android Loger日志类（获取内置sd卡）

 public static String getExternalSdCardPath() {

        if (SDCardUtils.isSDCardEnable()) {
            File sdCardFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath());
            return sdCardFile.getAbsolutePath();
        }

        String path = null;

        File sdCardFile = null;

        ArrayList<String> devMountList = getDevMountList();

        for (String devMount : devMountList) {
            File file = new File(devMount);

            if (file.isDirectory() && file.canWrite()) {
                path = file.getAbsolutePath();

                String timeStamp = new SimpleDateFormat("ddMMyyyy_HHmmss").format(new Date());
                File testWritable = new File(path, "test_" + timeStamp);

                if (testWritable.mkdirs()) {
                    testWritable.delete();
                } else {
                    path = null;
                }
            }
        }

        if (path != null) {
            sdCardFile = new File(path);
            return sdCardFile.getAbsolutePath();
        }

        return null;
    }

//读文件
    public static String readFile(String fileName) {

        try {
            File file = new File(fileName);

            FileInputStream fis = new FileInputStream(file);

            int length = fis.available();

            byte [] buffer = new byte[length];
            fis.read(buffer);

            String res = EncodingUtils.getString(buffer, "UTF-8");

            fis.close();
            return res;
        }
        catch (Exception ex)
        {
            ex.printStackTrace();
            return  null;
        }

    }


    private static ArrayList<String> getDevMountList() {
        String[] toSearch = readFile("/etc/vold.fstab").split(" ");
        ArrayList<String> out = new ArrayList<String>();
        for (int i = 0; i < toSearch.length; i++) {
            if (toSearch[i].contains("dev_mount")) {
                if (new File(toSearch[i + 2]).exists()) {
                    out.add(toSearch[i + 2]);
                }
            }
        }
        return out;
    }

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.text.SimpleDateFormat;
import java.util.Date;
import android.os.Environment;

/**
 * 日志打印类，提供了一个开关来决定是否打印日志
 */
public class Logger
{
    private final static SimpleDateFormat DATEFORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    private static final SimpleDateFormat PATHFORMATE =new SimpleDateFormat("yyyyMMdd");
    private static final SimpleDateFormat PATHFORMATE1 = new SimpleDateFormat("HH");
    private static boolean IsRecord=true;//是否记录日志

    //存储卡目录和手机内部目录
    private static final String ExternalStorePath = FileUtil.getExternalSdCardPath()+"nanbeiyoulog"
            +File.separator+PATHFORMATE.format(new Date())+File.separator;
    private static final String FileName = PATHFORMATE1.format(new Date())+".txt";

    public static void d(String tag,String msg)
    {
        if(IsRecord)
        {
            try {
                SaveToSD(tag,msg);
            }
            catch (Exception ex)
            {
                ex.printStackTrace();
            }
        }
    }

    private static void SaveToSD(String tag,String msg)
    {
        try{
            File path = new File(ExternalStorePath);
            if(!path.exists())
            {
                path.mkdirs();
            }
            File mLogFile = new File(ExternalStorePath+FileName);
            if(!mLogFile.exists())
            {
                mLogFile.createNewFile();
            }

            StringBuffer sb = new StringBuffer();
            sb.append(DATEFORMAT.format(new Date()));
            sb.append(": ");
            sb.append("DEBUG");
            sb.append(": ");
            sb.append(tag);
            sb.append(": ");
            sb.append(msg);
            sb.append("\n");
            RandomAccessFile raf = null;
            try
            {
                raf = new RandomAccessFile(mLogFile, "rw");
                raf.seek(mLogFile.length());
                raf.write(sb.toString().getBytes("UTF-8"));
            }
            catch (UnsupportedEncodingException e)
            {
                e.printStackTrace();

            }
            catch (IOException e)
            {
                e.printStackTrace();

            }
            finally
            {
                if(raf != null)
                {
                    try
                    {
                        raf.close();
                    }
                    catch (IOException e)
                    {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }

            }
        }
        catch (IOException ioe)
        {
            ioe.printStackTrace();
        }
    }

}