read-write | 易学教程

Read and Write permission for storage and gallery usage for marshmallow

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问题 I am developing an android app in which it is required to provide permission for Read and write external storage. My requirement is to select a picture from gallery and use it in my app. Everything is working fine except Marshmallow devices. I want to provide permission for Marshmallow. Can anyone help me with this? 回答1: It can be achieved something as following... public class MainActivity extends AppCompatActivity implements ActivityCompat.OnRequestPermissionsResultCallback{ private static

Flushing fopen()'ed files opened in update mode,between read and write operations.Explicit flushing needed?

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I have read this about the switch between read and write operations(and vice-versa) for files opened for update using fopen() ( LINK ) "For files open for update (those which include a "+" sign), on which both input and output operations are allowed, the stream should be flushed (fflush) or repositioned (fseek, fsetpos, rewind) between either a writing operation followed by a reading operation or a reading operation which did not reach the end-of-file followed by a writing operation." There are two things mentioned here that I would like to highlight the stream should be flushed (fflush) or

How to read/write file with iOS, in simulator as well as on device?

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As I need to read a file when my app is launched and write it sometimes while using it, I tried to reach it with : NSString *dataFile = [[NSBundle mainBundle] pathForResource:@"data" ofType:@"txt"]; NSLog(@"%@",dataFile); And the file, that should be in my project folder, is instead in the simulator folder : 2012-06-13 17:36:56.398 MyFileApp[610:15203] /Users/Rob/Library/Application Support/iPhone Simulator/5.1/Applications/1FFD4436-DCCA-4280-9E47-F6474BEE0183/MyFileApp.app/myFile.txt So if I want to read/write it in using the simulator as well as the real device, what should I do ? Thanks for

Bash read/write file descriptors — seek to start of file

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I tried to use the read/write file descriptor in bash so that I could delete the file that the file descriptor referred to afterward, as such: F=$(mktemp) exec 3<> "$F" rm -f "$F" echo "Hello world" >&3 cat <&3 but the cat command gives no output. I can achieve what I want if I use separate file descriptors for reading and writing: F=$(mktemp) exec 3> "$F" exec 4< "$F" rm -f "$F" echo "Hello world" >&3 cat <&4 which prints Hello world . I suspected that bash doesn't automatically seek to the start of the file descriptor when you switch from writing to reading it, and the following combination

getting data from plist to NSMutableArray and writing the NSMutableArray to same plist iPhone

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问题 Using this code I am trying to get the data from Templates.plist file but I am getting null value in array. //from plist NSString *path = [[NSBundle mainBundle] pathForResource:@"Templates" ofType:@"plist"]; NSMutableArray *arry=[[NSMutableArray alloc]initWithContentsOfFile:path]; NSLog(@"arrayArray:::: %@", arry); This is my plist file: Also I want to know how can I add more strings to this plist file and delete a string from this plist. 回答1: First off you cannot write to anything in you

read and write to same socket (TCP) using select

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问题 We're writing a client and a server to do (what I thought was) pretty simple network communications. Mulitple clients connect to the server which then is supposed to send the data back to all other clients. The server just sits in a blocking select loop waiting for traffic, and when it comes, sends the data to the other clients. This seems to work just fine. The problem is the client. In response to a read, it will sometimes want to do a write. However, I've found that if I use: rv = select

Adding items to Swift array across multiple threads causing issues (because arrays aren't thread safe) - how do I get around that?

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I want to add given blocks to an array, and then run all the blocks contained in the array, when requested. I have code similar to this: class MyArrayBlockClass { private var blocksArray: Array<() -> Void> = Array() private let blocksQueue: NSOperationQueue() func addBlockToArray(block: () -> Void) { self.blocksArray.append(block) } func runBlocksInArray() { for block in self.blocksArray { let operation = NSBlockOperation(block: block) self.blocksQueue.addOperation(operation) } self.blocksQueue.removeAll(keepCapacity: false) } } The problem comes with the fact that addBlockToArray can be

How to access file included in app bundle in Swift?

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问题 I know there are a few questions pertaining to this, but they're in Objective-C. How can I access a .txt file included in my app using Swift on an actual iPhone ? I want to be able to read and write from it. Here are my project files if you want to take a look. I'm happy to add details if necessary. 回答1: Simply by searching in the app bundle for the resource var filePath = NSBundle.mainBundle().URLForResource("file", withExtension: "txt") However you can't write to it because it is in the app

Writing to stdin and reading from stdout (UNIX/LINUX/C Programming)

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I was working on an assignment where a program took a file descriptor as an argument (generally from the parent in an exec call) and read from a file and wrote to a file descriptor, and in my testing, I realized that the program would work from the command-line and not give an error if I used 0, 1 or 2 as the file descriptor. That made sense to me except that I could write to stdin and have it show on the screen. Is there an explanation for this? I always thought there was some protection on stdin/stdout and you certainly can't fprintf to stdin or fgets from stdout. #include <stdlib.h>

Reading/Writing MS Word files in Python

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Is it possible to read and write Word (2003 and 2007) files in Python without using a COM object? I know that I can: f = open('c:\file.doc', "w") f.write(text) f.close() but Word will read it as an HTML file not a native .doc file. auramo I'd look into IronPython which intrinsically has access to windows/office APIs because it runs on .NET runtime. Damian See python-docx , its official documentation is available here . This has worked very well for me. markling If you only what to read, it is simplest to use the linux soffice command to convert it to text, and then load the text into python: