Android Open Source - qrcode-android Auto Focus Manager

From Project

Back to project page qrcode-android.
License

The source code is released under:
MIT License
If you think the Android project qrcode-android listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.
Java Source Code

/*
 * Copyright (C) 2012 ZXing authors/*from  www .j a va 2s.  c  o  m*/
 *
 * 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.google.zxing.client.android.camera;

import android.content.Context;
import android.hardware.Camera;
import android.os.AsyncTask;
import android.util.Log;
import com.google.zxing.client.android.common.executor.AsyncTaskExecInterface;
import com.google.zxing.client.android.common.executor.AsyncTaskExecManager;
import eu.livotov.zxscan.ZXScanHelper;

import java.util.ArrayList;
import java.util.Collection;

final class AutoFocusManager implements Camera.AutoFocusCallback
{

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

    private static final long AUTO_FOCUS_INTERVAL_MS = 2000L;
    private static final Collection<String> FOCUS_MODES_CALLING_AF;

    static
    {
        FOCUS_MODES_CALLING_AF = new ArrayList<String>(2);
        FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_AUTO);
        FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_MACRO);
    }

    private boolean active;
    private boolean useAutoFocus = true;
    private final Camera camera;
    private AutoFocusTask outstandingTask;
    private final AsyncTaskExecInterface taskExec;

    AutoFocusManager(Context context, Camera camera)
    {
        this.camera = camera;
        taskExec = new AsyncTaskExecManager().build();
        String currentFocusMode = camera.getParameters().getFocusMode();

        switch (ZXScanHelper.getAutofocusMode())
        {
            case Auto:
                useAutoFocus = true && FOCUS_MODES_CALLING_AF.contains(currentFocusMode);
                break;

            case On:
                useAutoFocus = true;
                break;

            case Off:
                useAutoFocus = false;
        }

        Log.i(TAG, "Current focus mode '" + currentFocusMode + "'; use auto focus? " + useAutoFocus);
        start();
    }

    @Override
    public synchronized void onAutoFocus(boolean success, Camera theCamera)
    {
        if (active)
        {
            outstandingTask = new AutoFocusTask();
            taskExec.execute(outstandingTask);
        }
    }

    synchronized void start()
    {
        if (useAutoFocus)
        {
            active = true;
            try
            {
                camera.autoFocus(this);
            } catch (RuntimeException re)
            {
                // Have heard RuntimeException reported in Android 4.0.x+; continue?
                Log.w(TAG, "Unexpected exception while focusing", re);
            }
        }
    }

    synchronized void stop()
    {
        if (useAutoFocus)
        {
            try
            {
                camera.cancelAutoFocus();
            } catch (RuntimeException re)
            {
                // Have heard RuntimeException reported in Android 4.0.x+; continue?
                Log.w(TAG, "Unexpected exception while cancelling focusing", re);
            }
        }
        if (outstandingTask != null)
        {
            outstandingTask.cancel(true);
            outstandingTask = null;
        }
        active = false;
    }

    private final class AutoFocusTask extends AsyncTask<Object, Object, Object>
    {

        @Override
        protected Object doInBackground(Object... voids)
        {
            try
            {
                Thread.sleep(AUTO_FOCUS_INTERVAL_MS);
            } catch (InterruptedException e)
            {
                // continue
            }
            synchronized (AutoFocusManager.this)
            {
                if (active)
                {
                    start();
                }
            }
            return null;
        }
    }

}
Java Source Code List
