<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.itheima28.writedata"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="8"

android:targetSdkVersion="19" />

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<activity

android:name="com.itheima28.writedata.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>

<LinearLayout 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:orientation="vertical"

tools:context=".MainActivity">

<Button

android:id="@+id/btn_read_private"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="读私有文件" />

<Button

android:id="@+id/btn_write_private"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="写私有文件" />

<Button

android:id="@+id/btn_read_readable"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="读可读文件" />

<Button

android:id="@+id/btn_write_readable"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="写可读文件" />

<Button

android:id="@+id/btn_read_writeable"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="读可写文件" />

<Button

android:id="@+id/btn_write_writeable"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="写可写文件" />

<Button

android:id="@+id/btn_read_readable_writeable"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="读可读可写文件" />

<Button

android:id="@+id/btn_write_readable_writeable"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="写可读可写文件" />

</LinearLayout>

package com.itheima28.writedata;

import java.io.BufferedReader;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.InputStreamReader;

import android.content.Context;

import android.os.Bundle;

import android.support.v7.app.ActionBarActivity;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Toast;

/**

* 读写文件

* 注意可以将写文件和写文件的两个功能分别写到不同的项目中进行测试

* @author toto

*/

public class MainActivity extends ActionBarActivity implements OnClickListener{

//这个路径是文件所在路径

private String basicPath = "/data/data/com.itheima28.writedata/files/";

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

// 写数据

// 私有文件

writeToLocal("private.txt", Context.MODE_PRIVATE);

// 可读文件

writeToLocal("readable.txt", Context.MODE_WORLD_READABLE);

// 可写文件

writeToLocal("writeable.txt", Context.MODE_WORLD_WRITEABLE);

// 可读可写文件

writeToLocal("readable_writeable.txt", Context.MODE_WORLD_READABLE

+ Context.MODE_WORLD_WRITEABLE);

findViewById(R.id.btn_read_private).setOnClickListener(this);

findViewById(R.id.btn_write_private).setOnClickListener(this);

findViewById(R.id.btn_read_readable).setOnClickListener(this);

findViewById(R.id.btn_write_readable).setOnClickListener(this);

findViewById(R.id.btn_read_writeable).setOnClickListener(this);

findViewById(R.id.btn_write_writeable).setOnClickListener(this);

findViewById(R.id.btn_read_readable_writeable).setOnClickListener(this);

findViewById(R.id.btn_write_readable_writeable).setOnClickListener(this);

}

/**

* 写文件

* @param fileName

* @param mode

*/

private void writeToLocal(String fileName, int mode) {

try {

FileOutputStream fos = openFileOutput(fileName, mode);

fos.write(("第一个程序写的数据：" + fileName).getBytes());

fos.flush();

fos.close();

} catch (Exception e) {

e.printStackTrace();

}

}

/**

* 哪一个控件被点击, v对象就代表被点击的对象

*/

@Override

public void onClick(View v) {

switch (v.getId()) {

case R.id.btn_read_private:

readFile("private.txt");

break;

case R.id.btn_write_private:

writeFile("private.txt");

break;

case R.id.btn_read_readable:

readFile("readable.txt");

break;

case R.id.btn_write_readable:

writeFile("readable.txt");

break;

case R.id.btn_read_writeable:

readFile("writeable.txt");

break;

case R.id.btn_write_writeable:

writeFile("writeable.txt");

break;

case R.id.btn_read_readable_writeable:

readFile("readable_writeable.txt");

break;

case R.id.btn_write_readable_writeable:

writeFile("readable_writeable.txt");

break;

default:

break;

}

}

/**

* 读文件

* @param fileName

*/

private void readFile(String fileName) {

try {

String path = basicPath + fileName;

BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(path)));

String text = reader.readLine();

reader.close();

Toast.makeText(this, "读取成功: " + text, 0).show();

} catch (Exception e) {

e.printStackTrace();

Toast.makeText(this, "读取失败: " + fileName, 0).show();

}

}

/**

* 写文件

* @param fileName

*/

private void writeFile(String fileName) {

try {

String path = basicPath + fileName;

FileOutputStream fos = new FileOutputStream(path);

fos.write("哈哈, 被我给黑了".getBytes());

fos.flush();

fos.close();

Toast.makeText(this, "写入成功: " + fileName, 0).show();

} catch (Exception e) {

e.printStackTrace();

Toast.makeText(this, "写入失败: " + fileName, 0).show();

}

}

}