2

如何获取 fileDoesNotExist 回调的变量、url 和名称:

window.checkIfFileExists = function(path, url, name) {
  return window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, (function(fileSystem) {
    return fileSystem.root.getFile(path, {
      create: false
    }, fileExists, fileDoesNotExist);
  }), getFSFail);
};

fileDoesNotExist = (fileEntry, url, name) ->
  downloadImage(url, name)
4

2 回答 2

2

phoneGap的getFile函数有两个回调函数。您在这里犯的错误fileDoesNotExist是它应该调用两个函数,而不是引用一个变量。

像下面这样的东西会起作用:

window.checkIfFileExists = function(path, url, name) {
  return window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, (function(fileSystem) {
    return fileSystem.root.getFile(path, {
      create: false
    }, 
    function(e) {
      //this will be called in case of success
    },
    function(e) {
      //this will be called in case of failure
      //you can access path, url, name in here
    });
  }), getFSFail);
};
于 2013-03-22T14:07:18.733 回答
1

您可以传入一个匿名函数,并将它们添加到回调的调用中:

window.checkIfFileExists = function(path, url, name) {
  return window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, (function(fileSystem) {
    return fileSystem.root.getFile(path, {
      create: false
    }, fileExists, function(){
        //manually call and pass parameters
        fileDoesNotExist.call(this,path,url,name);
    });
  }), getFSFail);
};
于 2013-03-22T14:06:19.127 回答