Get selected file size using org.apache.cordova.file

问题

Using org.apache.cordova.file plugin I can selected the file and I get the native path of the file. After that I have to restrict the user to select the file according to there file size. But I can't get that file size. My problem is that I can't get the file Size using that plugin. For this I am using this tutorial.

回答1:

To get file size, you need to access it via metadata as follows:

            window.resolveLocalFileSystemURL(filePath, 
                function (fileSystem) {
                    fileSystem.getFile(fileName, {create: false}, 
                        function (fileEntry) {
                            fileEntry.getMetadata(
                                function (metadata) {
                                    alert(metadata.size); // get file size
                                }, 
                                function (error) {}
                            );
                        }, 
                        function (error) {}
                    );
                }, 
                function (error) {} 
            );     

回答2:

This code is a little more compact, as you don't need to call the getMetadata function, size is already a property of fileEntry

function gotPhoto(imageUri) {
    window.resolveLocalFileSystemURI(imageUri, 
        function(fileEntry) {
            fileEntry.file(function(fileObj) {
                console.log("Size = " + fileObj.size);
            },
            function (error) {});
        }, function (error) {}
    );
}

回答3:

The function window.resolveLocalFileSystemURI is deprecated and furthermore you may need to have a specific dedicated transparent function for it.

Therefore you can declare this function.

function getFileSize(fileUri) {
    return new Promise(function(resolve, reject) {    
        window.resolveLocalFileSystemURL(fileUri, function(fileEntry) {
            fileEntry.file(function(fileObj) {
                resolve(fileObj.size);
            },
            function(err){
                reject(err);
            });
        }, 
        function(err){
            reject(err);
        });
    });
}

and then merely use it like this

getFileSize("myFileUri").
  then(function(fileSize){
     console.log(fileSize);
  }).
  catch(function(err){
    console.error(err);
  });

来源：https://stackoverflow.com/questions/32858805/get-selected-file-size-using-org-apache-cordova-file