java - 将多个字符串写入文件而不删除浏览器的第一个 ANDROID Collection 夹

Question

我正在为学校制作一个简单的浏览器，我正在尝试制作 Collection 夹。此处的代码将 Collection 夹添加到文件中(这样我可以在应用程序关闭后保留它)并将其显示在 TextView 中。我的问题是它只能保存一个。如果我添加第二个，第一个将被替换。我想我可以将它们添加到数组或数组列表中(或任何有效的东西，我愿意接受建议)，但我无法成功。感谢您的帮助。

 package com.example.browser3;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Favorite extends Activity {
EditText etName;
EditText etAdress;
Button bAdd;
TextView tvDisplay;




protected void onResume() {
    readFile("favorite.txt", tvDisplay);
    super.onResume();
}

public void writeFile(String fileName, EditText v, EditText x){

    try {
        OutputStreamWriter out=new OutputStreamWriter(openFileOutput(fileName,0));
        out.write(v.getText().toString()+ x.getText().toString());

        out.close();
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public void readFile(String fileName, TextView w){
    try {
        InputStream in=openFileInput(fileName);
        if(in!=null){
            InputStreamReader reader= new InputStreamReader(in);
            BufferedReader buffreader= new BufferedReader(reader);

            StringBuilder builder= new StringBuilder();
            String str;
            while((str=buffreader.readLine())!=null){
                builder.append(str+ "\n");
            }
            in.close();
            w.setText(builder.toString());
        }
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.favorite);


    etName = (EditText) findViewById(R.id.etName);
    etAdress = (EditText) findViewById(R.id.etAdress);
    bAdd = (Button) findViewById(R.id.bAdd);
    tvDisplay = (TextView) findViewById(R.id.tvDisplay);

    bAdd.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            writeFile("favorite.txt",etName, etAdress);
            readFile("favorite.txt", tvDisplay);
        }

    });

}
}

Answer 1

要写在第一个位置，即前置，那么你需要使用它

     private void writeToFile(Context context,String data){
         try{
             String path=context.getFilesDir().getAbsolutePath();

             File file = new File(path + File.separator + fileName);
             RandomAccessFile rf = new RandomAccessFile(file,"rws"); 
             file.getParentFile().mkdirs();
                Log.d("creating file path",path);

                byte[] text = new byte[(int) file.length()];
                rf.readFully(text);
                rf.seek(0);
                rf.writeBytes(data);
                rf.write(text);
                Log.d("write","writing file...");
                rf.close();




         }catch(Exception e){e.printStackTrace(); Log.d("caught", "data wititng fail");} 
     }

如果你想追加使用这个

     private void writeToFile(Context context,String data){
         try{
             String path=context.getFilesDir().getAbsolutePath();

             File file = new File(path + File.separator + fileName);
             RandomAccessFile rf = new RandomAccessFile(file,"rws"); 
             file.getParentFile().mkdirs();
                Log.d("creating file path",path);

                byte[] text = new byte[(int) file.length()];
                rf.readFully(text);
                rf.seek(0);
                 rf.write(text);
                rf.writeBytes(data);

                Log.d("write","writing file...");
                rf.close();                     


         }catch(Exception e){e.printStackTrace(); Log.d("caught", "data wititng fail");} 
     }

或者你可以在MODE_APPEND模式下打开文件..以追加模式打开文件更改为此OutputStreamWriter out=new OutputStreamWriter(openFileOutput(fileName,true));