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
<!-- 外存储写权限，构建语法需要用到此权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<!-- 外存储读权限，构建语法需要用到此权限 -->
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
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
// }
}
`
