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Android怎样捕获应用的crash信息
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我们的应用不可避免的会发生crash,假设是在调试阶段,我们能够使用Logcat查看异常信息。可是假设应用公布之后呢?假设在用户那边crash了,假设我们能够捕获这些crash信息,那么对我们定位crash原因并修复问题是非常有帮助的。
应用crash就可以能是Java层的异常导致的,也可能是native层导致,以下分别来看一下该怎样处理。
1 Java层的未捕获异常处理
先来看一下Java层的crash信息收集吧。要想捕获Java层的crash信息并不难。Android已经提供了接口来帮助我们监控系统的未捕获的异常:使用Thread.setDefaultUncaughtExceptionHandler就能够让我们轻松的监控应用的不论什么意外crash。
首先来看一下Thread.setDefaultUncaughtExceptionHandler这种方法:
/** * Sets the default uncaught exception handler. This handler is invoked in * case any Thread dies due to an unhandled exception. * * @param handler * The handler to set or null. */ public static void setDefaultUncaughtExceptionHandler(UncaughtExceptionHandler handler) { Thread.defaultUncaughtHandler = handler; }
从Thread.setDefaultUncaughtExceptionHandler这种方法的凝视就能够看到:当进程内(由于Thread.defaultUncaughtHandler 是一个静态变量,因此对整个进程内的全部线程有效)的不论什么线程发生未捕获异常时。会调用这里设置的handler。那我们看一下UncaughtExceptionHandler 这个类吧:
/** * Implemented by objects that want to handle cases where a thread is being * terminated by an uncaught exception. Upon such termination, the handler * is notified of the terminating thread and causal exception. If there is * no explicit handler set then the thread's group is the default handler. */ public static interface UncaughtExceptionHandler { /** * The thread is being terminated by an uncaught exception. Further * exceptions thrown in this method are prevent the remainder of the * method from executing, but are otherwise ignored. * * @param thread the thread that has an uncaught exception * @param ex the exception that was thrown */ void uncaughtException(Thread thread, Throwable ex); }
从源代码能够看出。UncaughtExceptionHandler 事实上是一个接口,它仅仅定义了一个方法uncaughtException(Thread thread, Throwable ex),当线程由于遇到未捕获异常而终止的时候就会调用这种方法。
假设我们想要捕获应用的crash信息,那么定义一个自己的UncaughtExceptionHandler 就能够,当然我们须要在自己的UncaughtExceptionHandler 里面把crash信息保存起来,必要的时候还能够上传到我们的server,这样就能够非常方便的收集用户的crash信息。
2 native层的异常处理
假设我们的应用使用到c/c++,那么也须要收集native层的异常处理。
大家都知道。Android的底层是基于Linux的,那么native层的未捕获异常就能够通过捕获信号来处理了。Native层假设异常终止会发出SIGKILL信号。我们能够使用sigaaction来注冊一个信号处理函数来处理SIGKILL信号,这样就能够收集到native层的未捕获异常了。
这里给出一个大概的代码框架:
void sigkill_handler(int signo){ //打印堆栈,并写入到文件里 } void install(){ struct sigaction act, oldact; act.sa_handler = sigkill_handler; sigaddset(&act.sa_mask, SIGKILL); sigaction(SIGKILL, &act, &oldact);//注冊信号处理函数 ...... }
3 实现
结合上面的介绍。以下就来定义一个自己的UncaughtExceptionHandler 。这个样例仅仅处理了Java层的crash收集,并把收集到的crash信息保存到sd卡上。这里给我们自己定义的crash处理器起了一个名字叫做AppCR(Application Crash Response)。
首先定义ErrorReporter ,它实现了UncaughtExceptionHandler :
public class ErrorReporter implements UncaughtExceptionHandler { private final Application mContext; private final ReporterExecutor mReporterExecutor; ErrorReporter(Application context, boolean enabled) { mContext = context; final Thread.UncaughtExceptionHandler defaultExceptionHandler = Thread .getDefaultUncaughtExceptionHandler(); mReporterExecutor = new ReporterExecutor(context, defaultExceptionHandler); mReporterExecutor.setEnabled(enabled); Thread.setDefaultUncaughtExceptionHandler(this); } @Override public void uncaughtException(final Thread thread,final Throwable ex) { // TODO Auto-generated method stub LogUtil.i(AppCR.LOG_TAG,"catch uncaughtException"); mReporterExecutor.execute(thread, ex); } public void setEnabled(boolean enabled) { LogUtil.i(AppCR.LOG_TAG, "AppCR is" + (enabled ?"enabled" : "disabled") + " for " + mContext.getPackageName()); } }
ReporterExecutor会调用Thread.setDefaultUncaughtExceptionHandler(this);来改动默认的UncaughtExceptionHandler。当发生未捕获的异常时。调用mReporterExecutor.execute(thread, ex);来处理异常。
ReporterExecutor 中把异常信息以及操作系统的相关信息保存到文件里。
