SDcard

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
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;

public class SDCardUtils {

    // 判断SDCard是否挂载
    public static boolean isSDCardMounted() {
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            return true;
        }
        return false;
    }

    // 获得SDCard的根目录 如/storage/sdcard/
    public static String getSDCardBaseDir() {
        if (isSDCardMounted()) {
            File dir = Environment.getExternalStorageDirectory();
            return dir.getAbsolutePath();
        }
        return null;
    }

    // 获得SD卡的全部空间大小(单位:M)
    public static long getSDCardSize() {
        if (isSDCardMounted()) {
            String dir = getSDCardBaseDir();
            StatFs statFs = new StatFs(dir); // StatFs是C语言引入过来的
            long blockCount = statFs.getBlockCountLong(); // 有多少块
            long blockSize = statFs.getBlockSizeLong(); // 每块有多大
            return blockCount * blockSize / 1024 / 1024;
        }
        return 0;
    }

    // 获取SDCard空闲空间的大小(单位:M) (有多少空间还没被占用的)
    public static long getSDCardFreeSize() {
        if (isSDCardMounted()) {
            String dir = getSDCardBaseDir();
            StatFs statFs = new StatFs(dir); // StatFs是C语言引入过来的
            long freeBlockCount = statFs.getFreeBlocksLong(); // 空闲的块
            long blockSize = statFs.getBlockSizeLong(); // 每块有多大
            return freeBlockCount * blockSize / 1024 / 1024;
        }
        return 0;
    }

    // 获取SDCard可用空间的大小(单位:M) (有多少空间你可以使用的)
    public static long getSDCardAvailSize() {
        if (isSDCardMounted()) {
            String dir = getSDCardBaseDir();
            StatFs statFs = new StatFs(dir); // StatFs是C语言引入过来的
            long availBlockCount = statFs.getAvailableBlocksLong(); // 可用的块
            long blockSize = statFs.getBlockSizeLong(); // 每块有多大
            return availBlockCount * blockSize / 1024 / 1024;
        }
        return 0;
    }

    // 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) /storage/sdcard/{type}
    public static boolean saveData2SDCardPublicDir(byte[] data, String type, String filename) {
        if (isSDCardMounted()) {
            // 文件名:/storage/sdcard/Musics/111.txt
            // 文件名:getSDCardBaseDir()/{type}/{filename}
            String baseDir = getSDCardBaseDir();
            String file = baseDir + File.separator + type + "/" + filename;
            try {
                OutputStream os = new FileOutputStream(file);
                os.write(data);
                os.close();
                return true;
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return false;
    }

    // 往SDCard的自定义目录中保存数据 /storage/sdcard/{dir}
    public static boolean saveData2SDCardCustomDir(byte[] data, String dir, String filename) {
        if (isSDCardMounted()) {
            // /storage/sdcard/{dir}
            // getSDCardBaseDir()/{dir}/{filename}
            String baseDir = getSDCardBaseDir(); // SDCard目录
            String path = baseDir + "/" + dir; // SDCard中自定义的目录
            // 如果path不存在的话 需要创建目录
            File customPath = new File(path);
            if (!customPath.exists()) {
                customPath.mkdir();
            }
            String file = path + "/" + filename; // SDCard中自定义目录中的文件
            try {
                OutputStream os = new FileOutputStream(file);
                os.write(data);
                os.close();
                return true;
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
        return false;
    }

    // ：往SDCard的私有File目录下保存文件
    // /storage/sdcard/Android/data/包名/files/{type}/{filename}
    public static boolean saveData2SDCardPrivateFileDir(byte[] data, String type, String filename, Context context) {
        if (isSDCardMounted()) {
            // storage/sdcard/Android/data/包名/files/{type}/{filename}
            File path = context.getExternalFilesDir(type);
            if (!path.exists()) {
                path.mkdir();
            }
            String file = path.getAbsolutePath() + "/" + filename; // 文件路径
            try {
                OutputStream os = new FileOutputStream(file);
                os.write(data);
                os.close();
                return true;
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return false;
    }

    // 往SDCard的私有Cache目录下保存文件 /storage/sdcard/Android/data/包名/cache/{filename}
    public static boolean saveData2SDCardPrivateCacheDir(byte[] data, String filename, Context context) {
        if (isSDCardMounted()) {
            // storage/sdcard/Android/data/包名/cache/{filename}
            File path = context.getExternalCacheDir();
            if (!path.exists()) {
                path.mkdir();
            }
            String file = path.getAbsolutePath() + "/" + filename;
            try {
                OutputStream os = new FileOutputStream(file);
                os.write(data);
                os.close();
                return true;
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return false;
    }

    // 往SDCard的私有Cache目录下保存图像 /storage/sdcard/Android/data/包名/cache/{filename}  xxx.png xxx.jpg
    public static boolean saveBitmap2SDCardPrivateCacheDir(Bitmap bitmap, 
            String filename, Context context) {
        if(isSDCardMounted()) {
            // 路径/storage/sdcard/Android/data/包名/cache/{filename}
            File path = context.getExternalCacheDir();
            if(!path.exists()) {
                path.mkdir();
            }
            String file = path.getAbsolutePath() + "/" + filename; // bmp、jpg
            try {
                OutputStream os = new FileOutputStream(file);
                // 图片转换成byte[] 下面的代码代替os.write(...);
                // 判断到底是哪种图片的格式(jpg、png)
                if(filename.endsWith(".jpg") || filename.endsWith(".JPG")) {
                    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 (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
        return false;
    }
    
    // 从SDCard读取指定文件 /storage/sdcard/{filePath}
    public static byte[] loadFileFromSDCard(String filePath) {
        if(isSDCardMounted()) {
            // /storage/sdcard/{filePath}
            // getSDCardBaseDir()/{filePath}
            String path = getSDCardBaseDir();
            String file = path + "/" + filePath;
            try {
                InputStream is = new FileInputStream(file);
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                byte[] buffer = new byte[1024];
                int ret;
                while(true) {
                    ret = is.read(buffer);
                    if(ret < 0) {
                        break;
                    }
                    baos.write(buffer, 0, ret);
                }
                return baos.toByteArray(); // 返回字节数组
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return null;
    }

    // 从SDCard读取Bitmap并返回 /storage/sdcard/{filePath}
    public static Bitmap loadBitmapFromSDCard(String filePath) {
        if(isSDCardMounted()) {
            // 由于传入的参数已经是全路径了 因此不需要加上getSDCardBaseDir()
            try {
                InputStream is = new FileInputStream(filePath);
                byte[] buffer = new byte[1024];
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                int ret;
                while(true) {
                    ret = is.read(buffer);
                    if(ret < 0) {
                        break;
                    }
                    baos.write(buffer, 0, ret);
                }
                byte[] data = baos.toByteArray();
                return BitmapFactory.decodeByteArray(data, 0, data.length);
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return null;
    }
}