Android Open Source - lucene Pan Controller

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License

The source code is released under:

GNU General Public License

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Java Source Code

/**
 * Copyright (C) 2011-2012 Takahiro Yoshimura
 *//w  w w.ja va2  s.  co m
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * AdMob library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 *
 * You must obey the GNU General Public License in all respects for
 * all of the code used other than AdMob.  If you modify file(s) with
 * this exception, you may extend this exception to your version of
 * the file(s), but you are not obligated to do so.  If you do not
 * wish to do so, delete this exception statement from your version.
 * If you delete this exception statement from all source files in the
 * program, then also delete it here.
 */

package com.gmail.altakey.lucene.motion;

import android.widget.ImageView;
import android.graphics.PointF;
import android.graphics.Matrix;
import android.view.MotionEvent;

public final class PanController
{
  private static final int UNLOCKED = -1;

  private final ImageView view;

  private int pointer_id = UNLOCKED;
  private float x;
  private float y;

  public PanController(final ImageView view)
  {
    this.view = view;
  }

  public void begin(final MotionEvent e)
  {
    if (this.pointer_id == UNLOCKED)
    {
      int index = e.getActionIndex();
      this.pointer_id = e.getPointerId(index);
      this.x = e.getX(index);
      this.y = e.getY(index);
    }
  }

  public void update(final MotionEvent e)
  {
    if (this.pointer_id != UNLOCKED)
    {
      int index = e.findPointerIndex(this.pointer_id);
      try
      {
        this.apply(e.getX(index) - this.x, e.getY(index) - this.y);
        this.x = e.getX(index);
        this.y = e.getY(index);
      }
      catch (IllegalArgumentException exc)
      {
        return;
      }
      catch (ArrayIndexOutOfBoundsException exc)
      {
        return;
      }
    }
  }

  public void end()
  {
    this.pointer_id = UNLOCKED;
    this.x = 0.0f;
    this.y = 0.0f;
  }

  private void apply(final float dx, final float dy)
  {
    Matrix m = new Matrix(this.view.getImageMatrix());
    m.postTranslate(dx, dy);
    this.view.setImageMatrix(m);
  }
}

Java Source Code List