javascript - CORDOVA 文件插件未捕获类型错误 : Illegal constructor

Question

我正在尝试使用 cordova 文件插件编写一个文件，以下示例来自 https://www.neontribe.co.uk/cordova-file-plugin-examples/

这是我的代码:

var errorHandler = function (fileName, e) {  
        var msg = '';

        switch (e.code) {
            case FileError.QUOTA_EXCEEDED_ERR:
                msg = 'Storage quota exceeded';
                break;
            case FileError.NOT_FOUND_ERR:
                msg = 'File not found';
                break;
            case FileError.SECURITY_ERR:
                msg = 'Security error';
                break;
            case FileError.INVALID_MODIFICATION_ERR:
                msg = 'Invalid modification';
                break;
            case FileError.INVALID_STATE_ERR:
                msg = 'Invalid state';
                break;
            default:
                msg = 'Unknown error';
                break;
        };

    console.log('Error (' + fileName + '): ' + msg);
}

function writeToFile(fileName, data) {
    data = JSON.stringify(data, null, '\t');
    window.resolveLocalFileSystemURL(cordova.file.dataDirectory, function (directoryEntry) {
        directoryEntry.getFile(fileName, { create: true }, function (fileEntry) {
            fileEntry.createWriter(function (fileWriter) {
                fileWriter.onwriteend = function (e) {
                    // for real-world usage, you might consider passing a success callback
                    console.log('Write of file "' + fileName + '"" completed.');
                };

                fileWriter.onerror = function (e) {
                    // you could hook this up with our global error handler, or pass in an error callback
                    console.log('Write failed: ' + e.toString());
                };

                var blob = new Blob([data], { type: 'text/plain' });
                fileWriter.write(blob);
            }, errorHandler.bind(null, fileName));
        }, errorHandler.bind(null, fileName));
    }, errorHandler.bind(null, fileName));
}

writeToFile('example.json', { foo: 'bar' });

错误:

Error in Success callbackId: File681009815 : SyntaxError: Unexpected end of input:312

Uncaught SyntaxError: Unexpected end of input:314

Error in Success callbackId: File681009817 : TypeError: Illegal constructor:312

Uncaught TypeError: Illegal constructor:314

知道代码有什么问题吗？

谢谢， 菲利普

Answer 1

我猜您正在 Android 4.x 上测试此功能。我在 Android 4.2.2 上也遇到了同样的问题。

首先，注释掉platforms/android/platform_ww/cordova.js中的try{}catch{}第 289,312-314 行，了解代码失败的确切行。它可能会在var blob = new Blob([data], { type: 'text/plain' });中

尝试在不使用 Blob() 的情况下直接将数据写入 FileWriter :

带有 Blob

var blob = new Blob([data], { type: 'text/plain' });
fileWriter.write(blob);

没有 Blob

fileWriter.write(data);

native api 写入一个字符串，因此只要您写入文本，它就应该起作用: https://github.com/apache/cordova-plugin-file/blob/master/src/android/FileUtils.java#L1129

另外，我会检查您尝试写入的数据是否正确，主要是通过以下错误:

Unexpected end of input

最后，这个解决方案可能与这个问题有关: https://stackoverflow.com/a/15302872/1786341