相机，闪光灯

IOS开发调用系统相机和打开闪光灯

今天给大家分享一下如何调用iphone的拍照功能和打开闪光灯，有些代码我也不太理解，很多是在网上借鉴其他人的。IOS有两种的拍照和视频的方式：1.直接使用UIImagePickerController，这个类提供了一个简单便捷的拍照与选择图片库里图片的功能。2.另一种是通过AVFoundation.framework框架完全自定义拍照的界面和选择图片库界面。我只做了第一种，就先给大家介绍第一种做法：
一、首先调用接口前，我们需要先判断当前设备是否支持UIImagePickerController，用isSourceTypeAvailable:来判断是否可用
二、查看符合的媒体类型，这个时候我们调用availableMediaTypeForSourceType：判断
在调用UIImagePickerController时我们需要加入他的两个代理方法：
UINavigationControllerDelegate和UIImagePickerControllerDelegate，在调用摄像头的时候还可以调闪光灯，一会代码里有。
要调用闪光灯需要先建一个AVCaptureSession类的实例对象:
//
// Created by Mason on 13-1-23.
// Copyright (c) 2013年 Mason. All rights reserved.
//

#import
//调用闪光灯调用框架
#import

@interface CameraViewController : UIViewController
{
AVCaptureSession * _AVSession;//调用闪光灯的时候创建的类
}

@property(nonatomic,retain)AVCaptureSession * AVSession;

@end
在.m的- (void)viewDidLoad里建立4Button，Camera调用相机、Library调用图片库、flashlight打开闪光灯、close关闭闪光灯
//打开相机
-(void)addCarema
{
//判断是否可以打开相机，模拟器此功能无法使用
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

UIImagePickerController * picker = [[UIImagePickerController alloc]init];
picker.delegate = self;
picker.allowsEditing = YES; //是否可编辑
//摄像头
picker.sourceType = UIImagePickerControllerSourceTypeCamera;
[self presentModalViewController:picker animated:YES];
[picker release];
}else{
//如果没有提示用户
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"你没有摄像头" delegate:nil cancelButtonTitle:@"Drat!" otherButtonTitles:nil];
[alert show];
}
}
打开相机后，然后需要调用UIImagePickerControllerDelegate里的方法，拍摄完成后执行的方法和点击Cancel之后执行的方法：
//拍摄完成后要执行的方法
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
//得到图片
UIImage * image = [info objectForKey:UIImagePickerControllerOriginalImage];
//图片存入相册
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
[self dismissModalViewControllerAnimated:YES];

}
//点击Cancel按钮后执行方法
-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
[self dismissModalViewControllerAnimated:YES];
}
调用相机照片和保存到图片库已经完成。
接着介绍打开照片库：
-(void)openPicLibrary
{
//相册是可以用模拟器打开的
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {
UIImagePickerController * picker = [[UIImagePickerController alloc]init];
picker.delegate = self;
picker.allowsEditing = YES;//是否可以编辑

//打开相册选择照片
picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
[self presentModalViewController:picker animated:YES];
[picker release];
}else{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"你没有摄像头" delegate:nil cancelButtonTitle:@"Drat!" otherButtonTitles:nil];
[alert show];
}

}

//选中图片进入的代理方法
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(NSDictionary *)editingInfo
{
[self dismissModalViewControllerAnimated:YES];
}
调用闪光灯的代码，由于我也不是很理解，所以没法加注释，但是已经亲测可用，但是调闪光灯时有一个算是bug吧，闪光灯会闲一下，然后再一直亮
-(void)openFlashlight
{
AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if (device.torchMode == AVCaptureTorchModeOff) {
//Create an AV session
AVCaptureSession * session = [[AVCaptureSession alloc]init];

// Create device input and add to current session
AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
[session addInput:input];

// Create video output and add to current session
AVCaptureVideoDataOutput * output = [[AVCaptureVideoDataOutput alloc]init];
[session addOutput:output];

// Start session configuration
[session beginConfiguration];
[device lockForConfiguration:nil];

// Set torch to on
[device setTorchMode:AVCaptureTorchModeOn];

[device unlockForConfiguration];
[session commitConfiguration];

// Start the session
[session startRunning];

// Keep the session around
[self setAVSession:self.AVSession];

[output release];
}
}

-(void)closeFlashlight
{
[self.AVSession stopRunning];
[self.AVSession release];
}