【移动开发】捕获异常信息_UncaughtExceptionHandler

当程序崩溃（Crash）的时候，默认是不对异常信息做处理的。如果想要把异常信息保存到本地文件中，或上传的服务器。那么就要借助UncaughtExceptionHandler这个类。

首先，实例化UncaughtExceptionHandler，代码如下：

public class ForceCloseHandler implements Thread.UncaughtExceptionHandler {

    public static final String LOG_FILE_NAME = "forceclose.log";

    private static ForceCloseHandler inst ;
    public static ForceCloseHandler getInstance() {
        if(inst==null)inst = new ForceCloseHandler();
        return inst;
    }


    private Context mContext;
    private Thread.UncaughtExceptionHandler mExceptionHandler;
    private JSONObject jsonObject;
    private ForceCloseHandler() {}

    public void init(Context context) {
        mContext = context;
        mExceptionHandler = Thread.getDefaultUncaughtExceptionHandler();
        Thread.setDefaultUncaughtExceptionHandler(this);
    }


    private void handleUncaughtException(Throwable ex) {
        if (ex == null) return;
        try {
            if(jsonObject ==null)jsonObject = new JSONObject();
            saveDeviceInfo();
            saveForceCloseInfo2File(ex);
            // 把异常信息发送到服务器
            ForceCloseFeedBack.getInstance().feedBack(mContext, jsonObject.toString());
        } catch (Exception e) {
            LogUtil.w(e);
        }
    }

    @Override
    public void uncaughtException(Thread thread, Throwable throwable) {
        handleUncaughtException(throwable);
        if (throwable != null) LogUtil.w(throwable);
        mExceptionHandler.uncaughtException(thread, throwable);
    }

    public void saveDeviceInfo() throws JSONException {
        TelephonyManager tm = (TelephonyManager) mContext.getSystemService(Context.TELEPHONY_SERVICE);

        jsonObject.put("platform", "android");
        jsonObject.put("model", Build.MODEL);
        jsonObject.put("trackid", AppConfig.PARTNER_ID);
        jsonObject.put("product", AppConfig.CLIENT_TAG);
        jsonObject.put("os_version", Build.VERSION.RELEASE);
        jsonObject.put("deviceid", DeviceInfo.getDeviceId());
        jsonObject.put("net_type", tm.getNetworkOperator());
        jsonObject.put("timestamp", System.currentTimeMillis());
        jsonObject.put("app_version", Application.getInstance().getVersionCode());
    }

    private void saveForceCloseInfo2File(Throwable ex) throws Exception {
        StringWriter 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() + "\n";
        jsonObject.put("errorDetail", result);

        if (AppConfig.LOG_ERR_SAVE) {
            File file = FileHelper.getDiskCacheDir(mContext, LOG_FILE_NAME);
            FileOutputStream fos = new FileOutputStream(file, true);
            fos.write(jsonObject.toString().getBytes());
            fos.close();
        }
    }

}

接下来，看看这个实例化后的类怎么使用，代码如下：

public class Application extends android.app.Application {

    private static Application instance;

    public Context currentContext;

    public static Application getInstance() {
        return instance;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        init();
    }

    public void init() {
        instance = this;

        if (Config.LOG_ERR_FEED) { 
            ForceCloseHandler.getInstance().init(instance);
        }
    }

    @Override
    public void onTerminate() {
        super.onTerminate();
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
    }

}

非常简单，只要在指定的Application类的onCreate()回调中，把UncaughtExceptionHandler和Application的实例绑定在一起就可以了。关键代码如下：

    public void init(Context context) {
        mContext = context;
        mExceptionHandler = Thread.getDefaultUncaughtExceptionHandler();
        Thread.setDefaultUncaughtExceptionHandler(this);
    }

这样，如果程序崩溃，错误日志就会被保存在本地，同时又被上传到了服务器。