Android之UncaughtExceptionHandler异常捕获

概要

在Android开发中，目前没有工业级的bug收集工具，不比java后台服务有各式各样的收集工具，Android用的更多一些
第三方的如bugly或者友盟等。那如何自己去收集呢？其实安卓原生提供了异常收集类UncaughtExceptionHandler。

UncaughtExceptionHandler正如其名称所示，用于收集未捕获的异常（简单的理解可以认为是崩溃异常）。
具体使用分为两步：

实现自定义的异常处理类：

public class CrashHandler implements Thread.UncaughtExceptionHandler {
    @Override
    public void uncaughtException(Thread thread, Throwable ex) {
      //异常具体的处理，记录亦或上传到服务器
    }
}

实现Thread.UncaughtExceptionHandler接口当有未捕获的异常的时候会回调uncaughtException(Thread thread, Throwable ex)方法

设置自定的异常处理类为系统默认的

1	Thread.setDefaultUncaughtExceptionHandler(crashHandler);

以上就是大致的使用步骤

具体代码逻辑

在application中初始化

public class AppApplication extends Application {


    private static Context mContext;

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

    public static Context getContext(){
        return mContext;
    }
}

CrashHandler 实现类如下

public class CrashHandler implements Thread.UncaughtExceptionHandler {

    /**
     * 系统默认UncaughtExceptionHandler
     */
    private Thread.UncaughtExceptionHandler mDefaultHandler;

    /**
     * context
     */
    private Context mContext;

    /**
     * 存储异常和参数信息
     */
    private Map paramsMap = new HashMap<>();

    /**
     * 格式化时间
     */
    private SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");

    private String TAG = this.getClass().getSimpleName();

    private static CrashHandler mInstance;

    private CrashHandler() {

    }

    /**
     * 获取CrashHandler实例
     */
    public static synchronized CrashHandler getInstance(){
        if(null == mInstance){
            mInstance = new CrashHandler();
        }
        return mInstance;
    }

    public void init(Context context){
        mContext = context;
        mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();

        Thread.setDefaultUncaughtExceptionHandler(this);
    }

    /**
     * uncaughtException 回调函数
     */
    @Override
    public void uncaughtException(Thread thread, Throwable ex) {
        if(!handleException(ex) && mDefaultHandler != null){
            mDefaultHandler.uncaughtException(thread,ex);
        }else{
            try {
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                Log.e(TAG, "error : ", e);
            }

            AppManager.getAppManager().AppExit(mContext);
        }

    }

    /**
     * 收集错误信息.发送到服务器
     * @return 处理了该异常返回true,否则false
     */
    private boolean handleException(Throwable ex) {
        if (ex == null) {
            return false;
        }

        collectDeviceInfo(mContext);

        new Thread() {
            @Override
            public void run() {
                Looper.prepare();
                Toast.makeText(mContext, "程序开小差了呢..", Toast.LENGTH_SHORT).show();
                Looper.loop();
            }
        }.start();

        saveCrashInfo2File(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 + "";
                paramsMap.put("versionName", versionName);
                paramsMap.put("versionCode", versionCode);
            }
        } catch (PackageManager.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);
                paramsMap.put(field.getName(), field.get(null).toString());
            } 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 saveCrashInfo2File(Throwable ex) {

        StringBuffer sb = new StringBuffer();
        for (Map.Entry entry : paramsMap.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 = format.format(new Date());
            String fileName = "crash-" + time + "-" + timestamp + ".log";
            if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
                String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/crash/";
                File dir = new File(path);
                if (!dir.exists()) {
                    dir.mkdirs();
                }
                FileOutputStream fos = new FileOutputStream(path + fileName);
                fos.write(sb.toString().getBytes());
                fos.close();
            }
            return fileName;
        } catch (Exception e) {
            Log.e(TAG, "an error occured while writing file...", e);
        }
        return null;
    }
}

⚠️此处并未使用常用的退出应用代码

android.os.Process.killProcess(android.os.Process.myPid());
System.exit(1);
//区别在于：system.exit（0）:正常退出，程序正常执行结束退出,system.exit(1):是非正常退出，就是说无论程序正在执行与否，都退出，
//System.exit(status)不管status为何值都会退出程序。和return 相比有以下不同点：return是回到上一层，而System.exit(status)是回到最上层 */

具体原因为：在4.4即以上系统使用该方法杀进程的时候app会重启,类似内存不足app挂了，系统会发广播拉起app的那种情况，那么就有可能会导致一个异常多次上报的情况,所以这里实现的activity栈来管理退出.

activity管理类

public class AppManager {  


    private static Stack activityStack;  

    private static AppManager instance;  

    private AppManager() {  
    }  

    /**
     * 单一实例
     */  
    public static AppManager getAppManager() {  
        if (instance == null) {  
            instance = new AppManager();  
        }  
        return instance;  
    }  

    /**
     * 添加Activity到堆栈
     */  
    public void addActivity(Activity activity) {  
        if (activityStack == null) {  
            activityStack = new Stack();  
        }  
        activityStack.add(activity);  
    }  

    /**
     * 获取当前Activity（堆栈中最后一个压入的）
     */  
    public Activity currentActivity() {  
        Activity activity = activityStack.lastElement();  
        return activity;  
    }  

    /**
     * 结束当前Activity（堆栈中最后一个压入的）
     */  
    public void finishActivity() {  
        Activity activity = activityStack.lastElement();  
        finishActivity(activity);  
    }  

    /**
     * 结束指定的Activity
     */  
    public void finishActivity(Activity activity) {  
        if (activity != null) {  
            activityStack.remove(activity);  
            activity.finish();  
            activity = null;  
        }  
    }  

    /**
     * 结束指定类名的Activity
     */  
    public void finishActivity(Class cls) {  
        for (Activity activity : activityStack) {  
            if (activity.getClass().equals(cls)) {  
                finishActivity(activity);
                break;
            }  
        }  
    }  

    /**
     * 结束所有Activity
     */  
    public void finishAllActivity() {  
        for (int i = 0; i < activityStack.size(); i++) {  
            if (null != activityStack.get(i)) {  
                activityStack.get(i).finish();  
            }  
        }  
        activityStack.clear();  
    }  

    /**
     * 退出应用程序
     */  
    public void AppExit(Context context) {  
        try {  
            finishAllActivity();  
            ActivityManager activityMgr = (ActivityManager) context  
                    .getSystemService(Context.ACTIVITY_SERVICE);  
            activityMgr.killBackgroundProcesses(context.getPackageName());  
            System.exit(0);  
        } catch (Exception e) {  
        }  
    }  
}