Xamarin/C# 中的 Android FileObserver 示例? [英] Android FileObserver example in Xamarin/C#?

问题描述

我需要在 Xamarin c# (Android) 中创建文件观察器的指导

I need guidance in creating a file observer in Xamarin c# (Android)

某种可行的例子会很棒！

Some sort of workable example would be wonderful !

我已经尝试将 java 转换为 C#，但由于我缺乏在 C# 环境中的经验，它在编译时抛出了太多错误......并且在 C# vs java 中获取编写参考代码被证明很烦人..

I've tried to convert the java ones over to C# but due to my lack on experience in the C# environment, it's throwing too many errors when being compiled .. and getting the write reference code within C# vs java is proving irritating ..

所以请！，可能有人在那里指点我一些可行的

So PLEASE !, may someone out there point me to some sort of workable

这是一个文件观察者的java例子https://gist.github.com/shirou/659180

This is a java example of a file observer https://gist.github.com/shirou/659180

推荐答案

创建一个继承自 的类Android.OS.FileObserver，你只需要实现OnEvent() 和 one(+) 构造函数.在你看过一次之后，它是一个非常简单的模式...... ;-)

Create a class that inherits from Android.OS.FileObserver, you only need to implement the OnEvent() and one(+) Constructors. Its a really simple pattern after you see it once... ;-)

注意事项:

• 在路径上观看，如果您需要按文件过滤，请在 OnEvent 中进行
• 不要让你的 FileObserver 对象被垃圾回收，否则你的 OnEvents 会神奇地停止 :-/
• 记得调用 StartWatching() 以接收 OnEvent 调用

• Watch on a path, if you need to filter by file, do it in the OnEvent
• Do not let your FileObserver object get GC'd or your OnEvents will magically stop :-/
• Remember to call StartWatching() in order to receive OnEvent calls

FileObserver 类:

using System;
using Android.OS;
using Android.Util;

namespace MyFileObserver
{
    public class MyPathObserver : Android.OS.FileObserver
    {
        static FileObserverEvents _Events = (FileObserverEvents.AllEvents);
        const string tag = "StackoverFlow";

        public MyPathObserver (String rootPath) : base(rootPath, _Events)
        {
            Log.Info(tag, String.Format("Watching : {0}", rootPath)); 
        }

        public MyPathObserver (String rootPath, FileObserverEvents events) : base(rootPath, events)
        {
            Log.Info(tag, String.Format("Watching : {0} : {1}", rootPath, events)); 
        }

        public override void OnEvent(FileObserverEvents e, String path)
        {
            Log.Info(tag, String.Format("{0}:{1}",path, e)); 
        }
    }
}

示例用法:

var pathToWatch = System.Environment.GetFolderPath (System.Environment.SpecialFolder.Personal);
// Do not let myFileObserver get GC'd, stash it's ref in an activty, or ...
myFileObserver = new MyPathObserver (pathToWatch);
myFileObserver.StartWatching (); // and StopWatching () when you are done...
var document = Path.Combine(pathToWatch, "StackOverFlow.txt");
button.Click += delegate {
    if (File.Exists (document)) {
        button.Text = "Delete File";
        File.Delete (document);
    } else {
        button.Text = "Create File";
        File.WriteAllText (document, "Foobar");
    }
};

adb logcat 输出(点击测试按钮时):

I/StackoverFlow( 3596): StackOverFlow.txt:Create
I/StackoverFlow( 3596): StackOverFlow.txt:Open
I/StackoverFlow( 3596): StackOverFlow.txt:Modify
I/StackoverFlow( 3596): StackOverFlow.txt:CloseWrite
I/StackoverFlow( 3596): StackOverFlow.txt:Delete
I/StackoverFlow( 3596): StackOverFlow.txt:Create
I/StackoverFlow( 3596): StackOverFlow.txt:Open
I/StackoverFlow( 3596): StackOverFlow.txt:Modify
I/StackoverFlow( 3596): StackOverFlow.txt:CloseWrite
I/StackoverFlow( 3596): StackOverFlow.txt:Delete
I/StackoverFlow( 3596): StackOverFlow.txt:Create
I/StackoverFlow( 3596): StackOverFlow.txt:Open
I/StackoverFlow( 3596): StackOverFlow.txt:Modify
I/StackoverFlow( 3596): StackOverFlow.txt:CloseWrite

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