小编Mah*_*vir的帖子

我在本地保存了一个M3U8文件。

我想从上面的文件下载视频文件。我怎样才能下载这个视频？

我正在尝试为本机做出反应.但每当我更新文件时,它都会出错

    enoent ENOENT: no such file or directory, open 'React Native/package.json'
npm WARN react-native@0.26.3 requires a peer of react@15.0.2 but none was installed.
npm WARN React Native No description
npm WARN React Native No repository field.
npm WARN React Native No README data
npm WARN React Native No license field.
   MacBook-Pro:React Native$ npm info react dist-tags.latest

请让我知道如何解决.

我开始安装反应原生.我已经成功安装了homebrew,nodejs,npm.但无法安装反应原生

首先我试过了

npm install -g react-native-cli

给我写警告:

Missing write access to /Users/project/.npm-packages/lib/node_modules/react-native-cli

之后我尝试过

sudo npm install -g react-native-cli

/Users/project/.npm-packages/bin/react-native -> /Users/project/.npm-packages/lib/node_modules/react-native-cli/index.js
/Users/project/.npm-packages/lib
??? react-native-cli@1.0.0

看起来像安装.

之后我尝试了

react-native init AwesomeProject

Error : react-native: command not found

可能是什么问题呢

我正在使用Unrar4iOS.Framework。它工作正常，但是当我添加-Objc其他链接器标志时。它给了我重复的错误。

    duplicate symbol __Z12CallbackProcjlll in:
    Library/Developer/Xcode/DerivedData/SARUnArchiveANY-fgljekydpkmvrlgapbahtfvvhsdl/Build/Intermediates/SARUnArchiveANY.build/Debug-iphonesimulator/SARUnArchiveANY.build/Objects-normal/x86_64/Unrar4iOS.o
    /My Project/SARUnArchiveANY-master/SARUnArchiveANY/vendor/Frameworks/Unrar4iOS.framework/Unrar4iOS(Unrar4iOS.o)
duplicate symbol _OBJC_IVAR_$_Unrar4iOS.header in:
    Library/Developer/Xcode/DerivedData/SARUnArchiveANY-fgljekydpkmvrlgapbahtfvvhsdl/Build/Intermediates/SARUnArchiveANY.build/Debug-iphonesimulator/SARUnArchiveANY.build/Objects-normal/x86_64/Unrar4iOS.o
    My Project/SARUnArchiveANY-master/SARUnArchiveANY/vendor/Frameworks/Unrar4iOS.framework/Unrar4iOS(Unrar4iOS.o)
duplicate symbol _OBJC_IVAR_$_Unrar4iOS.flags in:
    Library/Developer/Xcode/DerivedData/SARUnArchiveANY-fgljekydpkmvrlgapbahtfvvhsdl/Build/Intermediates/SARUnArchiveANY.build/Debug-iphonesimulator/SARUnArchiveANY.build/Objects-normal/x86_64/Unrar4iOS.o
    My Project/SARUnArchiveANY-master/SARUnArchiveANY/vendor/Frameworks/Unrar4iOS.framework/Unrar4iOS(Unrar4iOS.o)

我不得不添加use Objc标志以使用其他库。

我找到了很多将图像转换为纯黑白的代码。但没有这个工作。

我试过这段代码，但它把图像转换为灰度而不是黑白。

  -(UIImage *)convertOriginalImageToBWImage:(UIImage *)originalImage
{
    UIImage *newImage;
    CGColorSpaceRef colorSapce = CGColorSpaceCreateDeviceGray();
    CGContextRef context = CGBitmapContextCreate(nil, originalImage.size.width * originalImage.scale, originalImage.size.height * originalImage.scale, 8, originalImage.size.width * originalImage.scale, colorSapce, kCGImageAlphaNone);
    CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
    CGContextSetShouldAntialias(context, NO);
    CGContextDrawImage(context, CGRectMake(0, 0, originalImage.size.width, originalImage.size.height), [originalImage CGImage]);

    CGImageRef bwImage = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    CGColorSpaceRelease(colorSapce);

    UIImage *resultImage = [UIImage imageWithCGImage:bwImage];
    CGImageRelease(bwImage);

    UIGraphicsBeginImageContextWithOptions(originalImage.size, NO, originalImage.scale);
    [resultImage drawInRect:CGRectMake(0.0, 0.0, originalImage.size.width, originalImage.size.height)];
    newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();


    return newImage;
}

结果图像 -------------------------------------------> 预期图像

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