| --- |
| license: Licensed to the Apache Software Foundation (ASF) under one |
| or more contributor license agreements. See the NOTICE file |
| distributed with this work for additional information |
| regarding copyright ownership. The ASF licenses this file |
| to you under the Apache License, Version 2.0 (the |
| "License"); you may not use this file except in compliance |
| with the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, |
| software distributed under the License is distributed on an |
| "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| KIND, either express or implied. See the License for the |
| specific language governing permissions and limitations |
| under the License. |
| --- |
| |
| FileReader |
| ========== |
| |
| The `FileReader` allows basic access to a file. |
| |
| Properties |
| ---------- |
| |
| - __readyState__: One of the reader's three possible states, either `EMPTY`, `LOADING` or `DONE`. |
| - __result__: The contents of the file that have been read. _(DOMString)_ |
| - __error__: An object containing errors. _(FileError)_ |
| - __onloadstart__: Called when the read starts. _(Function)_ |
| - __onload__: Called when the read has successfully completed. _(Function)_ |
| - __onabort__: Called when the read has been aborted. For instance, by invoking the `abort()` method. _(Function)_ |
| - __onerror__: Called when the read has failed. _(Function)_ |
| - __onloadend__: Called when the request has completed (either in success or failure). _(Function)_ |
| |
| __NOTE:__ The following porperty is not supported: |
| |
| - __onprogress__: Called while reading the file, reporting progress in terms of `progress.loaded`/`progress.total`. _(Function)_ |
| |
| Methods |
| ------- |
| |
| - __abort__: Aborts reading file. |
| - __readAsDataURL__: Read file and return data as a base64-encoded data URL. |
| - __readAsText__: Reads text file. |
| - __readAsBinaryString__: Reads file as binary and returns a binary string. |
| - __readAsArrayBuffer__: Reads file as an `ArrayBuffer`. |
| |
| Details |
| ------- |
| |
| The `FileReader` object offers a way to read files from the device's |
| file system. Files can be read as text or as a base64 data-encoded |
| string. Event listeners receive the `loadstart`, `progress`, `load`, |
| `loadend`, `error`, and `abort` events. |
| |
| Supported Platforms |
| ------------------- |
| |
| - Android |
| - BlackBerry WebWorks (OS 5.0 and higher) |
| - iOS |
| - Windows Phone 7 and 8 |
| - Windows 8 |
| |
| Read As Data URL |
| ---------------- |
| |
| __Parameters:__ |
| |
| - __file__: the file object to read. |
| |
| Quick Example |
| ------------- |
| |
| function win(file) { |
| var reader = new FileReader(); |
| reader.onloadend = function (evt) { |
| console.log("read success"); |
| console.log(evt.target.result); |
| }; |
| reader.readAsDataURL(file); |
| }; |
| |
| var fail = function (evt) { |
| console.log(error.code); |
| }; |
| |
| entry.file(win, fail); |
| |
| Read As Text |
| ------------ |
| |
| __Parameters:__ |
| |
| - __file__: the file object to read. |
| - __encoding__: the encoding to use to encode the file's content. Default is UTF8. |
| |
| Quick Example |
| ------------- |
| |
| function win(file) { |
| var reader = new FileReader(); |
| reader.onloadend = function (evt) { |
| console.log("read success"); |
| console.log(evt.target.result); |
| }; |
| reader.readAsText(file); |
| }; |
| |
| var fail = function (evt) { |
| console.log(error.code); |
| }; |
| |
| entry.file(win, fail); |
| |
| Abort Quick Example |
| ------------------- |
| |
| function win(file) { |
| var reader = new FileReader(); |
| reader.onloadend = function(evt) { |
| console.log("read success"); |
| console.log(evt.target.result); |
| }; |
| reader.readAsText(file); |
| reader.abort(); |
| }; |
| |
| function fail(error) { |
| console.log(error.code); |
| } |
| |
| entry.file(win, fail); |
| |
| Full Example |
| ------------ |
| |
| <!DOCTYPE html> |
| <html> |
| <head> |
| <title>FileReader 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 |
| // |
| function onLoad() { |
| 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", null, gotFileEntry, fail); |
| } |
| |
| function gotFileEntry(fileEntry) { |
| fileEntry.file(gotFile, fail); |
| } |
| |
| function gotFile(file){ |
| readDataUrl(file); |
| readAsText(file); |
| } |
| |
| function readDataUrl(file) { |
| var reader = new FileReader(); |
| reader.onloadend = function(evt) { |
| console.log("Read as data URL"); |
| console.log(evt.target.result); |
| }; |
| reader.readAsDataURL(file); |
| } |
| |
| function readAsText(file) { |
| var reader = new FileReader(); |
| reader.onloadend = function(evt) { |
| console.log("Read as text"); |
| console.log(evt.target.result); |
| }; |
| reader.readAsText(file); |
| } |
| |
| function fail(evt) { |
| console.log(evt.target.error.code); |
| } |
| |
| </script> |
| </head> |
| <body> |
| <h1>Example</h1> |
| <p>Read File</p> |
| </body> |
| </html> |
| |
| iOS Quirks |
| ---------- |
| - The __encoding__ parameter is not supported, and UTF8 encoding is always in effect. |
| |
| Read As Binary String |
| --------------------- |
| |
| Currently supported on iOS and Android only. |
| |
| __Parameters:__ |
| |
| - __file__: the file object to read. |
| |
| Quick Example |
| ------------- |
| |
| function win(file) { |
| var reader = new FileReader(); |
| reader.onloadend = function (evt) { |
| console.log("read success"); |
| console.log(evt.target.result); |
| }; |
| reader.readAsBinaryString(file); |
| }; |
| |
| var fail = function (evt) { |
| console.log(error.code); |
| }; |
| |
| entry.file(win, fail); |
| |
| Read As Array Buffer |
| -------------------- |
| |
| Currently supported on iOS and Android only. |
| |
| __Parameters:__ |
| |
| - __file__: the file object to read. |
| |
| Quick Example |
| ------------- |
| |
| function win(file) { |
| var reader = new FileReader(); |
| reader.onloadend = function (evt) { |
| console.log("read success"); |
| console.log(new Uint8Array(evt.target.result)); |
| }; |
| reader.readAsArrayBuffer(file); |
| }; |
| |
| var fail = function (evt) { |
| console.log(error.code); |
| }; |
| |
| entry.file(win, fail); |
