Ios 如何在Objective-C中将PHAsset转换为UIImage
我有一个填充了Ios 如何在Objective-C中将PHAsset转换为UIImage,ios,objective-c,iphone,arrays,uiimage,Ios,Objective C,Iphone,Arrays,Uiimage,我有一个填充了PHAsset对象()的数组,我想知道如何将它们转换为UIImage,然后将它们保存在数组中 带有PHAsset对象的数组被称为self.assets,以下是我目前掌握的内容: PHImageManager *manager = [PHImageManager defaultManager]; CGFloat scale = UIScreen.mainScreen.scale; NSMutableArray *images = [NSMutableArray arrayWith
PHAsset
对象()的数组,我想知道如何将它们转换为UIImage,然后将它们保存在数组中
带有PHAsset对象的数组被称为self.assets
,以下是我目前掌握的内容:
PHImageManager *manager = [PHImageManager defaultManager];
CGFloat scale = UIScreen.mainScreen.scale;
NSMutableArray *images = [NSMutableArray arrayWithCapacity:[self.assets count]];
for (int i = 0; i < [self.assets count]; i++) {
CGSize targetSize = CGSizeMake(scale, scale);
[manager requestImageForAsset:[self.assets objectAtIndex:i]
targetSize:targetSize
contentMode:PHImageContentModeAspectFill
options:self.requestOptions
resultHandler:^(UIImage *image, NSDictionary *info){
[images addObject:image];
}];
}
在viewDidLoad中,我正在这样做:
self.requestOptions = [[PHImageRequestOptions alloc] init];
self.requestOptions.resizeMode = PHImageRequestOptionsResizeModeExact;
self.requestOptions.deliveryMode = PHImageRequestOptionsDeliveryModeHighQualityFormat;
但在进行一些调试之后,我一直看到self.assets
具有以下值:
(
<PHAsset: 0x1743828a0> 3B6D658D-EC76-43A1-9793-35D889E9CF15/L0/001 mediaType=1/0, assetSource=3, (2448x2448), creationDate=2015-07-27 02:02:46 +0000, location=1, hidden=0, favorite=0 ,
<PHAsset: 0x174382970> 50F05575-71D2-446B-BD1E-8E3250E375AD/L0/001 mediaType=1/0, assetSource=3, (2448x2448), creationDate=2015-07-27 02:02:47 +0000, location=1, hidden=0, favorite=0
)
(
3B6D658D-EC76-43A1-9793-35D889E9CF15/L0/001 mediaType=1/0,assetSource=3,(2448x2448),creationDate=2015-07-27 02:02:46+0000,location=1,hidden=0,favorite=0,
50F05575-71D2-446B-BD1E-8E3250E375AD/L0/001媒体类型=1/0,资产来源=3,(2448x2448),创建日期=2015-07-27 02:02:47+0000,位置=1,隐藏=0,收藏=0
)
而
图像
为空。有人知道如何将相位集添加到UIImages中,并将其添加到images
数组中吗?感谢您的帮助。谢谢 对于像我一样在这个问题上苦苦挣扎的人来说,这是一条路要走
首先将requestOptions设置为:
self.requestOptions = [[PHImageRequestOptions alloc] init];
self.requestOptions.resizeMode = PHImageRequestOptionsResizeModeExact;
self.requestOptions.deliveryMode = PHImageRequestOptionsDeliveryModeHighQualityFormat;
// this one is key
self.requestOptions.synchronous = YES;
如果在一个填充了PHAsset对象的数组中有多个资源,则添加以下代码:
self.assets = [NSMutableArray arrayWithArray:assets];
PHImageManager *manager = [PHImageManager defaultManager];
NSMutableArray *images = [NSMutableArray arrayWithCapacity:[assets count]];
// assets contains PHAsset objects.
__block UIImage *ima;
for (PHAsset *asset in self.assets) {
// Do something with the asset
[manager requestImageForAsset:asset
targetSize:PHImageManagerMaximumSize
contentMode:PHImageContentModeDefault
options:self.requestOptions
resultHandler:^void(UIImage *image, NSDictionary *info) {
ima = image;
[images addObject:ima];
}];
}
现在,images
数组包含uiimage
格式的所有图像。swift3.0答案
let photoAsset = asset
let manager = PHImageManager.default()
var options: PHImageRequestOptions?
options = PHImageRequestOptions()
options?.resizeMode = .exact
options?.isSynchronous = true
manager.requestImage(
for: photoAsset,
targetSize: PHImageManagerMaximumSize,
contentMode: .aspectFill,
options: options
) { [weak self] result, _ in
completion(result)
}
选项?.isSynchronous=true非常重要
BOOL synchronous; // return only a single result, blocking until available (or failure). Defaults to NO
图像可能为零(很少)。最好进行评估,否则数组add nil将使应用程序崩溃
if(image){
ima = image;
[images addObject:ima];
}
Swift 4.2
extension PHAsset {
var image : UIImage {
var thumbnail = UIImage()
let imageManager = PHCachingImageManager()
imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { image, _ in
thumbnail = image!
})
return thumbnail
}
}
let image = asset.image
这个代码不起作用!通过resultHandler返回的UIImage*图像始终为零。给这个人一个cookie。requestOptions.synchronous=YES;这修复了我在请求资产时的神秘错误<代码>[Generic]创建类型未知的图像格式时出错代码>**isSynchronous**如果为false(默认值),requestImage(for:targetSize:contentMode:options:resultHandler:)方法将立即返回。根据deliveryMode属性的不同,Photos可能会在方法返回之前调用resultHandler块,或者稍后调用,或者两者都调用。如果为true,requestImage(for:targetSize:contentMode:options:resultHandler:)方法将阻止调用线程,直到映像数据准备就绪或发生错误。Photos只调用一次结果处理程序块。>注意:仅从后台线程执行同步请求。
extension PHAsset {
var image : UIImage {
var thumbnail = UIImage()
let imageManager = PHCachingImageManager()
imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { image, _ in
thumbnail = image!
})
return thumbnail
}
}
let image = asset.image