Android中向SD卡读写数据，读SD卡和手机内存

package com.example.sdoperation;



import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.FileReader;



import android.support.v7.app.ActionBarActivity;

import android.support.v7.app.ActionBar;

import android.support.v4.app.Fragment;

import android.text.format.Formatter;

import android.os.Bundle;

import android.os.Environment;

import android.os.StatFs;

import android.util.StateSet;

import android.view.LayoutInflater;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.ViewGroup;

import android.widget.Button;

import android.widget.TextView;

import android.widget.Toast;

import android.os.Build;



public class MainActivity extends ActionBarActivity implements OnClickListener{

    

    private Button btnSaveSD;

    

    private Button btnReadSD;

    

    private Button btnGetSD;

    

    private Button btnGetPhone;

    

    private TextView tvMemory;

    



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        

        //获得组件

        btnGetSD = (Button) findViewById(R.id.btn_get);

        btnSaveSD = (Button)findViewById(R.id.btn_saveSD);

        tvMemory = (TextView) findViewById(R.id.tv_memoray);

        btnReadSD = (Button)findViewById(R.id.btn_readSD);

        btnGetPhone = (Button)findViewById(R.id.btn_readPhone);

        

        //添加点击事件

        btnGetSD.setOnClickListener(this);

        btnSaveSD.setOnClickListener(this);

        btnReadSD.setOnClickListener(this);

        btnGetPhone.setOnClickListener(this);

    }



    @Override

    public void onClick(View v) {

        switch (v.getId()) {

        case R.id.btn_saveSD:

            saveFile2Sd();

            break;

        case R.id.btn_readSD:

            readFile2Sd();

            break;

        case R.id.btn_get:

            getSDDetail();

            break;

        case R.id.btn_readPhone:

            getPhoneDetail();

            break;



        default:

            break;

        }

        

    }



    /**

     * 读手机内存

     */

    private void getPhoneDetail() {

        File path = Environment.getDataDirectory();

        StatFs stat = new StatFs(path.getPath());

        long blockSize = stat.getBlockSize();

        long blockCount = stat.getBlockCount();

        long avilableBlocks = stat.getAvailableBlocks();

        

        long totalSize = blockSize*blockCount;

        long avilableSize = blockSize*avilableBlocks;

        

        String totalSizeStr = Formatter.formatFileSize(this, totalSize);

        String alilableSizeStr = Formatter.formatFileSize(this, avilableSize);

        

        tvMemory.setText("总内存："+totalSizeStr + "可用内存：" +alilableSizeStr);

    }



    /**

     * 读SD卡内存

     */

    private void getSDDetail() {

        File path = Environment.getExternalStorageDirectory();

        StatFs stat = new StatFs(path.getPath());

        long blockSize = stat.getBlockSize();

        long blockCount = stat.getBlockCount();

        long avilableBlocks = stat.getAvailableBlocks();

        

        long totalSize = blockSize*blockCount;

        long avilableSize = blockSize*avilableBlocks;

        

        String totalSizeStr = Formatter.formatFileSize(this, totalSize);

        String alilableSizeStr = Formatter.formatFileSize(this, avilableSize);

        

        tvMemory.setText("总内存："+totalSizeStr + "可用内存：" +alilableSizeStr);

    }



    /**

     * 向SD卡写数据

     */

    private void saveFile2Sd()  {

        //获得SD卡的状态

        String sdState = Environment.getExternalStorageState();

        if (sdState.equals(Environment.MEDIA_MOUNTED)) {

            File file = new File(Environment.getExternalStorageDirectory(), "info.txt");

            FileOutputStream fos;

            try {

                fos = new FileOutputStream(file);

                fos.write("xxx".getBytes());

                fos.close();

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

            } catch (Exception e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }

        } else {

            Toast.makeText(this, "SD卡不存在", Toast.LENGTH_SHORT).show();

        }

    }

    

    /**

     * 从SD卡读数据

     */

    private void readFile2Sd()  {

        //获得SD卡的状态

        String sdState = Environment.getExternalStorageState();

        if (sdState.equals(Environment.MEDIA_MOUNTED)) {

            File file = new File(Environment.getExternalStorageDirectory(), "info.txt");

            BufferedReader br;

            try {

                br = new BufferedReader(new FileReader(file));

                String content = br.readLine();

                tvMemory.setText(content);

                br.close();

                Toast.makeText(this, "读取成功", Toast.LENGTH_SHORT).show();

            } catch (Exception e) {

                Toast.makeText(this, "SD卡不存在", Toast.LENGTH_SHORT).show();

            }

        } else {

            Toast.makeText(this, "SD卡不存在", Toast.LENGTH_SHORT).show();

        }

    }



}