Android编程实现捕获程序异常退出时的错误log信息功能详解

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
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.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
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 {
 private static final String TAG = CrashHandler.class.getSimpleName();
 private static final String SINGLE_RETURN = "\n";
 private static final String SINGLE_LINE = "--------------------------------";
 private static CrashHandler mCrashHandler;
 private Context mContext;
 private UncaughtExceptionHandler mDefaultHandler;
 private StringBuffer mErrorLogBuffer = new StringBuffer();
 /**
  * 获取CrashHandler实例，单例模式。
  *
  * @return 返回CrashHandler实例
  */
 public static CrashHandler getInstance() {
  if (mCrashHandler == null) {
   synchronized (CrashHandler.class) {
    if (mCrashHandler == null) {
     mCrashHandler = new CrashHandler();
    }
   }
  }
  return mCrashHandler;
 }
 public void init(Context context) {
  mContext = context;
  // 获取系统默认的uncaughtException处理类实例
  mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
  // 设置成我们处理uncaughtException的类
  Thread.setDefaultUncaughtExceptionHandler(this);
 }
 @Override
 public void uncaughtException(Thread thread, Throwable ex) {
  Log.d(TAG, "uncaughtException:" + ex);
  if (!handleException(ex) && mDefaultHandler != null) {
   // 如果用户没有处理异常就由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) {
    e.printStackTrace();
   }
   android.os.Process.killProcess(android.os.Process.myPid());
  }
 }
 //处理异常事件
 private boolean handleException(Throwable ex) {
  if (ex == null) {
   return false;
  }
  new Thread(new Runnable() {
   @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();
  // 收集设备参数信息
  collectDeviceInfo(mContext);
  // 收集错误日志
  collectCrashInfo(ex);
  // 保存错误日志
  saveErrorLog();
  //TODO: 这里可以加一个网络的请求，发送错误log给后台
//  sendErrorLog();
  return true;
 }
 //保存日志到/mnt/sdcard/AppLog/目录下，文件名已时间yyyy-MM-dd_hh-mm-ss.log的形式保存
 private void saveErrorLog() {
  if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
   SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh-mm-ss", Locale.getDefault());
   String format = sdf.format(new Date());
   format += ".log";
   String path = Environment.getExternalStorageDirectory().getPath()+"/AppLog/";
   File file = new File(path);
   if (!file.exists()){
    file.mkdirs();
   }
   FileOutputStream fos = null;
   try {
    fos = new FileOutputStream(path+format);
    fos.write(mErrorLogBuffer.toString().getBytes());
    fos.flush();
   } catch (FileNotFoundException e) {
    e.printStackTrace();
   } catch (IOException e) {
    e.printStackTrace();
   } finally {
    if (fos != null) {
     try {
      fos.close();
      fos = null;
     } catch (IOException e) {
      e.printStackTrace();
     }
    }
   }
  }
 }
 //收集错误信息
 private void collectCrashInfo(Throwable ex) {
  Writer info = new StringWriter();
  PrintWriter printWriter = new PrintWriter(info);
  ex.printStackTrace(printWriter);
  Throwable cause = ex.getCause();
  while (cause != null) {
   cause.printStackTrace(printWriter);
   cause = cause.getCause();
  }
  String result = info.toString();
  printWriter.close();
  //将错误信息加入mErrorLogBuffer中
  append("", result);
  mErrorLogBuffer.append(SINGLE_LINE + SINGLE_RETURN);
  Log.d(TAG, "saveCrashInfo2File:" + mErrorLogBuffer.toString());
 }
 //收集应用和设备信息
 private void collectDeviceInfo(Context context) {
  //每次使用前，清掉mErrorLogBuffer里的内容
  mErrorLogBuffer.setLength(0);
  mErrorLogBuffer.append(SINGLE_RETURN + SINGLE_LINE + SINGLE_RETURN);
  //获取应用的信息
  PackageManager pm = context.getPackageManager();
  try {
   PackageInfo pi = pm.getPackageInfo(context.getPackageName(),
     PackageManager.GET_ACTIVITIES);
   if (pi != null) {
    append("versionCode", pi.versionCode);
    append("versionName", pi.versionName);
    append("packageName", pi.packageName);
   }
  } catch (NameNotFoundException e) {
   e.printStackTrace();
  }
  mErrorLogBuffer.append(SINGLE_LINE + SINGLE_RETURN);
  //获取设备的信息
  Field[] fields = Build.class.getDeclaredFields();
  getDeviceInfoByReflection(fields);
  fields = Build.VERSION.class.getDeclaredFields();
  getDeviceInfoByReflection(fields);
  mErrorLogBuffer.append(SINGLE_LINE + SINGLE_RETURN);
 }
 //获取设备的信息通过反射方式
 private void getDeviceInfoByReflection(Field[] fields) {
  for (Field field : fields) {
   try {
    field.setAccessible(true);
    append(field.getName(), field.get(null));
   } catch (IllegalArgumentException e) {
    e.printStackTrace();
   } catch (IllegalAccessException e) {
    e.printStackTrace();
   }
  }
 }
 //mErrorLogBuffer添加友好的log信息
 private void append(String key, Object value) {
  mErrorLogBuffer.append("" + key + ":" + value + SINGLE_RETURN);
 }
}

import android.app.Application;
public class CrashApplication extends Application{
 @Override
 public void onCreate() {
  super.onCreate();
  CrashHandler.getInstance().init(this);
 }
}

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
  android:allowBackup="true"
  android:name=".CrashApplication"
  android:icon="@drawable/ic_launcher"
  android:label="@string/app_name"
  android:theme="@style/AppTheme" >
  <activity
   android:name="com.example.crashtestdemo.MainActivity"
   android:label="@string/app_name" >
   <intent-filter>
    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LAUNCHER" />
   </intent-filter>
  </activity>
</application>