Android Open Source - CamView Auto Focus Manager

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License

The source code is released under:

Apache License

Java Source Code

package eu.livotov.labs.android.camview;
// w ww .j  a  v  a2  s.c o m
import android.content.Context;
import android.hardware.Camera;
import android.util.Log;

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 final boolean useAutoFocus;
    private final Camera camera;
    private boolean active;
    private CAMViewAsyncTask<?, ?, ?> outstandingTask;

    AutoFocusManager(Context context, Camera camera)
    {
        this.camera = camera;
        String currentFocusMode = camera.getParameters().getFocusMode();
        useAutoFocus = FOCUS_MODES_CALLING_AF.contains(currentFocusMode);
        Log.d(TAG, "Current focus mode '" + currentFocusMode + "'; use auto focus? " + useAutoFocus);
        start();
    }

    @SuppressWarnings("unchecked")
    @Override
    public synchronized void onAutoFocus(boolean success, Camera theCamera)
    {
        if (active)
        {
            outstandingTask = new AutoFocusTask();
            outstandingTask.execPool();
        }
    }

    synchronized void start()
    {
        if (useAutoFocus)
        {
            active = true;
            try
            {
                camera.autoFocus(this);
            } catch (Throwable re)
            {
                Log.w(TAG, "Unexpected exception while focusing", re);
            }
        }
    }

    synchronized void stop()
    {
        if (useAutoFocus)
        {
            try
            {
                camera.cancelAutoFocus();
            } catch (Throwable re)
            {
                Log.w(TAG, "Unexpected exception while cancelling focusing", re);
            }
        }

        if (outstandingTask != null)
        {
            outstandingTask.cancel();
            outstandingTask = null;
        }
        active = false;
    }


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

        @Override
        protected Object doInBackground(Object... voids)
        {
            try
            {
                Thread.sleep(AUTO_FOCUS_INTERVAL_MS);
            } catch (InterruptedException ignored)
            {
            }

            synchronized (AutoFocusManager.this)
            {
                if (active)
                {
                    start();
                }
            }
            return null;
        }
    }

}

Java Source Code List

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