Android数据持久化技术 — — —文件存储

文件保存

---

package com.example.datastroredtest;

import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;

import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;

public class MainActivity extends Activity {

    EditText username = null;
    EditText password = null;

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

        username = (EditText)findViewById(R.id.username);
        password = (EditText)findViewById(R.id.password);

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        String fileName ="data";
        String user_name = username.getText().toString();
        String pass_word = password.getText().toString();
        save(fileName,user_name,pass_word);
    }

    public void save(String fileName, String username, String password) {

        FileOutputStream fos = null;
        BufferedWriter writer = null;
        try{
            fos = openFileOutput(fileName,MODE_PRIVATE);
            writer = new BufferedWriter(new OutputStreamWriter(fos));
            writer.write("<username>");
            writer.write(username);
            writer.write("</username>");
            writer.write("\n");
            writer.write("<password>");
            writer.write(password);
            writer.write("</password>");

        }catch(IOException e){
            e.printStackTrace();
        }finally{
            try{
                if(writer != null){
                    writer.close();
                }
            }catch (IOException e){
                    e.printStackTrace();
            }
        }

    }
}

---

package com.example.datastroredtest;

import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class MainActivity extends Activity {

    EditText username = null;
    EditText password = null;

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

        username = (EditText)findViewById(R.id.username);
        password = (EditText)findViewById(R.id.password);

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        String fileName ="data";
        ArrayList<String> values = load(fileName);
        username.setText(values.get(0));
        password.setText(values.get(1));
    }

    public ArrayList<String> load(String fileName) {

        FileInputStream fis = null;
        BufferedReader reader = null;
        ArrayList<String> content = new ArrayList<String>();

        try{
            fis = openFileInput(fileName);
            reader = new BufferedReader(new InputStreamReader(fis));
            String line = null;
            while ((line = reader.readLine()) != null){
                    content.add(line);
            }

        }catch (IOException e){
            e.printStackTrace();
        }finally {
            try{
                if(reader != null){
                    reader.close();
                }
            }catch (IOException e){
                e.printStackTrace();
            }
        }

        return content;
    }
}