如何在IBM Worklight中使用FileSystem API寫入文件？
[英]How to write in file using FileSystem API with IBM Worklight?
問題描述
我正在使用HTML5的FileSystem API和Worklight創建緩存文件JSON格式，我創建到文件時沒有任何問題，問題是當我嘗試向創建的文件中添加一些文本時，我使用了fileWriter但它沒有寫任何東西。
這是我開發的更新功能：
function update(fileName){
function onInitFs(fs) {
fs.root.getFile(fileName, {create: true}, function(fileEntry) {
// Create a FileWriter object for our FileEntry .
fileEntry.createWriter(function(fileWriter) {
fileWriter.onwriteend = function(e) {
console.log('Write completed.');
};
fileWriter.onerror = function(e) {
console.log('Write failed: ' + e.toString());
};
// Create a new Blob and write it to log.txt.
var blob = new Blob(['Lorem Ipsum'], {type: 'text/plain'});
fileWriter.write(blob);
}, errorHandler);
}, errorHandler);
}
window.requestFileSystem(window.PERSISTENT, 1024*1024, onInitFs, errorHandler);
function errorHandler(e) {
var msg = '';
switch (e.code) {
case FileError.QUOTA_EXCEEDED_ERR:
msg = 'QUOTA_EXCEEDED_ERR';
break;
case FileError.NOT_FOUND_ERR:
msg = 'NOT_FOUND_ERR';
break;
case FileError.SECURITY_ERR:
msg = 'SECURITY_ERR';
break;
case FileError.INVALID_MODIFICATION_ERR:
msg = 'INVALID_MODIFICATION_ERR';
break;
case FileError.INVALID_STATE_ERR:
msg = 'INVALID_STATE_ERR';
break;
default:
msg = 'Unknown Error';
break;
};
document.querySelector('#example-list-fs-ul').innerHTML = 'Error: ' + msg;
}
}
這是用於顯示文件內容的read函數，它返回一個空的String：
function read(fileName){
function onInitFs(fs) {
fs.root.getFile(fileName, {}, function(fileEntry) {
// Get a File object representing the file,
// then use FileReader to read its contents.
fileEntry.file(function(file) {
var reader = new FileReader();
reader.onloadend = function(e) {
alert(this.result);
};
reader.readAsText(file);
}, errorHandler);
}, errorHandler);
}
window.requestFileSystem(window.PERSISTENT, 1024*1024, onInitFs, errorHandler);
}
任何人都有任何想法如何解決此問題以及如何成功寫入和讀取文件？
謝謝
2 個解決方案
解決方案2
0 2014-06-02 14:23:05
這是一個允許創建/編輯/讀取/刪除簡單文本文件的示例。 希望這可以幫助。
<!DOCTYPE HTML>
<html>
<head>
<meta charset="UTF-8">
<title>CordovaApp</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=0">
<!--
<link rel="shortcut icon" href="images/favicon.png">
<link rel="apple-touch-icon" href="images/apple-touch-icon.png">
-->
<link rel="stylesheet" href="css/main.css">
<script>window.$ = window.jQuery = WLJQ;</script>
<script type="text/javascript" charset="utf-8">
/**
* Function called when page has finished loading.
