安卓笔记之SDCardUtils

package com.example.day0330_sdcard;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Environment;
import android.os.StatFs;
import android.util.Log;

public class SDCardUtils {
//判断SD卡是否挂载
public static boolean isSDCardMounted(){
//获取SD卡外部存储状态
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
return true;
}

return false;
}
//获取SD卡的根目录
public static String getSDCardBaseDir(){
if (isSDCardMounted()) {
File dir = Environment.getExternalStorageDirectory();
return dir.getAbsolutePath();
}
return null;
}
//获取SD卡全部内存空间大小
public static long getSDCardSize(){
if (isSDCardMounted()) {
String dir = getSDCardBaseDir();
//StatFs是从C语言引过来的
StatFs statFs = new StatFs(dir);
long blockCount = statFs.getBlockCountLong();//有多少块
long blockSize = statFs.getBlockSizeLong();//每块有多大
return blockCount*blockSize/1024/1024; //总大小
}
return 0;
}
//获取SD卡空闲空间大小(有多少空间还没被占用)
public static long getSDCardFreeSize(){
if (isSDCardMounted()) {
String dir = getSDCardBaseDir();
//StatFs是从C语言引过来的
StatFs statFs = new StatFs(dir);
long freeBlockCount = statFs.getFreeBlocksLong();//有多少块
long blockSize = statFs.getBlockSizeLong();//每块有多大
return freeBlockCount*blockSize/1024/1024; //总大小
}
return 0;
}
//获取SD卡可用剩余空间大小(还剩下多少空间)
public static long getSDCardAvailableSize(){
if (isSDCardMounted()) {
String dir = getSDCardBaseDir();
//StatFs是从C语言引过来的
StatFs statFs = new StatFs(dir);
long availableBlockCount = statFs.getAvailableBlocksLong();//有多少块
long blockSize = statFs.getBlockSizeLong();//每块有多大
return availableBlockCount*blockSize/1024/1024; //总大小
}
return 0;
}
//往SD卡九大目录保存文件
public static boolean saveData2SDCardpublicDir(byte[] bys,String type,String filename){
if (isSDCardMounted()) {
//获取SD卡的根目录
String baseDir = getSDCardBaseDir();
//获取文件的路径
String file = baseDir+File.separator+type+File.separator+filename;
try {
OutputStream os = new FileOutputStream(file);
os.write(bys);
os.close();
return true;
} catch (Exception e){
e.printStackTrace();
}
}
return false;
}
//往SDCard公有目录下保存文件 (九大公有目录中的一个，具体由type指定)
public static boolean saveData2SDCardCustomDir(byte[] bys,String dir,String filename){
if (isSDCardMounted()) {
//获取SD卡的根目录
String baseDir = getSDCardBaseDir();
String path =baseDir+File.separator+dir;
//获取自建文件夹的路径
File file1 = new File(path);
//判断文件夹是否存在，不存在的话就得先创建
if (!file1.exists()) {
file1.mkdir();
}
//获取文件的路径
String file = baseDir+File.separator+dir+File.separator+filename;
try {
OutputStream os = new FileOutputStream(file);
os.write(bys);
os.close();
return true;
} catch (Exception e) {
e.printStackTrace();
}
}
return false;
}
//往SDCard的私有File目录下保存文件
public static boolean saveData2SDCardPrivateFileDir(byte[] data, String type, String filename, Context context){
if (isSDCardMounted()) {
File path = context.getExternalFilesDir(type);
if (!path.exists()) {
path.mkdir();
}
String file = path.getAbsolutePath()+File.separator+filename;
try {
OutputStream os = new FileOutputStream(file);
os.write(data);
os.close();
return true;
} catch (Exception e) {
e.printStackTrace();
}
}
return false;
}
//往SDCard的私有Cache目录下保存文件
public static boolean saveData2SDCardPrivateCacheDir(byte[] data, String filename, Context context){
if (isSDCardMounted()) {
File path = context.getExternalCacheDir();
if (!path.exists()) {
path.mkdir();
}
String file = path.getAbsolutePath()+File.separator+filename;
try {
OutputStream os = new FileOutputStream(file);
os.write(data);
os.close();
return true;
} catch (Exception e) {
e.printStackTrace();
}
}
return false;
}
//往SDCard的私有Cache目录下保存图像

public static boolean saveBitmap2SDCardPrivateCacheDir(Bitmap bitmap, String filename, Context context){
if (isSDCardMounted()) {
File path = context.getExternalCacheDir();
if (!path.exists()) {
path.mkdir();
}
String file = path.getAbsolutePath()+File.separator+filename;
try {
OutputStream os = new FileOutputStream(file);
//把图片转成byte[]
//os.write();
//判断图片格式
if(filename.endsWith(".JPG")||filename.endsWith(".jap")){
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, os);
}else if(filename.endsWith(".PNG")||filename.endsWith(".png")){
bitmap.compress(Bitmap.CompressFormat.PNG, 100, os);
}
os.close();
return true;
} catch (Exception e) {
e.printStackTrace();
}
}
return false;
}
//从SDCard读取指定文件
public static byte[] loadFileFromSDCard(String filePath){
if (isSDCardMounted()) {
String path = getSDCardBaseDir();
String file = path+File.separator+filePath;
try {
InputStream is = new FileInputStream(file);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] bys = new byte[1024];
int len = 0;
while((len=is.read(bys))!=-1){
baos.write(bys, 0, len);
}
return baos.toByteArray();
} catch (Exception e) {
e.printStackTrace();
}
}
return null;
}
//从SDCard读取Bitmap并返回
public static Bitmap loadBitmapFromSDCard(String filePath){
if (isSDCardMounted()) {
//filePath就是全路径
try {
InputStream is = new FileInputStream(filePath);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] bys = new byte[1024];
int len = 0;
while((len=is.read(bys))!=-1){
baos.write(bys, 0, len);
}
byte[] data = baos.toByteArray();
Bitmap bitmap =BitmapFactory.decodeByteArray(data, 0, data.length);
return bitmap;
} catch (Exception e) {
e.printStackTrace();
}
}
return null;
}
//获取SD卡公有目录路径
public static String getSDCardPublicDir(String type){
if (isSDCardMounted()) {
File dir = Environment.getExternalStoragePublicDirectory(type);
return dir.getAbsolutePath();
}
return null;
}
//获取SDCard私有Cache目录路径
public static String getSDCardPrivateCacheDir(Context context){
if (isSDCardMounted()) {
File dir = context.getExternalCacheDir();
return dir.getAbsolutePath();
}
return null;
}
//获取SDCard私有File目录路径
public static String getSDCardPrivateFilesDir(Context context, String type){

if (isSDCardMounted()) {
File dir =context.getExternalFilesDir(type);
return dir.getAbsolutePath();
}

return null;
}
//判断一个文件是否存在
public static boolean isFileExists(String filePath){
if (isSDCardMounted()) {
File file = new File(filePath);
return file.exists();
}
return false;
}
//删除一个文件
public static boolean removeFileFromSDCard(String filePath){
if (isSDCardMounted()) {
File file =new File(filePath);
return file.delete();
}
return false;
}
}