，鏈接了應用程序和多媒體文件。
ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
// 將視頻保存到相冊中
[assetsLibrarywriteVideoAtPathToSavedPhotosAlbum:mediaURL
completionBlock:^(NSURL *assetURL, NSError *error) {
if (!error) {
NSLog(@"captured video saved with no error.");
}else{
NSLog(@"error occured while saving the video:%@", error);
}
}];
[assetsLibrary release];
}
[picker dismissModalViewControllerAnimated:YES];
}
//當用戶取消時，調用該方法
- (void)imagePickerControllerDidCancel:(UIImagePickerController*)picker{
[picker dismissModalViewControllerAnimated:YES];
}
四、從相冊獲取圖片和視頻數據
1.我們將功能封裝在一個按鈕的點擊事件中
#pragma mark - 相冊操作
- (void)ClickShowPhotoAction:(id)sender{
if([self isPhotoLibraryAvailable]){
UIImagePickerController *controller = [[UIImagePickerController alloc]init];
[controller setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];//設置類型
NSMutableArray *mediaTypes = [[NSMutableArray alloc] init];
if ([selfcanUserPickPhotosFromPhotoLibrary]){
[mediaTypes addObject:(NSString *)kUTTypeImage];
}
if ([selfcanUserPickVideosFromPhotoLibrary]){
[mediaTypes addObject:(NSString *)kUTTypeMovie];
}
[controller setMediaTypes:mediaTypes];
[controller setDelegate:self];// 設置代理
[self.navigationControllerpresentModalViewController:controller animated:YES];
[controller release];
[mediaTypes release];
}
}
2.關于UIImagePickerControllerDelegate協議，我們可以重用。
在這里，就不用贅述了！
最后，需要說的是，UIImagePickerControllerDelegate協議中
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary*)info方法，中的info值，會根據我們操作的類型不同，而產生了不同的數據信息：
當操作的為圖片時：：
{
UIImagePickerControllerCropRect = "NSRect: {{0, 405}, {2448, 2449}}";
UIImagePickerControllerEditedImage = "";
UIImagePickerControllerMediaMetadata = {
DPIHeight = 72;
DPIWidth = 72;
Orientation = 6;
"{Exif}" = {
ApertureValue = "2.526068811667588";
BrightnessValue = "-0.0709875088566263";
ColorSpace = 1;
DateTimeDigitized = "2013:04:05 16:43:00";
DateTimeOriginal = "2013:04:05 16:43:00";
ExposureMode = 0;
ExposureProgram = 2;
ExposureTime = "0.05882352941176471";
FNumber = "2.4";
Flash = 24;
FocalLenIn35mmFilm = 35;
FocalLength = "4.28";
ISOSpeedRatings = (
400
);
MeteringMode = 5;
PixelXDimension = 3264;
PixelYDimension = 2448;
SceneType = 1;
SensingMethod = 2;
Sharpness = 0;
ShutterSpeedValue = "4.099543917546131";
SubjectArea = (
1631,
1223,
881,
881
);
WhiteBalance = 0;
};
"{TIFF}" = {
DateTime = "2013:04:05 16:43:00";
Make = Apple;
Model = "iPhone 4S";
Software = "5.1.1";
XResolution = 72;
YResolution = 72;
};
};
UIImagePickerControllerMediaType = "public.image";
UIImagePickerControllerOriginalImage = "";
}
當我們操作的為視頻時：
{
UIImagePickerControllerMediaType = "public.movie";
UIImagePickerControllerMediaURL = "file://localhost/private/var/mobile/Applications/22A14825-DD7E-48E1-A1D5-2D85B82095B5/tmp/capture-T0x1363a0.tmp.etXfD4/capturedvideo.MOV";
}
希望對你有所幫助！