filereader | 易学教程

Example for file read/write with NSFileHandle

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问题 Are there good examples for doing file read/write in chunks with objective c? I am new to objective-c and iPhone API, here is the sample code that I wrote. Are there better ways to do it? -(void) performFileOperation { @try { NSFileHandle *inputFileHandle; NSFileHandle *outputFileHandle; //check whether the output file exist, if not create a new one. NSFileManager *morphedFileManager; outputFileManager = [NSFileManager defaultManager]; if ([outputFileManager fileExistsAtPath: self

Reading and writing to a server-side file in AngularJS

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问题 I'm attempting to create a simple guestbook with AngularJS, and read and write the names to a simple file. Trouble is, I can't seem to get my code to even read from the file. This is my directory structure: This is index.html: <!DOCTYPE html> <html ng-app> <head> <meta charset="ISO-8859-1"> <title>GuestBook</title> <script src="http://code.angularjs.org/angular-1.0.0rc3.min.js"></script> <script type="text/javascript" src="javascript/user.js"></script> </head> <body> <h1>Welcome!</h1> <div ng

Resolving IOException, FileNotFoundException when using FileReader

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问题 I've not been able to resolve the following exception in the code below. What is the problem with the way I use BufferedReader? I'm using BufferedReader inside the main method OUTPUT :- ParseFileName.java:56: unreported exception java.io.FileNotFoundException; must be caught or declared to be thrown BufferedReader buffread = new BufferedReader (new FileReader("file.txt")); // ParseFileName is used to get the file name from a file path // For eg: get - crc.v from "$ROOT/rtl/..path/crc.v"

Reading a file created by the media capture plugin in Cordova - Creating Thumbnails

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问题 Big picture here is that I'm trying to get a photo gallery working for a large number of photos. Currently I'm using the raw URL of the images as gallery thumbnails, which is incredibly slow and crashes older devices quickly. I'd like to create a thumbnail of each photo that is taken with my app's camera and store these either locally or on a backend database. However, I haven't found a good solution. I tried the thumbnailer plugin here but my build failed after installation. I think this

Determining the last file chunk

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I'm trying to setup a file upload through rest for large files. The function below is taking care of chunking but I need to be able to recognize the last chunk because my rest call changes to /finishUpload() in order to commit the save. Right now I'm only able to figure out when the blob is empty but I can't figure out how to determine the last iteration before the blob is empty. This is the script I'm using below to parse my files. export default function parseFile(file, options) { var opts = typeof options === 'undefined' ? {} : options; var fileSize = file.size; var chunkSize = typeof opts[

Failed to load resource: net::ERR_FILE_NOT_FOUND uploading files bigger than 500Mb

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I have a problem uploading files bigger than 500Mb. I created a plunker file with error code: https://plnkr.co/edit/vKHNkUuVX1RrMcZ6Ezhc?p=preview var request = new XMLHttpRequest(); request.open("POST", "/uploadFile"); request.send(formData); request.addEventListener("progress", function(evt) { if (evt.lengthComputable) { console.log(evt.loaded / evt.total); } else { console.log('Undefined percent...'); } }, false); request.addEventListener("load", function(evt) { console.error(evt); }, false); request.addEventListener("error", function(evt) { console.error(evt); }, false); To reproduce the

PhoneGap FileReader/readAsDataURL Not Triggering Callbacks

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I am using PhoneGap Build to build an iOS v7.1+ application and using weinre to debug. I am using the media-capture plugin and file API to capture a video in an attempt get its base64 representation. I can get the video recorder to open, take a video, and return the file path. I then use resolveLocalFileSystemURL() to get a file object which readAsDataURL() requires. The problem is FileReader is never calling the onloadend callback. I have been poking around all day. Putting console.log() 's everywhere I could think of. I checked to make sure the iOS version is supported . Every variable is

JavaScript for loop on files FileReader

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The problem is breaking my mind. Can someone help me? In the <script> tag in my html file I have this: window.ondragover = function(e){return false;} window.ondragenter = function(e){return false;} window.ondrop = function(e){ var files = e.target.files || e.dataTransfer.files; for (var i = 0, file; file = files[i];i++){ var img = document.createElement('img'); img.height = 200; img.width = 200; img.style.background = 'grey'; document.body.appendChild(img); var reader = new FileReader(); reader.onload = function(){ img.src = reader.result; } reader.readAsDataURL(file); } return false; } but

Google HTML5训练营：图片旋转墙

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六月末，第一次去参加Google的HTML5训练营，估计其他同学多少都接触过。从下午一点到晚上10点，将近9个小时的时间里，首先由杜欢、寒蕊、胡坤做了一些技术上的分享，我对Google工程师寒蕊MM的CSS 3D Transforms内容比较感兴趣，在后面选择命题的时候，选择做一个图片展示的东东，最后命名：图片旋转墙。我们最后合作的成员有：韦益，方有亮，邓佑华，姜志超，乔杰，盛庆鸿，冯尚实（自己），大家都来自不同的公司，为了一种兴趣跟爱好，来这里相聚，收获都挺多。我们讨论技术实施方案，最后确定用Drag&Drop实现本地图片拖拽，用File API 跟FileReader API实现文件的读取，再用寒蕊MM分享的3D Transforms进行图片旋转展示。也是根据实施方案，我们把7个人分成3组，分别领取三块任务，因为时间较紧，所以最后的作品也比较粗糙，只是实现了基本功能。猛击这里查看效果： http://enjoyhtml5.com/hackathons/20110626/photo-gallery/index.html （用Chrome 12+打开）这里我只详细讲我完成的部分：Drag&Drop 以及File API 、FileReader API这两块内容。一、 Drag&Drop事件 dragstart ：拖拽元素开始拖拽时触发，触发对象：拖拽元素； dragenter

Understanding how BufferedReader works in Java

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问题 Very basic question on how BufferedReader works. Given the string/phrase, I want to find and print it from the file with a lot of text in it. using BufferedReader in Java I did some research on this topic and that was the closest result. Not quite addressing my problem though. So with this information, why does the following code terminate? public class MainApp { String line = null; String phrase = "eye"; try { File file = new File("text.txt"); FileReader fr = new FileReader(file);