Android 对程序异常崩溃的捕捉

 以下为异常捕捉处理代码：

 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;

 /**
  * UncaughtException处理类,当程序发生Uncaught异常的时候,有该类来接管程序,并记录发送错误报告.
  *
  *  需要在Application中注册，为了要在程序启动器就监控整个程序。
  */
 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;
    //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");

     /** 保证只有一个CrashHandler实例 */
     private CrashHandler() {}

     /** 获取CrashHandler实例 ,单例模式 */
     public static CrashHandler getInstance() {
         if(instance == null)
             instance = new CrashHandler();
         return instance;
     }

     /**
      * 初始化
      */
     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(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
         saveCatchInfo2File(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 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 = "/mnt/sdcard/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(TAG, "an error occured while writing file...", e);
         }
         return null;
     }

     /**
      * 将捕获的导致崩溃的错误信息发送给开发人员
      *
      * 目前只将log日志保存在sdcard 和输出到LogCat中，并未发送给后台。
      */
     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();
             }
         }
     }
 }

针对异常的捕捉要进行全局监控整个项目，所以要将其在Application中注册(也就是初始化)：

 import android.app.Application;

 public class CrashApplication extends Application {

     @Override
     public void onCreate() {
         super.onCreate();
         CrashHandler catchHandler = CrashHandler.getInstance();
         catchHandler.init(getApplicationContext());
     }
 }

现在模拟一个空指针异常：

 import android.app.Activity;
 import android.os.Bundle;

 public class CatchExceptionLogActivity extends Activity {
     /** Called when the activity is first created. */
     private String s;
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         System.out.println(s.equals("hello"));  // s没有进行赋值，所以会出现NullPointException异常
     }
 }

别忘了在配置文件中对Application进行注册：

 xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.forms.catchlog"
     android:versionCode="1"
     android:versionName="1.0" >

     <uses-sdk android:minSdkVersion="8" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>


     <application
         android:icon="@drawable/ic_launcher"
         android:label="@string/app_name"
         <span style="color:#ff0000;">android:name=".CrashApplication">span>
         <activity
             android:label="@string/app_name"
             android:name=".CatchExceptionLogActivity" >
             <intent-filter >
                 <action android:name="android.intent.action.MAIN" />

                 <category android:name="android.intent.category.LAUNCHER" />
             intent-filter>
         activity>
     application>

 manifest>