andorid 数据储存、SharedPreferences存储和手机内部储存

.xml

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

<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: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.hanqi.application3.DataActivity1"

    android:orientation="vertical">

    <EditText

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/et_1"

        android:hint="Key"/>

    <EditText

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/et_2"

        android:hint="Value"/>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content">

        <Button

            android:layout_width="0dp"

            android:layout_height="wrap_content"

            android:text="保存"

            android:layout_weight="1"

            android:onClick="bt1_onClick"/>

        <Button

            android:layout_width="0dp"

            android:layout_height="wrap_content"

            android:text="读取"

            android:layout_weight="1"

            android:onClick="bt2_onClick"/>

    </LinearLayout>

    <EditText

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/et_3"

        android:hint="要保存的内容"/>

    <EditText

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/et_4"

        android:hint="从文件中读取的内容"/>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content">

        <Button

            android:layout_width="0dp"

            android:layout_height="wrap_content"

            android:text="保存"

            android:layout_weight="1"

            android:onClick="bt3_onClick"/>

        <Button

            android:layout_width="0dp"

            android:layout_height="wrap_content"

            android:text="读取"

            android:layout_weight="1"

            android:onClick="bt4_onClick"/>

    </LinearLayout>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content">

        <Button

            android:layout_width="0dp"

            android:layout_height="wrap_content"

            android:text="保存文件"

            android:layout_weight="1"

            android:onClick="bt5_onClick"/>

        <Button

            android:layout_width="0dp"

            android:layout_height="wrap_content"

            android:text="读取文件"

            android:layout_weight="1"

            android:onClick="bt6_onClick"/>

    </LinearLayout>

    <ImageView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:src="@drawable/da1"

        android:id="@+id/iv_4"/>

</LinearLayout>

.java

package com.hanqi.application3;

import android.content.SharedPreferences;

import android.content.res.AssetManager;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

import android.view.View;

import android.widget.EditText;

import android.widget.ImageView;

import android.widget.Toast;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.io.PrintStream;

public class DataActivity1 extends AppCompatActivity {

    EditText et1;

    EditText et2;

    EditText et3;

    EditText et4;

    ImageView iv4;

    SharedPreferences sp;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_data1);

        et1=(EditText)findViewById(R.id.et_1);

        et2=(EditText)findViewById(R.id.et_2);

        et3=(EditText)findViewById(R.id.et_3);

        et4=(EditText)findViewById(R.id.et_4);

        iv4= (ImageView)findViewById(R.id.iv_4);

        //1.获取sp的实例，制定了文件名和操作模式   MODE_PRIVATE私有

        sp = getSharedPreferences("mydata",MODE_PRIVATE);

    }

    //操作assets内的文件

    public void bt5_onClick(View v)

    {

        //1.获取AssetManager

        AssetManager am = getAssets();

         try{

             //2.打开文件,获取输入流

             InputStream is = am.open("denglu.jpg");

             //3.获取输出流

             FileOutputStream fos2 = openFileOutput("denglu2.jpg",MODE_PRIVATE);

             //4.边度编写

             byte[] bb2 = new byte[1024];

             int ii2 = 0;

             while ((ii2 = is.read(bb2))>0)

             {

                 fos2.write(bb2,0,ii2);

             }

             fos2.close();

             is.close();

             Toast.makeText(DataActivity1.this, "保存成功", Toast.LENGTH_SHORT).show();

         }

         catch (Exception e)

         {

             e.printStackTrace();

             Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show();

         }

    }

    //从手机内部存储读图片文件

    public void bt6_onClick(View v)

    {

        //改变ImageView的图片来源，指向手机存储空间

        //1.获取文件存储的绝对路径

        String filepath = getFilesDir().getAbsolutePath();

        //2.组合完整路径

        filepath += "/denglu2.jpg";

        //3.生成位图实例

        Bitmap bm2 = BitmapFactory.decodeFile(filepath);

        //4.改变ImageView的图片来源

        iv4.setImageBitmap(bm2);

    }

    //文件名

    final String FILENAME = "test.txt";

    public void bt3_onClick(View v)

    {

        //1.获取要存储的内容

        String content = et3.getText().toString();

        //2.获取输出流

        try {

            FileOutputStream fos1 = openFileOutput(FILENAME, MODE_APPEND);

            //3.构造一个打印输出流

            PrintStream pm1 = new PrintStream(fos1);

            //4.写入内容

            pm1.println(content);

            pm1.close();

            fos1.close();

            Toast.makeText(DataActivity1.this, "保存成功", Toast.LENGTH_SHORT).show();

        } catch (Exception e) {

            e.printStackTrace();

            Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show();

        }

    }

    public void bt4_onClick(View v)

    {

        try {

        //1.获取输入流

            FileInputStream fis1 = openFileInput(FILENAME);

            //2.定义读取的数组

            byte[] bt11 = new byte[1024];

            //3.读出数据的长度

            int ii = 0;

            StringBuilder  bb1 = new StringBuilder ();

            while ((ii = fis1.read(bt11))>0)

            {

                bb1.append(new String(bt11,0, ii));

            }

            fis1.close();

            //设置显示读出的内容

            et4.setText(bb1);

            Toast.makeText(DataActivity1.this, "显示成功", Toast.LENGTH_SHORT).show();

        }

        catch (Exception e)

        {

            e.printStackTrace();

            Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show();

        }

    }

    //保存

    public void bt1_onClick(View v)

    {

        //1.获取Key和Value

        String key = et1.getText().toString();

        String value = et2.getText().toString();

        if (key.length() ==0||value.length() == 0)

        {

            Toast.makeText(DataActivity1.this, "key或value不能为空", Toast.LENGTH_SHORT).show();

        }

        else {

        //2.取得Editor        edit编辑器

        SharedPreferences.Editor editor = sp.edit();

        //3.放入键值对

        editor.putString(key,value);

        //4.提交保存

        boolean b = editor.commit();

        if (b)

        {

            Toast.makeText(DataActivity1.this, "保存成功", Toast.LENGTH_SHORT).show();

        }

        else

        {

            Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show();

        }

        }

    }

    //读取

    public void bt2_onClick(View v)

    {

        //1.获取要读的key

        String key = et1.getText().toString();

        //2.读并设置文本框

        et2.setText(sp.getString(key,"没有发现key"));

    }

}