Question

是否可以在创建的文件上设置侦听器，并在文件大小达到某个值时发出警报。

Answer 1

是和否。有一个名为FileObserver的类，它允许您侦听某些事件，例如在打开，关闭或修改文件时。文件大小没有特定的侦听器，但MODIFY或CLOSE_WRITE - 事件都适合。

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简短的例子：

observer = new FileObserver(pathToFile,MODIFY + CLOSE_WRITE)
     @Override
     public void onEvent(int event, String file) {
         Log.d(TAG, "File changed[" + pathToWatch + file + "]");
         //TODO: check file size...
     }
 };
 observer.startWatching();

Answer 2

您可以按如下方式检查文件大小更改。

在首选项或其他存储位置保存当前文件大小
创建文件的监听器
每当触发时，将文件大小与预先存储的大小进行比较

curFileSize = fileObject.length();  //size should be stored


  // creating listener
fileObserver = new FileObserver(pathToFile,MODIFY + CLOSE_WRITE)
  @Override
 public void onEvent(int event, String file) {
      //checking size
      if(curFileSize != fileObject.length())
        {
          //there is some change
        }
 }
};
observer.startWatching();

Answer 3

      double bytes = fileobj.length();
      double kilobytes = (bytes / 1024);
      double megabytes = (kilobytes / 1024);

// you can find File size like above....
//if you are Writing a file via output writer you can also check in between file writing Process....that file writer reached at certain Size !!!

Android检查文件大小是否超过某个值

3 个答案: