如何在Rikulo中使用Cordova / Phonegap文件系統API？

Question

請執行我的英語...我最初嘗試為Android platfrom編寫跨平台Web應用程序。 我必須將文件寫入和讀取到手機的文件系統。 我已經看到軟件包rikulo_gap本身不支持Filesystem API。 Rikulo使用的Fileystem API就是其中一個 ，它當然不適用於移動平台。

因此，我已經看到Rikulo的Js-Package應該使我的Dart-Code與我的Cordova.js-File（v4.0.0）可以互操作，其中包括全局函數requestFileSystem（persistence，size，success-funct，fail-funct）。 現在我試圖使我的代碼正常工作，但是我沒有找回文件系統-我遇到了錯誤...

這是我的Dart代碼：

import 'package:rikulo_gap/device.dart';
import 'dart:js' as js;

void main() { 
 Device.init().then((device) => onDeviceReady(device)).
 catchError((ex) => print("AN ERROR OCCURED: " + ex.toString()));
}

void onDeviceReady(device) {
 var persistent = js.context['PERSISTENT']; 
 print("Should be Constant PERSISTENT of LFS: " + persistent.toString());
 var fsName = js.context.callMethod('requestFileSystem',[persistent,0,dofs,fail]);
}

void dofs(fs) {
 print("Success");
 var myFs = js.context[fs];
 print("The Return of RequestFileSystem is a: " + myFs.toString());
}

LogCat說：

10-23 18:08:32.589: D/CordovaLog(951): file:///android_asset/www/adam.dart.js: Line 12111 : Should be Constant PERSISTENT of LFS: 1
10-23 18:08:32.624: D/CordovaLog(951): file:///android_asset/www/adam.dart.js: Line 12111 : Success
10-23 18:08:32.649: D/CordovaLog(951): file:///android_asset/www/cordova.js: Line 1060 : processMessage failed: Stack: Error
10-23 18:08:32.649: D/CordovaLog(951):     at dart.wrapException (file:///android_asset/www/adam.dart.js:2520:15)
10-23 18:08:32.649: D/CordovaLog(951):     at JsObject.$index (file:///android_asset/www/adam.dart.js:11549:17)
10-23 18:08:32.649: D/CordovaLog(951):     at dart.J.$index$asx (file:///android_asset/www/adam.dart.js:19278:41)
10-23 18:08:32.649: D/CordovaLog(951):     at dofs (file:///android_asset/www/adam.dart.js:4185:7)
10-23 18:08:32.649: D/CordovaLog(951):     at dart.Primitives_applyFunction (file:///android_asset/www/adam.dart.js:2489:23)
10-23 18:08:32.649: D/CordovaLog(951):     at _callDartFunction (file:///android_asset/www/adam.dart.js:11464:29)
10-23 18:08:32.649: D/CordovaLog(951):     at file:///android_asset/www/adam.dart.js:11671:18
10-23 18:08:32.649: D/CordovaLog(951):     at file:///android_asset/www/plugins/org.apache.cordova.file/www/requestFileSystem.js:52:25
10-23 18:08:32.649: D/CordovaLog(951):     at success (file:///android_asset/www/plugins/org.apache.cordova.file/www/fileSystems-roots.js:40:13)
10-23 18:08:32.649: D/CordovaLog(951):     at Object.cordova.callbackFromNative (file:///android_asset/www/cordova.js:293:54)
10-23 18:08:32.649: D/CordovaLog(951): file:///android_asset/www/cordova.js: Line 1061 : processMessage failed: Message: S01 File1158866550 [{"fullPath":"\/","filesystemName":"temporary","isDirectory":true,"nativeURL":"file:\/\/\/storage\/emulated\/0\/Android\/data\/de.htwg.myAndroid\/cache\/","filesystem":0,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"persistent","isDirectory":true,"nativeURL":"file:\/\/\/storage\/emulated\/0\/","filesystem":1,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"content","isDirectory":true,"nativeURL":"cdvfile:\/\/localhost\/content\/","filesystem":1,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"files","isDirectory":true,"nativeURL":"file:\/\/\/data\/data\/de.htwg.myAndroid\/files\/","filesystem":1,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"files-external","isDirectory":true,"nativeURL":"file:\/\/\/storage\/emulated\/0\/Android\/data\/de.htwg.myAndroid\/files\/","filesystem":1,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"documents","isDirectory":true,"nativeURL":"file:\/\/\/data\/data\/de.htwg.myAndroid\/files\/Documents\/","filesystem":1,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"sdcard","isDirectory":true,"nativeURL":"file:\/\/\/storage\/emulated\/0\/","filesystem":1,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"cache","isDirectory":true,"nativeURL":"file:\/\/\/data\/data\/de.htwg.myAndroid\/cache\/","filesystem":1,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"cache-external","isDirectory":true,"nativeURL":"file:\/\/\/storage\/emulated\/0\/Android\/data\/de.htwg.myAndroid\/cache\/","filesystem":1,"isFile":false,"name":""},{"fullPath":"\/","filesystemName":"root","isDirectory":true,"nativeURL":"file:\/\/\/","filesystem":1,"isFile":false,"name":""}]       

