数据存储之文件存储

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package com.example.twelve;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.FileWriter;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.text.TextUtils;import android.widget.EditText;import android.widget.Toast;/** * @author HD * @date 2015-12-7 * @package_name com.example.twelve * @file_name MainActivity.java */public class MainActivity extends Activity {    private EditText etTest;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        etTest = (EditText) findViewById(R.id.etTest);        String content = load();        if(!TextUtils.isEmpty(content)){            etTest.setText(content);            etTest.setSelection(content.length());            Toast.makeText(MainActivity.this, "恢复数据成功", Toast.LENGTH_SHORT).show();        }    }    @Override    protected void onDestroy() {        // TODO 自动生成的方法存根        super.onDestroy();        String etContent = etTest.getText().toString();        save(etContent);    }    private void save(String content){        FileOutputStream fileOutputStream = null;        BufferedWriter bufferedWriter =null;        try {            fileOutputStream = openFileOutput("etContent", Context.MODE_PRIVATE);            bufferedWriter = new BufferedWriter(new OutputStreamWriter(fileOutputStream));            bufferedWriter.write(content);        } catch (FileNotFoundException e) {            // TODO 自动生成的 catch 块            e.printStackTrace();        } catch (IOException e) {            // TODO 自动生成的 catch 块            e.printStackTrace();        }finally{            if(bufferedWriter != null){                try {                    bufferedWriter.close();                } catch (IOException e) {                    // TODO 自动生成的 catch 块                    e.printStackTrace();                }            }        }    }    private String load(){        String line = "";        FileInputStream fileInputStream = null;        BufferedReader bufferedReader = null;        StringBuilder content = new StringBuilder();        try {            fileInputStream = MainActivity.this.openFileInput("etContent");            bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));            while((line = bufferedReader.readLine()) != null){                content.append(line);            }        } catch (FileNotFoundException e) {            // TODO 自动生成的 catch 块            e.printStackTrace();        } catch (IOException e) {            // TODO 自动生成的 catch 块            e.printStackTrace();        }finally{            if(bufferedReader != null){                try {                    bufferedReader.close();                } catch (IOException e) {                    // TODO 自动生成的 catch 块                    e.printStackTrace();                }            }        }        return content.toString();    }}

<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="com.example.twelve.MainActivity" >    <EditText         android:id="@+id/etTest"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="please input your name"/></RelativeLayout>

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.twelve"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="14"        android:targetSdkVersion="21" />    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name=".MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

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