在中级篇里面，已经介绍过相册与拍照的简单使用了，那么接下来我们就来讲一讲它们的后续处理，到底应该怎么做才好呢
首先我们先来讲拍照
还是那个点击使用照片后调用的代理方法中，我们来做以下代码中所提到的事情
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
[picker dismissViewControllerAnimated:YES completion:NULL];
NSString *mediaType = [info valueForKey:UIImagePickerControllerMediaType];
UIImage *newImage;
WS(weakSelf);
if ([mediaType isEqualToString:@"public.image"]) {
UIImage *originImage = [info objectForKey:UIImagePickerControllerOriginalImage];
dispatch_sync(dispatch_get_global_queue(0, 0), ^{
[weakSelf saveImageToPhotos:originImage];
});
newImage = [self scaleImage:originImage toScale:0.1];
}
[_imageArray addObject:newImage];
}这个时候，从里面取出的图片是原图，毕竟尺寸、占用内存都比较大，我们需要进行剪切来优化它
-(UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize {
UIGraphicsBeginImageContext(CGSizeMake(image.size.width*scaleSize,image.size.height*scaleSize));
[image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height *scaleSize)];
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return scaledImage;
}当然了，原图我们也是需要保存到相册里面的，所以我们的保存方法如下
- (void)saveImageToPhotos:(UIImage *)savedImage {
UIImageWriteToSavedPhotosAlbum(savedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
NSString *message = nil;
if (error) {
message = @"保存失败";
} else {
message = @"保存成功";
[self getAssetsLastPhoto];
}
NSLog(@"%@", message);
}这就是拍照后续的使用了，如果还需要优化的话，那就要看你们的产品以及后台如何制定方案了
接下来我们来讲一讲相册吧
最常用的就是我们需要调用一个方法，将所有的照片都取出来，这里要注意的一点是，我们只要缩略图以及原图URL地址就可以了，因为它们两个还是比较重要的
- (void)loadAssets {
// Initialise
_assets = [NSMutableArray new];
_assetLibrary = [[ALAssetsLibrary alloc] init];
// Run in the background as it takes a while to get all assets from the library
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
NSMutableArray *assetGroups = [[NSMutableArray alloc] init];
NSMutableArray *assetURLDictionaries = [[NSMutableArray alloc] init];
// Process assets
void (^assetEnumerator)(ALAsset *, NSUInteger, BOOL *) = ^(ALAsset *result, NSUInteger index, BOOL *stop) {
if (result != nil) {
if ([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto]) {
[assetURLDictionaries addObject:[result valueForProperty:ALAssetPropertyURLs]];
NSURL *url = result.defaultRepresentation.url;
[_assetLibrary assetForURL:url
resultBlock:^(ALAsset *asset) {
if (asset) {
@synchronized(_assets) {
[_assets addObject:asset];
if (_assets.count == 1) {
// Added first asset so reload data
// [self.tableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO];
}
}
}
}
failureBlock:^(NSError *error){
NSLog(@"operation was not successfull!");
}];
}
}
};
// Process groups
void (^ assetGroupEnumerator) (ALAssetsGroup *, BOOL *) = ^(ALAssetsGroup *group, BOOL *stop) {
if (group != nil) {
[group enumerateAssetsWithOptions:NSEnumerationReverse usingBlock:assetEnumerator];
[assetGroups addObject:group];
}
};
// Process!
[self.assetLibrary enumerateGroupsWithTypes:ALAssetsGroupAll
usingBlock:assetGroupEnumerator
failureBlock:^(NSError *error) {
NSLog(@"There is an error");
}];
});
}在显示缩略图的地方，我们可以显示缩略图，而在显示原图的地方，我们也可以根据URL显示原图
@synchronized(_assets) {
NSMutableArray *copy = [_assets copy];
for (ALAsset *asset in copy) {
[photos addObject:[MWPhoto photoWithThumbImage:[UIImage imageWithCGImage:asset.thumbnail] URL:asset.defaultRepresentation.url]];
}
}上面的方法，就是加入原图的缩略图以及地址URL，这里我用了一个包含两个属性的类来添加，当然你也可以弄两个类来单独添加
另外在上传图片的时候还是需要对原图进行剪切，改变base64，当然还是要看你们服务器那边的方案
好啦，这就是我们对相册以及拍照的后处理咯
就写到这里吧，有什么问题，可以来群里找我哦
本文出自 “东软iOS校友群的技术博客” 博客，请务必保留此出处http://neusoftios.blog.51cto.com/9977509/1650050
原文：http://neusoftios.blog.51cto.com/9977509/1650050