UIWebView是iOS开发中常用的一个视图控件，多数情况下，它被用来显示HTML格式的内容。
iOS 6以上版本的Mobile Safari支持在网页中调用摄像头，只需要放置以下代码：
<input type = "file" capture = "camera" accept = "image/*" id = "cameraInput">
但是iOS 5的浏览器还不支持这个功能，如果需要调用摄像头，则依然需要通过Hybrid开发方式来实现。
代码如下：
#import "ViewController.h"
#import "NSData+Base64.h"
@interface UIWebViewCallCameraViewController ()
{
NSString *callback; // 定义变量用于保存返回函数
}
@end
@implementation UIWebViewCallCameraViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
// 设置delegate并载入html文件
self.webView.delegate = self;
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"camera" ofType:@"html"];
NSString *fileContent = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
[self.webView loadHTMLString:fileContent baseURL:nil];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
NSString *requestString = [[request URL] absoluteString];
NSString *protocol = @"js-call://"; //协议名称
if ([requestString hasPrefix:protocol]) {
NSString *requestContent = [requestString substringFromIndex:[protocol length]];
NSArray *vals = [requestContent componentsSeparatedByString:@"/"];
if ([[vals objectAtIndex:0] isEqualToString:@"camera"]) // 摄像头
{
callback = [vals objectAtIndex:1];
[self doAction:UIImagePickerControllerSourceTypeCamera];
}
else if([[vals objectAtIndex:0] isEqualToString:@"photolibrary"]) // 图库
{
callback = [vals objectAtIndex:1];
[self doAction:UIImagePickerControllerSourceTypePhotoLibrary];
}
else if([[vals objectAtIndex:0] isEqualToString:@"album"]) // 相册
{
callback = [vals objectAtIndex:1];
[self doAction:UIImagePickerControllerSourceTypeSavedPhotosAlbum];
}
else
{
[webView stringByEvaluatingJavaScriptFromString:@"alert('未定义/lwme.cnblogs.com');"];
}
return NO;
}
return YES;
}
- (void)doAction:(UIImagePickerControllerSourceType)sourceType
{
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
imagePicker.delegate = self;
if ([UIImagePickerController isSourceTypeAvailable:sourceType]) {
imagePicker.sourceType = sourceType;
} else {
UIAlertView *av = [[UIAlertView alloc] initWithTitle:@"照片获取失败" message:@"没有可用的照片来源" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
[av show];
return;
}
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
UIPopoverController *popover = [[UIPopoverController alloc] initWithContentViewController:imagePicker];
[popover presentPopoverFromRect:CGRectMake(self.view.bounds.size.width / 2, self.view.bounds.size.height / 3, 10, 10) inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
} else {
[self presentModalViewController:imagePicker animated:YES];
}
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
if ([[info objectForKey:UIImagePickerControllerMediaType] isEqualToString:@"public.image"])
{
// 返回图片
UIImage *originalImage = [info objectForKey:UIImagePickerControllerOriginalImage];
// 设置并显示加载动画
UIAlertView *av = [[UIAlertView alloc] initWithTitle:@"正在处理图片..." message:@"\n\n"
delegate:self
cancelButtonTitle:nil
otherButtonTitles:nil, nil];
UIActivityIndicatorView *loading = [[UIActivityIndicatorView alloc]
initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
loading.center = CGPointMake(139.5, 75.5);
[av addSubview:loading];
[loading startAnimating];
[av show];
// 在后台线程处理图片
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
// 这里可以对图片做一些处理，如调整大小等，否则图片过大显示在网页上时会造成内存警告
// 图片转换成base64字符串
NSString *base64 = [UIImagePNGRepresentation(originalImage) base64Encoding];
[self performSelectorOnMainThread:@selector(doCallback:) withObject:base64 waitUntilDone:NO]; // 把结果显示在网页上
[av dismissWithClickedButtonIndex:0 animated:YES];
});
}
[picker dismissModalViewControllerAnimated:YES];
}
- (void)doCallback:(NSString *)data
{
[self.webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"%@('%@');", callback, data]];
}
@end
