安卓程序运行中突然崩溃的时候打印日志到本地

转载自：http://blog.sina.com.cn/s/blog_6a528c550102vc1a.html Yocn博客

我们在开发android应用的时候经常有这样一个情景：程序用着用着在某个地方崩溃了，每次的情况都不尽相同，这时候我们没有在电脑旁边，有电脑的时候去看代码的时候总是觉着哪儿都不可能出错。这时候我们就想如果我们能得到异常退出时候的log信息就好了。
这时候下面这一段代码就可能相当有用了：

package com.test.application;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
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;

import com.duole.fm.utils.Constants;

public class CrashHandler implements UncaughtExceptionHandler {

// 系统默认的UncaughtException处理类private Thread.UncaughtExceptionHandler mDefaultHandler;// CrashHandler实例private static CrashHandler instance;// 程序的Context对象private Context mContext;// 用来存储设备信息和异常信息private Map infos = new HashMap();// 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");private CrashHandler() {}public static CrashHandler getInstance() {    if (instance == null)        instance = new CrashHandler();    return instance;}public void init(Context context) {    mContext = context;    Log.e(Constants.TAG, "error : ");    // 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);}@Overridepublic 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(Constants.TAG, "error : ", e);        }        // 退出程序        android.os.Process.killProcess(android.os.Process.myPid());        System.exit(1);    }}private boolean handleException(Throwable ex) {    if (ex == null) {        return false;    }    // 收集设备参数信息    collectDeviceInfo(mContext);    // 使用Toast来显示异常信息    new Thread() {        @Override        public void run() {            Looper.prepare();            Toast.makeText(mContext, "很抱歉,程序出现异常,即将退出.", Toast.LENGTH_SHORT).show();            Looper.loop();        }    }.start();    // 保存日志文件    try {        saveCatchInfo2File(ex);    } catch (Exception e) {        e.printStackTrace();    }    return true;}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(Constants.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(Constants.TAG, field.getName() + " : " + field.get(null));        } catch (Exception e) {            Log.e(Constants.TAG, "an error occured when collect crash info", e);        }    }}private String saveCatchInfo2File(Throwable ex) {    StringBuffer sb = new StringBuffer();    for (Map.Entry 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();    sb.append(result);    try {        long timestamp = System.currentTimeMillis();        String time = formatter.format(new Date());        String fileName = "crash-" + time + "-" + timestamp + ".log";        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {            String path = Constants.SDPATH + "/crash/";            File dir = new File(path);            if (!dir.exists()) {                dir.mkdirs();            }            FileOutputStream fos = new FileOutputStream(path + fileName);            fos.write(sb.toString().getBytes());            // 发送给开发人员            sendCrashLog2PM(path + fileName);            fos.close();        }        return fileName;    } catch (Exception e) {        Log.e(Constants.TAG, "an error occured while writing file...", e);    }    return null;}private void sendCrashLog2PM(String fileName) {    if (!new File(fileName).exists()) {        Toast.makeText(mContext, "日志文件不存在！", Toast.LENGTH_SHORT).show();        return;    }    FileInputStream fis = null;    BufferedReader reader = null;    String s = null;    try {        fis = new FileInputStream(fileName);        reader = new BufferedReader(new InputStreamReader(fis, "GBK"));        while (true) {            s = reader.readLine();            if (s == null)                break;            // 由于目前尚未确定以何种方式发送，所以先打出log日志。            Log.i("info", s.toString());        }    } catch (FileNotFoundException e) {        e.printStackTrace();    } catch (IOException e) {        e.printStackTrace();    } finally { // 关闭流        try {            reader.close();            fis.close();        } catch (IOException e) {            e.printStackTrace();        }    }}

}

在Application里面加上下面这句：
CrashHandler catchHandler = CrashHandler.getInstance();
catchHandler.init(getApplicationContext());

这样就可以随时得到crash时候的log信息了