如何使用科尔多瓦文件传输下载 base 64 图像

Posted 2023-03-07

【中文标题】如何使用科尔多瓦文件传输下载 base 64 图像

【英文标题】：How to download base 64 image using cordova filetransfer

【发布时间】：2016-02-20 05:25:26

【问题描述】：

我使用了cordova文件传输协议，并使用了下载功能来下载base-64图像。当我将远程服务器路径设置为“https://upload.wikimedia.org/wikipedia/commons/4/4a/Logo_2013_Google.png”时，它会下载，但是当我将 base-64 图像 pah 放在文件路径上时，它不会下载。 我不知道 base-64 转换。请帮忙。

----我的代码在下面----

  function download()
        var imageData = image.src;
        imageData = imageData.replace('data:image/png;base64,', '');

        var d = new Date();
        var imageName = "sample" + d.getTime() + ".png";

        //var filepath = encodeURI("https://upload.wikimedia.org/wikipedia/commons/4/4a/Logo_2013_Google.png");
        var filepath = encodeURI(imageData);

        window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, function (fileSystem) 
            fileSystem.root.getFile(imageName,  create: true, exclusive: true , function (fileEntry) 
                // get the full path to the newly created file on the device
                var localPath = fileEntry.fullPath;

                // massage the path for android devices (not tested)
                if (device.platform === "Android" && localPath.indexOf("file://") === 0) 
                    localPath = localPath.substring(7);
                

                // download the remote file and save it
                var remoteFile = filepath;
                var fileTransfer = new FileTransfer();
                fileTransfer.download(remoteFile, localPath, function (newFileEntry) 
                    // successful download, continue to the next image
                    console.log('successful download');
                ,
                function (error)  // error callback for #download
                    console.log('Error with #download method.', error);
                );
            );
        )

    )

提前致谢。

【参考方案1】：

我找到了自己问题的解决方案。

首先，我已将 base64 图像转换为文件流，并使用 web 服务在服务器上创建图像并在服务器上上传图像，并获取该服务器路径并使用 cordova 文件传输下载。

我的代码在下面

=> 将base64图像转换为图像的Web服务代码

string strImg = imageData.imageData;
   string fullName = "d:\\uploadimages";
   FileStream fs = new FileStream(fullName, FileMode.Create);
   BinaryWriter bw = new BinaryWriter(fs);

   byte[] data = Convert.FromBase64String(strImg);

   bw.Write(data);
   bw.Close();

=> 在手机上下载图片

function download()

    var filepath = encodeURI("http://www.telerik.com/sfimages/default-source/logos/app_builder.png"),
    window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, function (fileSystem) 
                fileSystem.root.getFile("sample.jpg",  create: true, exclusive: false , function (fileEntry) 

                    // get the full path to the newly created file on the device
                    var localPath = fileEntry.fullPath;

                    // massage the path for android devices (not tested)
                    if (device.platform === "Android" && localPath.indexOf("file://") === 0) 
                        localPath = localPath.substring(7);
                    

                    // download the remote file and save it
                    var remoteFile = filepath;
                    //loadingOverlay.displayLoading("Image will be save on your device.");

                    var fileTransfer = new FileTransfer();
                    fileTransfer.download(remoteFile, localPath, function (newFileEntry) 
                        // successful download, continue to the next image
                        var dwnldImagePath = newFileEntry.fullPath;
                        console.log('successful download');

                    ,
                    function (error)  // error callback for #download
                        console.log('Error with #download method.', error);

                    );
                );
                function(error)  // error callback for #getFile
                    console.log('Error with #getFile method.', error);
                );

            )