DecoderActivityHandler.java

/*
 * Copyright (C) 2008 ZXing authors
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.jwetherell.quick_response_code;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

import java.util.Collection;

import com.jwetherell.quick_response_code.R;
import com.jwetherell.quick_response_code.camera.CameraManager;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.Result;

/**
 * This class handles all the messaging which comprises the state machine for
 * capture.
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 */
public final class DecoderActivityHandler extends Handler {

    private static final String TAG = DecoderActivityHandler.class.getSimpleName();

    private final IDecoderActivity activity;
    private final DecodeThread decodeThread;
    private final CameraManager cameraManager;
    private State state;

    private enum State {
        PREVIEW, SUCCESS, DONE
    }

    public DecoderActivityHandler(IDecoderActivity activity, Collection<BarcodeFormat> decodeFormats, String characterSet,
            CameraManager cameraManager) {
        this.activity = activity;
        decodeThread = new DecodeThread(activity, decodeFormats, characterSet, new ViewfinderResultPointCallback(
                activity.getViewfinder()));
        decodeThread.start();
        state = State.SUCCESS;

        // Start ourselves capturing previews and decoding.
        this.cameraManager = cameraManager;
        cameraManager.startPreview();
        restartPreviewAndDecode();
    }

    @Override
    public void handleMessage(Message message) {
        if ( message.what == R.id.auto_focus ) {
         // Log.d(TAG, "Got auto-focus message");
          // When one auto focus pass finishes, start another. This is the
          // closest thing to
          // continuous AF. It does seem to hunt a bit, but I'm not sure
          // what else to do.
          if (state == State.PREVIEW) cameraManager.requestAutoFocus(this, R.id.auto_focus);
      } else if ( message.what == R.id.restart_preview ) {
         Log.d(TAG, "Got restart preview message");
         restartPreviewAndDecode();
      } else if ( message.what == R.id.decode_succeeded ) {
         Log.d(TAG, "Got decode succeeded message");
         state = State.SUCCESS;
         Bundle bundle = message.getData();
         Bitmap barcode = bundle == null ? null : (Bitmap) bundle.getParcelable(DecodeThread.BARCODE_BITMAP);
         activity.handleDecode((Result) message.obj, barcode);
      } else if ( message.what == R.id.decode_failed ) {
         // We're decoding as fast as possible, so when one decode fails,
          // start another.
          state = State.PREVIEW;
         cameraManager.requestPreviewFrame(decodeThread.getHandler(), R.id.decode);
      } else if ( message.what == R.id.return_scan_result ) {
         Log.d(TAG, "Got return scan result message");
         if (activity instanceof Activity) {
              ((Activity) activity).setResult(Activity.RESULT_OK, (Intent) message.obj);
              ((Activity) activity).finish();
          } else {
              Log.e(TAG, "Scan result message, activity is not Activity. Doing nothing.");
          }
      }
    }

    public void quitSynchronously() {
        state = State.DONE;
        cameraManager.stopPreview();
        Message quit = Message.obtain(decodeThread.getHandler(), R.id.quit);
        quit.sendToTarget();
        try {
            // Wait at most half a second; should be enough time, and onPause()
            // will timeout quickly
            decodeThread.join(500L);
        } catch (InterruptedException e) {
            // continue
        }

        // Be absolutely sure we don't send any queued up messages
        removeMessages(R.id.decode_succeeded);
        removeMessages(R.id.decode_failed);
    }

    public void restartPreviewAndDecode() {
        if (state == State.SUCCESS) {
            state = State.PREVIEW;
            cameraManager.requestPreviewFrame(decodeThread.getHandler(), R.id.decode);
            cameraManager.requestAutoFocus(this, R.id.auto_focus);
            activity.getViewfinder().drawViewfinder();
        }
    }
}