基本思路

当crash发生时，系统会调用UncaughtExceptionHandler的uncaughtException方法，我们能够在这种方法中捕获异常信息，把异常信息存到SD卡中。在合适的时候通过网络把crash信息传回server，这样就能够分析crash原因，在兴许的版本号中解决。
先看一下Thread类中的一个方法，setDefaultUncaughtExceptionHandler

public static void setDefaultUncaughtExceptionHandler(UncaughtExceptionHandler handler) {
    Thread.defaultUncaughtHandler = handler;
}

defaultUncaughtHandler是Thread类的静态成员变量。所以假设我们将自己定义的UncaughtExceptionHandler设置给Thread的话，那么当前进程内的全部线程都能使用这个UncaughtExceptionHandler来处理异常了。

CrashHandler

public class CrashHandler implements UncaughtExceptionHandler {
    private static final String TAG = "CrashHandler";
    private static final boolean DEBUG = true;

    private static final String PATH = Environment.getExternalStorageDirectory().getPath() + "/CrashTest/log/";
    private static final String FILE_NAME = "crash";
    private static final String FILE_NAME_SUFFIX = ".trace";

    private static CrashHandler sInstance = new CrashHandler();
    private UncaughtExceptionHandler mDefaultCrashHandler;
    private Context mContext;

    private CrashHandler() {
    }

    public static CrashHandler getInstance() {
        return sInstance;
    }

    //须要初始化的单例
    public void init(Context context) {
        mDefaultCrashHandler = Thread.getDefaultUncaughtExceptionHandler();
        Thread.setDefaultUncaughtExceptionHandler(this);
        mContext = context.getApplicationContext();
    }

    /**
     * 这个是最关键的函数。当程序中有未被捕获的异常，系统将会自己主动调用#uncaughtException方法
     * thread为出现未捕获异常的线程，ex为未捕获的异常，有了这个ex，我们就能够得到异常信息。
     */
    @Override
    public void uncaughtException(Thread thread, Throwable ex) {
        try {
            //导出异常信息到SD卡中
            dumpExceptionToSDCard(ex);
            uploadExceptionToServer();
            //这里能够通过网络上传异常信息到server。便于开发者分析日志从而解决bug
        } catch (IOException e) {
            e.printStackTrace();
        }

        ex.printStackTrace();

        //假设系统提供了默认的异常处理器。则交给系统去结束我们的程序，否则就由我们自己结束自己
        if (mDefaultCrashHandler != null) {
            mDefaultCrashHandler.uncaughtException(thread, ex);
        } else {
            Process.killProcess(Process.myPid());
        }

    }

    private void dumpExceptionToSDCard(Throwable ex) throws IOException {
        //假设SD卡不存在或无法使用。则无法把异常信息写入SD卡
        if (!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            if (DEBUG) {
                Log.w(TAG, "sdcard unmounted,skip dump exception");
                return;
            }
        }

        File dir = new File(PATH);
        if (!dir.exists()) {
            dir.mkdirs();
        }
        long current = System.currentTimeMillis();
        String time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date(current));
        File file = new File(PATH + FILE_NAME + time + FILE_NAME_SUFFIX);

        try {
            PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(file)));
            pw.println(time);
            dumpPhoneInfo(pw);
            pw.println();
            ex.printStackTrace(pw);
            pw.close();
        } catch (Exception e) {
            Log.e(TAG, "dump crash info failed");
        }
    }

    private void dumpPhoneInfo(PrintWriter pw) throws NameNotFoundException {
        PackageManager pm = mContext.getPackageManager();
        PackageInfo pi = pm.getPackageInfo(mContext.getPackageName(), PackageManager.GET_ACTIVITIES);
        pw.print("App Version: ");
        pw.print(pi.versionName);
        pw.print('_');
        pw.println(pi.versionCode);

        //android版本号号
        pw.print("OS Version: ");
        pw.print(Build.VERSION.RELEASE);
        pw.print("_");
        pw.println(Build.VERSION.SDK_INT);

        //手机制造商
        pw.print("Vendor: ");
        pw.println(Build.MANUFACTURER);

        //手机型号
        pw.print("Model: ");
        pw.println(Build.MODEL);

        //cpu架构
        pw.print("CPU ABI: ");
        pw.println(Build.CPU_ABI);
    }

    private void uploadExceptionToServer() {
      //TODO Upload Exception Message To Your Web Server
    }

}

用法

在Application的onCreate方法中配置一下就能够

public class TestApp extends Application {

    private static TestApp sInstance;

    @Override
    public void onCreate() {
        super.onCreate();
        sInstance = this;

        //在这里为应用设置异常处理程序，然后我们的程序才干捕获未处理的异常
        CrashHandler crashHandler = CrashHandler.getInstance();
        crashHandler.init(this);
    }

    public static TestApp getInstance() {
        return sInstance;
    }

}

原文在sparkyuan.me上，转载注明出处：http://sparkyuan.github.io/2016/03/28/使用UncaughtExceptionHandler来处理未捕获的异常/