从内部存储编辑文件 [英] edit file from internal storage

问题描述

如何编辑Android应用程序内部存储中文件的内容.

How can I edit the content of a file located on the internal storage in my Android app.

我要擦除整个内容，然后再次写入文件，而不是将数据附加到当前内容.

I want to erase the whole content and then write to the file again, instead of appending data to the current content.

这是我的读写代码:

package com.example.cargom;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.content.Context;


public class FileManager {

    FileOutputStream outputStream;
    FileInputStream inputStream;

    public void writeToFile(Context context, String fileName, String data) {
        try {
            outputStream = context.openFileOutput(fileName, Context.MODE_PRIVATE);
            outputStream.write(data.getBytes());
            outputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public String readFromFile(Context context, String fileName) {
        String data = "";
        int c;

        try {
            inputStream = context.openFileInput(fileName);
            while ((c = inputStream.read()) != -1) {
                data = data + Character.toString((char) c);
            }
            inputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return data;
    }
}

推荐答案

您的课程已经在执行您要求的工作了.它首先擦除文件的内容，然后在其上写入.为了进一步了解，

Your class is already doing what you rquire. It first erases the contents of the file and then writes on it. For further understanding,

当您使用 MODE_PRIVATE 启动流时，第二次尝试写入文件时，文件中已有的内容将被删除并写入新内容.

When you initiate your stream with MODE_PRIVATE, the second time when you try to write the file, the contents that are already in the file gets erased and the new contents are written.

    outputStream = context.openFileOutput(fileName, Context.MODE_PRIVATE);

当您使用 MODE_APPEND 时，已经存在的内容将保留下来，新内容将被追加到文件中.

When you use MODE_APPEND, the contents that are already there stays and the new contents will be appended to the file.

    outputStream = context.openFileOutput(fileName, Context.MODE_APPEND);

有关处理内部存储中文件的更多参考信息和详细知识，我建议您观看以下三个简短的视频，为您提供有关演示的详细说明.

For more reference and detailed knowledge on dealing with files in Internal storage, I recommend you to watch the below three short videos which gives you detailed description with demo.

http://www.youtube.com/watch?v = Jswr6tkv8ro& index = 4& list = PLonJJ3BVjZW5JdoFT0Rlt3ry5Mjp7s8cT http://www.youtube.com/watch?v=cGxHphBjTBk&; index = 5& list = PLonJJ3BVjZW5JdoFT0Rlt3ry5Mjp7s8cT http://www.youtube.com/watch?v=mMcrj_To18k&; index = 6& list = PLonJJ3BVjZW5JdoFT0Rlt3ry5Mjp7s8cT

希望有帮助！还有其他问题，请在下面评论.

Hope it helps! Any more questions, please comment below.

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