令我煩惱的是，堆棧上的第一個異常是dart.wrapException，所以我想這是一個常見的Dart <> Js Interop問題。

我遵循了Cordova使用Android構建的官方說明，目前我正在使用cordova run android的Windows CommandLine構建。 （是的，我已經安裝了插件（通過命令行安裝File，FileUtil，Device，並將它們添加到項目中）。

所以有人可以告訴我：

1. 就像我想的那樣，並且沒有將Ridova / Dart使用cordova-Filesystem API的通用方法嗎？
2. 如果1.為真，是否有解決方法？ 有人有一個主意，一個零星的筆記或其他可以幫助我的東西嗎？

Answer 1

1. Rikulo還不支持Cordova文件系統API。 您可以貢獻一個，也可以嘗試使用window.requestFileSystem。

2. 返回到dofs的對象是JsObject實例，因此您無需使用js.context進行轉換。 那是，

    var myFs = js.context[fs]; 

   應修訂為

    var myFs = fs; 

Answer 2

omG，您到了第2點的地方就這么對了……浪費了我兩天的時間：O（第1點無法正常工作，因為使用dart：html程序包，函數window.requestFileSystem調用了webKitRequestFileSystem，該功能僅在chrome瀏覽器和LogCat告訴我類似“不支持功能webKitRequestFileSystem）

我很生氣，因為fs.toString剛返回了[Object object]，所以我認為它只是一個空對象，並且因為我只使用了dofs（fs）（無類型）對函數進行了簽名，所以我的IDE / Dart-API沒有給出我為JsObject提出了諸如“ callMethod（）”之類的建議...現在我以這種方式進行了更改：

void main() {
 Device.init().then((device) => onDeviceReady(device)).catchError((ex) => print("AN ERROR OCCURED: " + ex.toString()));
}
void onDeviceReady(device) {
 var persistent = context['PERSISTENT']; 
 print("Should be Constant PERSISTENT of LFS: " + persistent.toString());
 context.callMethod('requestFileSystem',[persistent,0,dofs,fail]);
}
void dofs(JsObject fs) {
 print("Success");
 var fsroot = fs['root'];
 createFile(fsroot);
}
void createFile(JsObject fsroot) {
 var cNe = new JsObject.jsify({'create': true, 'exclusive': false});
 fsroot.callMethod('getFile', ["DartCreatedFile.txt",cNe,gotFileEntry,fail]);
}
void gotFileEntry(JsObject fileEntry) {
 print(fileEntry['fullPath']);
}

Logcat成功地告訴我：

10-24 14:17:03.945: D/CordovaLog(6685): file:///android_asset/www/fileSystemApi.js: Line 8 : Device is Ready!!!
10-24 14:17:04.055: D/CordovaLog(6685): file:///android_asset/www/adam.dart.js: Line 12294 : Should be Constant PERSISTENT of LFS: 1
10-24 14:17:04.085: D/CordovaLog(6685): file:///android_asset/www/adam.dart.js: Line 12294 : Success
10-24 14:17:04.105: D/CordovaLog(6685): file:///android_asset/www/adam.dart.js: Line 12294 : //DartCreatedFile.txt