public class ReporterExecutor { public static final String TAG = ReporterExecutor.class.getSimpleName(); private Context mContext; private boolean mEnabled = false; private final Thread.UncaughtExceptionHandler mDefaultExceptionHandler; private File mCrashInfoFile; public ReporterExecutor(Context context, Thread.UncaughtExceptionHandler defaultedExceptionHandler) { mContext = context; mDefaultExceptionHandler = defaultedExceptionHandler; if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) { File path = Environment.getExternalStorageDirectory(); File dir = new File(path, "BleFairy"); if (!dir.exists()) { dir.mkdirs(); } mCrashInfoFile = new File(dir, getCrashFileName()); if (!mCrashInfoFile.exists()) { try { mCrashInfoFile.createNewFile(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } } public boolean isEnabled() { return mEnabled; } public void setEnabled(boolean enabled) { mEnabled = enabled; } public void execute(Thread thread, Throwable ex) { if (!mEnabled) { endApplication(thread, ex); return; } // log crash info to file Log.w(AppCR.LOG_TAG, "getSysInfo."); CrashReportData data = http://www.mamicode.com/CrashReportData.produce(thread, ex, mContext);>CrashReportData 类用于保存异常信息:
public class CrashReportData { private final String info; private CrashReportData(String crashInfo) { this.info = crashInfo; } public static CrashReportData produce(Thread thread, Throwable ex, Context context) { ByteArrayOutputStream out = new ByteArrayOutputStream(); PrintStream print = new PrintStream(out); out.toString(); print.append("crahtime:" + TimeUtil.getCurTimeString()).append("\n"); print.append(SysInfo.getSysInfo(context)).append("\n"); print.append(thread.getName()).append("(threadID=" + thread.getId() + ")").append("\n"); print.append(ex.getMessage()).append("\n"); ex.printStackTrace(print); return new CrashReportData(out.toString()); } public void writeToFile(File file) { PrintWriter printer = null; try { // append to the end of crash file BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(file, true)); printer = new PrintWriter(out); printer.println(info); printer.flush(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { if (printer != null) { printer.close(); } LogUtil.w(AppCR.LOG_TAG, "write exception info to file over."); } } @Override public String toString() { // TODO Auto-generated method stub return info; // return super.toString(); } }SysIno类:
public class SysInfo { public static String getSysInfo(Context context) { StringBuilder info = new StringBuilder(); info.append("osVersion=Android ").append(Build.VERSION.RELEASE).append("\n"); info.append("model=").append(Build.MODEL).append("\n"); info.append("brand=").append(Build.BRAND).append("\n"); LogUtil.i(AppCR.LOG_TAG, "sys info collect over."); return info.toString(); } }使用AppCR来安装我们的crash处理器:
public class AppCR { public static final String LOG_TAG=AppCR.class.getSimpleName(); private static ErrorReporter mErrorReporter; public static void init(Application application){ init(application,true); } public static void init(Application application,boolean enabled){ mErrorReporter = new ErrorReporter(application, enabled); } }Application中安装上面自己定义的AppCR就能够了:
public class BeaconApplication extends Application { private final String TAG = "BeaconFairy.BeaconApplication"; @Override public void onCreate() { super.onCreate(); AppCR.init(this,true); } }须要注意的是:我们须要定义自己的Application,然后改动manifest就能够啦,还要记得加上写SD卡的权限:
<application android:name=".BeaconApplication" android:allowBackup="true" android:allowTaskReparenting="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > ........ </application>申请写SD卡的权限:<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />到此为止,我们自己定义的crash信息收集程序AppCR就完毕了。
Android怎样捕获应用的crash信息