为了读取到app运行时的日志，一般的作法是单独开一个线程，在app运行的启动线程，然后app退出时停掉线程。
然而我们更好的方法是开启一个service，然后在里面做日志记录，代码如下：
package com.hai.logcat;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.List;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningAppProcessInfo;
import android.app.Service;
import android.content.Intent;
import android.os.Environment;
import android.os.IBinder;
import android.os.Looper;
import android.util.Log;
import android.widget.Toast;
public class MyLogcat extends Service {
Thread thread;
boolean readlog = true;
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
Log.d("hhp", "onCreate");
thread = new Thread(new Runnable() {
@Override
public void run() {
log2();//个人觉得这个方法更实用
}
});
}
@Override
public void onStart(Intent intent, int startId) {
thread.start();
Log.d("hhp", "onStart");
super.onStart(intent, startId);
}
/**
* 方法1
*/
private void log2() {
Log.d("hhp", "log2 start");
String[] cmds = { "logcat", "-c" };
String shellCmd = "logcat -v time -s *:W "; // adb logcat -v time *:W
Process process = null;
Runtime runtime = Runtime.getRuntime();
BufferedReader reader = null;
try {
runtime.exec(cmds).waitFor();
process = runtime.exec(shellCmd);
reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) {
if (line.contains(String.valueOf(android.os.Process.myPid()))) {
// line = new String(line.getBytes("iso-8859-1"), "utf-8");
writeTofile(line);
}
}
} catch (Exception e) {
e.printStackTrace();
}
Log.d("hhp", "log2 finished");
}
/**
* 方法2
*/
private void log() {
Log.d("hhp", "log start");
String[] cmds = { "logcat", "-c" };
String shellCmd = "logcat -v time -s *:W ";// //adb logcat -v time *:W
Process process = null;
InputStream is = null;
DataInputStream dis = null;
String line = "";
Runtime runtime = Runtime.getRuntime();
try {
runtime.exec(cmds);
process = runtime.exec(shellCmd);
is = process.getInputStream();
dis = new DataInputStream(is);
// String filter = GetPid();
String filter = android.os.Process.myPid() + "";
while ((line = dis.readLine()) != null) { //这里如果输入流没断，会一直循环下去。
line = new String(line.getBytes("iso-8859-1"), "utf-8");
if (line.contains(filter)) {
int pos = line.indexOf(":");
Log.d("hhp2", line + "");
writeTofile(line);
}
}
} catch (Exception e) {
}
Log.d("hhp", "log finished");
}
private void writeTofile(String line) {
String content = line + "\r\n";
File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath()
+ "/logcat/myLog.txt");
if (!file.exists()) {
try {
file.createNewFile();
} catch (Exception e) {
e.printStackTrace();
}
}
FileOutputStream fos;
try {
fos = new FileOutputStream(file, true);
fos.write(content.getBytes());
fos.flush();
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void onDestroy() {
super.onDestroy();
stopSelf();
}
}
代码比较简单，所以没怎么注视了。说下大概思路：在service开启的时候，就开启线程不停地从logcat中读取输入流，
把读到的信息存入文件中，service停止的时候线程stop，就这么简单。
当然要读入系统日志还需要添加权限：
<uses-permission android:name="android.permission.READ_LOGS" />
下面是我记录的测试日志,信息记录的有点多，实际中可以运用正则过滤掉一些信息。
上面的代码基本可以记录本app运行中的日志，但如果中途有未捕获的异常导致app奔溃，那么这个未捕获的异常导致的奔溃上面代码就记录不到了。
因为这个异常导致app奔溃，虚拟机挂掉，那当然记录日志的线程也停了。那怎么捕获这类我们未捕获的异常（运行时异常）呢，幸好android这样
一个接口UncaughtExceptionHandler，当app奔溃前，它会先通知这个接口，这样我们就可以在app奔溃前做点自己想做的事了。
关于怎么捕获奔溃异常，我觉得这位哥们的一片博客写的不错http://blog.csdn.net/liuhe688/article/details/6584143#， 我借鉴着改了下：
package com.hai.logcat;
import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.lang.Thread.UncaughtExceptionHandler;
import java.lang.reflect.Field;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.Build;
import android.os.Environment;
import android.os.Looper;
import android.util.Log;
import android.widget.Toast;
public class CrashHandler implements UncaughtExceptionHandler {
public static final String TAG = "CrashHandler";
// 系统默认的UncaughtException处理类
private Thread.UncaughtExceptionHandler mDefaultHandler;
// CrashHandler实例
private static CrashHandler INSTANCE = new CrashHandler();
// 程序的Context对象
private Context mContext;
// 用来存储设备信息和异常信息
private Map<String, String> infos = new HashMap<String, String>();
// 用于格式化日期,作为日志文件名的一部分
private DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss ");
/** 保证只有一个CrashHandler实例 */
private CrashHandler() {
}
/** 获取CrashHandler实例 ,单例模式 */
public static CrashHandler getInstance() {
return INSTANCE;
}
/**
* 初始化
*
* @param context
*/
public void init(Context context) {
mContext = context;
// 获取系统默认的UncaughtException处理器
mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
// 设置该CrashHandler为程序的默认处理器
Thread.setDefaultUncaughtExceptionHandler(this);
}
/**
* 当UncaughtException发生时会转入该函数来处理
*/
@Override
public void uncaughtException(Thread thread, Throwable ex) {
if (!handleException(ex) && mDefaultHandler != null) {
// 如果用户没有处理则让系统默认的异常处理器来处理
mDefaultHandler.uncaughtException(thread, ex);
} else {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
Log.e(TAG, "error : ", e);
}
// 退出程序
android.os.Process.killProcess(android.os.Process.myPid());
System.exit(1);
}
}
/**
* 自定义错误处理,收集错误信息 发送错误报告等操作均在此完成.