*/
function init(){
console.log("onDeviceReady");
}
onWLReady = function() {
// Wait for PhoneGap to load
document.addEventListener("deviceready", init, false);
}
function createFile() {
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0,
function(fileSystem) {
fileSystem.root.getFile("readme.txt", {create: true, exclusive: false},
function(fileEntry) {
fileEntry.createWriter(
function(writer) {
writer.onwriteend = function(evt) {
log("File created...");
};
writer.onwritestart = function(evt){
log("onwritestart");
};
writer.onwrite = function(evt){
log("onwrite");
};
writer.onerror = function(evt){
log("onerror");
};
writer.write("File created at: " + new Date().toLocaleString());
},
fail);
}
, fail);
},
fail);
}
function editFile() {
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0,
function(fileSystem) {
fileSystem.root.getFile("readme.txt", {create: false, exclusive: false},
function(fileEntry) {
fileEntry.createWriter(
function(writer) {
writer.onwriteend = function(evt) {
log("File edited");
};
writer.onwritestart = function(evt){
log("onwritestart");
};
writer.onwrite = function(evt){
log("onwrite");
};
writer.onerror = function(evt){
log("onerror");
};
writer.seek(writer.length);
writer.write("<br>File edited at: " + new Date().toLocaleString());
},
fail);
}
, fail);
},
fail);
}
function readFile() {
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0,
function(fileSystem) {
fileSystem.root.getFile("readme.txt", {
create : false
},
function(fileEntry){
fileEntry.file(function(file) {
readDataUrl(file);
readAsText(file);
},
fail);
},
fail);
}, fail);
}
function readDataUrl(file){
var reader = new FileReader();
log("readDataUrl...");
reader.onloadstart = function(evt){
log("onloadstart: " + evt.target.result);
};
reader.onload = function(evt){
log("onload: " + evt.target.result);
};
reader.onloadend = function(evt){
log("onloadend: " + evt.target.result);
};
reader.onerror = function(evt){
log("onerror: " + evt.target.result);
};
reader.readAsDataURL(file);
reader.abort();
}
function readAsText(file){
var reader = new FileReader();
log("readAsText...");
reader.onloadstart = function(evt){
log("onloadstart: " + evt.target.result);
};
reader.onload = function(evt){
log("onload: " + evt.target.result);
};
reader.onloadend = function(evt){
log("onloadend: " + evt.target.result);
};
reader.onerror = function(evt){
log("onerror: " + evt.target.result);
};
reader.readAsText(file);
}
function deleteFile() {
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0,
function(fileSystem) {
fileSystem.root.getFile("readme.txt", {
create : false
},
function(fileEntry){
fileEntry.remove(function() {log("File deleted.");
},
fail);
},
fail);
}, fail);
}
function fail(error){
var msg = error;
switch(error.code)
{
case FileError.NOT_FOUND_ERR:
msg = "File Not Found";
break;
case FileError.SECURITY_ERR:
msg = "Security Error";
break;
case FileError.ABORT_ERR:
msg = "Abort error";
break;
case FileError.NOT_READABLE_ERR:
msg = "Not Readable";
break;
case FileError.ENCODING_ERR:
msg = "Encoding Error";
break;
case FileError.NO_MODIFICATION_ALLOWED_ERR:
msg = "No Modification Allowed";
break;
case FileError.INVALID_STATE_ERR:
msg = "Invalid State";
break;
case FileError.SYNTAX_ERR:
msg = "Syntax Error";
break;
case FileError.INVALID_MODIFICATION_ERR:
msg = "Invalid Modification Error";
break;
case FileError.QUOTA_EXCEEDED_ERR:
msg = "Quota Exceeded";
break;
case FileError.TYPE_MISMATCH_ERR:
msg = "Type Mismatch Error";
break;
case FileError.PATH_EXISTS_ERR:
msg = "Path Already Exists Error";
break;
}
log("fail: "+ msg);
}
function log(info){
document.getElementById('log').innerHTML += "<br>" + info;
}
function clearLog(info){
document.getElementById('log').innerHTML = "";
}
</script>
</head>
<body style="display: none;">
<!--application UI goes here-->
<div>
<button onclick="createFile();">Create File</button><br>
<button onclick="editFile();">Edit File</button><br>
<button onclick="readFile();">Read File</button><br>
<button onclick="deleteFile();">Delete File</button><br>
<button onclick="clearLog();">Clear Log</button><br>
</div>
<script src="js/initOptions.js"></script>
<script src="js/main.js"></script>
<script src="js/messages.js"></script>
<div><u><b>Log:</b></u></div>
<div id=log></div>
</body>
</html>
請注意，Javascript方法最好放在js / main.js中，而不是在html文件中定義。 對於我來說，將工作樣本作為單個文件提供起來更容易。
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