Android开发之文件存储

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Android系统实现数据持久化有三种，1,文件存储，2,SharedPreference,3,数据库存储

将数据存储到文件中，4.2之后有两个参数，一个是覆盖，一个是追加
MODE_PRIVATE MODE_APPEND

界面布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >    <EditText        android:id="@+id/edit"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="Type something here"        /></RelativeLayout>

主活动代码

package com.example.filepersistencetest;import java.io.BufferedWriter;import java.io.FileOutputStream;import java.io.IOException;import java.io.OutputStreamWriter;import android.os.Bundle;import android.app.Activity;import android.content.Context;import android.view.Menu;import android.widget.EditText;public class MainActivity extends Activity {    private EditText edit;    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        edit=(EditText)findViewById(R.id.edit);    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.main, menu);        return true;    }    protected void onDestroy(){        super.onDestroy();        String inputText=edit.getText().toString();        save(inputText);    }    public void save(String inputText)    {        FileOutputStream out=null;        BufferedWriter writer=null;        try{            out=openFileOutput("data",Context.MODE_PRIVATE);            writer=new BufferedWriter(new OutputStreamWriter(out));            writer.write(inputText);        }catch(IOException e)        {            e.printStackTrace();        }finally{            try{                if(writer!=null)                {writer.close();}            }catch(IOException e){                e.printStackTrace();            }        }    }}

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