1.Log2File工具类的作用

2.Log2File工具类源码

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Date;

import android.content.Context;
import android.os.Environment;

public class Log2File
{
    private static boolean  logInit;
    private static BufferedWriter writer;
    
    private Log2File()
    {
        
    }
    
    /**
     * 初始化Log,创建log文件
     * @param ctx
     * @param fileName
     * @return
     */
    public static boolean init(Context ctx, String fileName)
    {
        if(!logInit)
        {           
            String state = Environment.getExternalStorageState();
            if (Environment.MEDIA_MOUNTED.equals(state))
            {
                File sdDir = Environment.getExternalStorageDirectory();
                File logDir = new File(sdDir.getAbsolutePath() + "/log2file/" + 
                        ctx.getPackageName() + "/");
                
                try {
                    if(!logDir.exists())
                    {
                        logDir.mkdirs();
                    }
                    
                    File logFile = new File(logDir, fileName);
                    logFile.createNewFile();
                    
                    writer = new BufferedWriter(new FileWriter(logFile, true));
                    logInit = true;
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                
            }
            
        }
        
        return logInit;
    }
    
    /**
     * 写一条log
     * @param msg
     */
    public static void w(String msg)
    {
        if(logInit)
        {
            try {
                Date date = new Date();
                writer.write("[" + date.toLocaleString() + "] " + msg);
                writer.newLine();
                writer.flush();
            } catch (IOException e) {
                // TODO Auto-generated catch block
            }
        }
    }
    
    /**
     * 关闭log
     */
    public static void close()
    {
        if(logInit)
        {
            try {
                writer.close();
                writer = null;
                
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
            logInit = false;
        }
    }
}

3.Log2File工具类的使用

public static boolean init(Context ctx, String fileName)

2.调用w写入log

   public static void w(String msg)

    public static void close()

分享一个将Log记录到文件中的工具类

原文：http://blog.csdn.net/grackergao/article/details/18322749