DragGripView.java

/**
 * Copyright (C) 2013 Romain Guefveneu.
 *   
 *  This file is part of naonedbus.
 *   
 *  Naonedbus 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.
 *  
 *  Naonedbus 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/>.
 */
/*
 * Copyright 2013 Google Inc.
 *
 * 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 net.naonedbus.widget;

import net.naonedbus.R;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;

public class DragGripView extends View {
	private static final int[] ATTRS = new int[] { android.R.attr.gravity, android.R.attr.color, };

	private static final int HORIZ_RIDGES = 2;

	private int mGravity = Gravity.LEFT;
	private int mColor = 0x33333333;

	private final Paint mRidgePaint;

	private final float mRidgeSize;
	private final float mRidgeGap;

	private int mWidth;
	private int mHeight;

	public DragGripView(final Context context) {
		this(context, null, 0);
	}

	public DragGripView(final Context context, final AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public DragGripView(final Context context, final AttributeSet attrs, final int defStyle) {
		super(context, attrs, defStyle);

		final TypedArray a = context.obtainStyledAttributes(attrs, ATTRS);
		mGravity = a.getInteger(0, mGravity);
		mColor = a.getColor(1, mColor);
		a.recycle();

		final Resources res = getResources();
		mRidgeSize = res.getDimensionPixelSize(R.dimen.drag_grip_ridge_size);
		mRidgeGap = res.getDimensionPixelSize(R.dimen.drag_grip_ridge_gap);

		mRidgePaint = new Paint();
		mRidgePaint.setColor(mColor);
	}

	@Override
	protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) {
		setMeasuredDimension(
				View.resolveSize((int) (HORIZ_RIDGES * (mRidgeSize + mRidgeGap) - mRidgeGap) + getPaddingLeft()
						+ getPaddingRight(), widthMeasureSpec), View.resolveSize((int) mRidgeSize, heightMeasureSpec));
	}

	@Override
	protected void onDraw(final Canvas canvas) {
		super.onDraw(canvas);

		final float drawWidth = HORIZ_RIDGES * (mRidgeSize + mRidgeGap) - mRidgeGap;
		float drawLeft;

		switch (mGravity & Gravity.HORIZONTAL_GRAVITY_MASK) {
		case Gravity.CENTER_HORIZONTAL:
			drawLeft = getPaddingLeft() + ((mWidth - getPaddingLeft() - getPaddingRight()) - drawWidth) / 2;
			break;
		case Gravity.RIGHT:
			drawLeft = getWidth() - getPaddingRight() - drawWidth;
			break;
		default:
			drawLeft = getPaddingLeft();
		}

		final int vertRidges = (int) ((mHeight - getPaddingTop() - getPaddingBottom() + mRidgeGap) / (mRidgeSize + mRidgeGap));
		final float drawHeight = vertRidges * (mRidgeSize + mRidgeGap) - mRidgeGap;
		final float drawTop = getPaddingTop() + ((mHeight - getPaddingTop() - getPaddingBottom()) - drawHeight) / 2;

		for (int y = 0; y < vertRidges; y++) {
			for (int x = 0; x < HORIZ_RIDGES; x++) {
				canvas.drawRect(drawLeft + x * (mRidgeSize + mRidgeGap), drawTop + y * (mRidgeSize + mRidgeGap),
						drawLeft + x * (mRidgeSize + mRidgeGap) + mRidgeSize, drawTop + y * (mRidgeSize + mRidgeGap)
								+ mRidgeSize, mRidgePaint);
			}
		}
	}

	@Override
	protected void onSizeChanged(final int w, final int h, final int oldw, final int oldh) {
		super.onSizeChanged(w, h, oldw, oldh);
		mHeight = h;
		mWidth = w;
	}
}