*
* @param ex
* @return true:如果处理了该异常信息;否则返回false.
*/
private boolean handleException(final Throwable ex) {
if (ex == null) {
return false;
}
// 使用Toast来显示异常信息
new Thread() {
@Override
public void run() {
Looper.prepare();
ex.printStackTrace();
Toast.makeText(mContext, "很抱歉,程序出现异常,即将退出.", Toast.LENGTH_LONG).show();
Looper.loop();
}
}.start();
// 收集设备参数信息
collectDeviceInfo(mContext);
// 保存日志文件
saveCrashInfo2File(ex);
return true;
}
/**
* 收集设备参数信息
*
* @param ctx
*/
public void collectDeviceInfo(Context ctx) {
try {
PackageManager pm = ctx.getPackageManager();
PackageInfo pi = pm.getPackageInfo(ctx.getPackageName(), PackageManager.GET_ACTIVITIES);
if (pi != null) {
String versionName = pi.versionName == null ? "null" : pi.versionName;
String versionCode = pi.versionCode + "";
infos.put("versionName", versionName);
infos.put("versionCode", versionCode);
}
} catch (NameNotFoundException e) {
Log.e(TAG, "an error occured when collect package info", e);
}
Field[] fields = Build.class.getDeclaredFields();
for (Field field : fields) {
try {
field.setAccessible(true);
infos.put(field.getName(), field.get(null).toString());
Log.d(TAG, field.getName() + " : " + field.get(null));
} catch (Exception e) {
Log.e(TAG, "an error occured when collect crash info", e);
}
}
}
/**
* 保存错误信息到文件中
*
* @param ex
* @return 返回文件名称,便于将文件传送到服务器
*/
private String saveCrashInfo2File(Throwable ex) {
StringBuffer sb = new StringBuffer();
for (Map.Entry<String, String> entry : infos.entrySet()) {
String key = entry.getKey();
String value = entry.getValue();
sb.append(key + "=" + value + "\n");
}
Writer writer = new StringWriter();
PrintWriter printWriter = new PrintWriter(writer);
ex.printStackTrace(printWriter);
Throwable cause = ex.getCause();
while (cause != null) {
cause.printStackTrace(printWriter);
cause = cause.getCause();
}
printWriter.close();
String result = writer.toString();
String time = formatter.format(new Date());
sb.append(time + result);
try {
long timestamp = System.currentTimeMillis();
String fileName = "crash.log";
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
String path =Environment.getExternalStorageDirectory().getAbsolutePath()+ "/logcat/";
File dir = new File(path);
if (!dir.exists()) {
dir.mkdirs();
}
FileOutputStream fos = new FileOutputStream(path + fileName, true);
fos.write((sb.toString()).getBytes());
fos.close();
}
return fileName;
} catch (Exception e) {
Log.e(TAG, "an error occured while writing file...", e);
}
return null;
}
}然后我们在Application中这样引用即可
package com.hai;
import android.app.Application;
import com.hai.logcat.CrashHandler;
public class MyApplication extends Application {
CrashHandler handler = null;
@Override
public void onCreate() {
super.onCreate();
handler = CrashHandler.getInstance();
handler.init(getApplicationContext());
}
}
版权声明：本文为博主原创文章，未经博主允许不得转载。
android app记录运行日志 捕获奔溃异常 ，存储日志到文件
原文地址：http://blog.csdn.net/u014763302/article/details/47422023
