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As object that allows you to create and write data to a file.
INIT
, WRITING
, or DONE
.The following property is not supported:
progress.loaded
/progress.total
. (Function) MethodsThe FileWriter
object offers a way to write UTF-8 encoded files to the device file system. Applications respond to writestart
, progress
, write
, writeend
, error
, and abort
events.
Each FileWriter
corresponds to a single file, to which data can be written many times. The FileWriter
maintains the file's position
and length
attributes, which allow the app to seek
and write
anywhere in the file. By default, the FileWriter
writes to the beginning of the file, overwriting existing data. Set the optional append
boolean to true
in the FileWriter
's constructor to write to the end of the file.
Text data is supported by all platforms listed below. Text is encoded as UTF-8 before being written to the filesystem. Some platforms also support binary data, which can be passed in as either an ArrayBuffer or a Blob.
Text and Binary Support:
Text-only Support:
function win(writer) { // fast forwards file pointer to end of file writer.seek(writer.length); }; var fail = function(evt) { console.log(error.code); }; entry.createWriter(win, fail);
function win(writer) { writer.truncate(10); }; var fail = function(evt) { console.log(error.code); }; entry.createWriter(win, fail);
function win(writer) { writer.onwrite = function(evt) { console.log("write success"); }; writer.write("some sample text"); }; var fail = function(evt) { console.log(error.code); }; entry.createWriter(win, fail);
function win(writer) { var data = new ArrayBuffer(5), dataView = new Int8Array(data); for (i=0; i < 5; i++) { dataView[i] = i; } writer.onwrite = function(evt) { console.log("write success"); }; writer.write(data); }; var fail = function(evt) { console.log(error.code); }; entry.createWriter(win, fail);
function win(writer) { writer.onwrite = function(evt) { console.log("write success"); }; writer.seek(writer.length); writer.write("appended text"); }; var fail = function(evt) { console.log(error.code); }; entry.createWriter(win, fail);
function win(writer) { writer.onwrite = function(evt) { console.log("write success"); }; writer.write("some sample text"); writer.abort(); }; var fail = function(evt) { console.log(error.code); }; entry.createWriter(win, fail);
<!DOCTYPE html> <html> <head> <title>FileWriter Example</title> <script type="text/javascript" charset="utf-8" src="cordova-x.x.x.js"></script> <script type="text/javascript" charset="utf-8"> // Wait for device API libraries to load // document.addEventListener("deviceready", onDeviceReady, false); // device APIs are available // function onDeviceReady() { window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, gotFS, fail); } function gotFS(fileSystem) { fileSystem.root.getFile("readme.txt", {create: true, exclusive: false}, gotFileEntry, fail); } function gotFileEntry(fileEntry) { fileEntry.createWriter(gotFileWriter, fail); } function gotFileWriter(writer) { writer.onwriteend = function(evt) { console.log("contents of file now 'some sample text'"); writer.truncate(11); writer.onwriteend = function(evt) { console.log("contents of file now 'some sample'"); writer.seek(4); writer.write(" different text"); writer.onwriteend = function(evt){ console.log("contents of file now 'some different text'"); } }; }; writer.write("some sample text"); } function fail(error) { console.log(error.code); } </script> </head> <body> <h1>Example</h1> <p>Write File</p> </body> </html>