android 日记log保存到本地简单方法

安卓日常开发中，经常需要打印日记，经常需要把log输入到本地查看，本demo是把日记输出到本地的简单示例：

1.初始化保存路径（实例中为SD卡下： /storage/emulated/0/interprenter）

 /**
 * 初始化目录
 */
private void init(Context context) {
    if (Environment.getExternalStorageState().equals(
            Environment.MEDIA_MOUNTED)) {// 优先保存到SD卡中
        PATH_LOGCAT = Environment.getExternalStorageDirectory()
                .getAbsolutePath() + File.separator + "interprenter";
    } else {// 如果SD卡不存在，就保存到本应用的目录下
        PATH_LOGCAT = context.getFilesDir().getAbsolutePath()
                + File.separator + "interprenter";
    }
    File file = new File(PATH_LOGCAT);
    if (!file.exists()) {
        file.mkdirs();
        LogUtils.e("创建文件夹");
    }
    LogUtils.e(PATH_LOGCAT);
}

2.编写一个线程，用户收集和写入日记

private class LogDumper extends Thread {

    private Process logcatProc;
    private BufferedReader mReader = null;
    private boolean mRunning = true;
    String cmds = null;
    private String mPID;
    private FileOutputStream out = null;

    public LogDumper(String pid, String dir) {
        mPID = pid;
        try {
            out = new FileOutputStream(new File(dir, "log_"
                    + getFileName() + ".log"));

        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        /**
         *
         * 日志等级：*:v , *:d , *:w , *:e , *:f , *:s
         *
         * 显示当前mPID程序的 E和W等级的日志.
         *
         * */

        // cmds = "logcat *:e *:w | grep \"(" + mPID + ")\"";
        // cmds = "logcat  | grep \"(" + mPID + ")\"";//打印所有日志信息
        // cmds = "logcat -s way";//打印标签过滤信息
        cmds = "logcat *:e *:i | grep \"(" + mPID + ")\"";

    }

    public void stopLogs() {
        mRunning = false;
    }

    @Override
    public void run() {
        try {
            logcatProc = Runtime.getRuntime().exec(cmds);
            mReader = new BufferedReader(new InputStreamReader(
                    logcatProc.getInputStream()), 1024);
            String line = null;
            while (mRunning && (line = mReader.readLine()) != null) {
                if (!mRunning) {
                    break;
                }
                if (line.length() == 0) {
                    continue;
                }
                if (out != null && line.contains(mPID)) {
                    out.write((line + "\n").getBytes());
                }
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (logcatProc != null) {
                logcatProc.destroy();
                logcatProc = null;
            }
            if (mReader != null) {
                try {
                    mReader.close();
                    mReader = null;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                out = null;
            }

        }

    }

}

3.对线程控制，已便达到控制日记的收集情况

    public void start() {
    if (mLogDumper == null)
        mLogDumper = new LogDumper(String.valueOf(mPId), PATH_LOGCAT);
    mLogDumper.start();
}

public void stop() {
    if (mLogDumper != null) {
        mLogDumper.stopLogs();
        mLogDumper = null;
    }
}

4.使用初始化，最好在application中使用

   LogcatHelper.getInstance(this).start();

5.不要忘记添加读写权限

6.启动设备，运行一段时间后，shell命令进入到文件保存路径下查看log文件

命令：adb shell
	cd /storage/emulated/0/interprenter
	ls

7.adb命令pull出文件到本地

命令：exit 推出shell模式
	 adb pull /storage/emulated/0/interprenter/log_2018-11-26.log D:\interprenter
便可导出文件

8.完整代码

`package com.cniaomu.interprenter.util;

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

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.SimpleDateFormat;
import java.util.Date;

/**

---

• 修改日期 修改人 任务名称 功能或Bug描述
• 2018/8/16 20:46 MUZI102

---

*/
public class LogcatHelper {
private static LogcatHelper INSTANCE = null;
private static String PATH_LOGCAT;
private LogDumper mLogDumper = null;
private int mPId;

/**
 * 初始化目录
 */
private void init(Context context) {
    if (Environment.getExternalStorageState().equals(
            Environment.MEDIA_MOUNTED)) {// 优先保存到SD卡中
        PATH_LOGCAT = Environment.getExternalStorageDirectory()
                .getAbsolutePath() + File.separator + "interprenter";
    } else {// 如果SD卡不存在，就保存到本应用的目录下
        PATH_LOGCAT = context.getFilesDir().getAbsolutePath()
                + File.separator + "interprenter";
    }
    File file = new File(PATH_LOGCAT);
    if (!file.exists()) {
        file.mkdirs();
        LogUtils.e("创建文件夹");
    }
    LogUtils.e(PATH_LOGCAT);
}

public static LogcatHelper getInstance(Context context) {
    if (INSTANCE == null) {
        INSTANCE = new LogcatHelper(context);
    }
    return INSTANCE;
}

private LogcatHelper(Context context) {
    init(context);
    mPId = android.os.Process.myPid();
}

public void start() {
    if (mLogDumper == null)
        mLogDumper = new LogDumper(String.valueOf(mPId), PATH_LOGCAT);
    mLogDumper.start();
}

public void stop() {
    if (mLogDumper != null) {
        mLogDumper.stopLogs();
        mLogDumper = null;
    }
}

private class LogDumper extends Thread {

    private Process logcatProc;
    private BufferedReader mReader = null;
    private boolean mRunning = true;
    String cmds = null;
    private String mPID;
    private FileOutputStream out = null;

    public LogDumper(String pid, String dir) {
        mPID = pid;
        try {
            out = new FileOutputStream(new File(dir, "log_"
                    + getFileName() + ".log"));

        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        /**
         *
         * 日志等级：*:v , *:d , *:w , *:e , *:f , *:s
         *
         * 显示当前mPID程序的 E和W等级的日志.
         *
         * */

        // cmds = "logcat *:e *:w | grep \"(" + mPID + ")\"";
        // cmds = "logcat  | grep \"(" + mPID + ")\"";//打印所有日志信息
        // cmds = "logcat -s way";//打印标签过滤信息
        cmds = "logcat *:e *:i | grep \"(" + mPID + ")\"";

    }

    public void stopLogs() {
        mRunning = false;
    }

    @Override
    public void run() {
        try {
            logcatProc = Runtime.getRuntime().exec(cmds);
            mReader = new BufferedReader(new InputStreamReader(
                    logcatProc.getInputStream()), 1024);
            String line = null;
            while (mRunning && (line = mReader.readLine()) != null) {
                if (!mRunning) {
                    break;
                }
                if (line.length() == 0) {
                    continue;
                }
                if (out != null && line.contains(mPID)) {
                    out.write((line + "\n").getBytes());
                }
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (logcatProc != null) {
                logcatProc.destroy();
                logcatProc = null;
            }
            if (mReader != null) {
                try {
                    mReader.close();
                    mReader = null;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                out = null;
            }

        }

    }

}

public String getFileName() {
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    String date = format.format(new Date(System.currentTimeMillis()));
    return date;// 2012年10月03日 23:41:31
}

// public String getDateEN() {
// SimpleDateFormat format1 = new SimpleDateFormat(“yyyy-MM-dd HH:mm:ss”);
// String date1 = format1.format(new Date(System.currentTimeMillis()));
// return date1;// 2012-10-03 23:41:31
// }
}
`