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();
}
}

}