WheelHorizontalView.java

/*
 * android-spinnerwheel
 * https://github.com/ai212983/android-spinnerwheel
 *
 * based on
 *
 * Android Wheel Control.
 * https://code.google.com/p/android-wheel/
 *
 * Copyright 2011 Yuri Kanivets
 *
 * 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 org.droidplanner.android.view.spinnerWheel;

import org.droidplanner.android.R;
import org.droidplanner.android.view.spinnerWheel.adapters.AbstractWheelTextAdapter;
import org.droidplanner.android.view.spinnerWheel.adapters.NumericWheelAdapter;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Shader;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;

/**
 * Spinner wheel horizontal view.
 * 
 * @author Yuri Kanivets
 * @author Dimitri Fedorov
 */
public class WheelHorizontalView<T> extends AbstractWheelView {

	@SuppressWarnings("unused")
	private final String LOG_TAG = WheelHorizontalView.class.getSimpleName();

	/**
	 * The width of the selection divider.
	 */
	protected int mSelectionDividerWidth;

	// Item width
	private int itemWidth = 0;

	// --------------------------------------------------------------------------
	//
	// Constructors
	//
	// --------------------------------------------------------------------------

	/**
	 * Create a new wheel horizontal view.
	 * 
	 * @param context
	 *            The application environment.
	 */
	public WheelHorizontalView(Context context) {
		this(context, null);
	}

	/**
	 * Create a new wheel horizontal view.
	 * 
	 * @param context
	 *            The application environment.
	 * @param attrs
	 *            A collection of attributes.
	 */
	public WheelHorizontalView(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	/**
	 * Create a new wheel horizontal view.
	 * 
	 * @param context
	 *            the application environment.
	 * @param attrs
	 *            a collection of attributes.
	 * @param defStyle
	 *            The default style to apply to this view.
	 */
	public WheelHorizontalView(final Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);

		// Create a dummy view adapter if we're in edit mode.
		if (isInEditMode()) {
			final NumericWheelAdapter adapter = new NumericWheelAdapter(context, 0, 100);
			adapter.setItemResource(R.layout.wheel_text_centered);
			setViewAdapter(adapter);
			setCurrentItem(50);
		}
	}

	@Override
	public void onDetachedFromWindow() {
		super.onDetachedFromWindow();
	}

	// --------------------------------------------------------------------------
	//
	// Initiating assets and setter for selector paint
	//
	// --------------------------------------------------------------------------

	@Override
	protected void initAttributes(AttributeSet attrs, int defStyle) {
		super.initAttributes(attrs, defStyle);

		TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.WheelHorizontalView,
				defStyle, 0);
		mSelectionDividerWidth = a.getDimensionPixelSize(
				R.styleable.WheelHorizontalView_selectionDividerWidth, DEF_SELECTION_DIVIDER_SIZE);
		a.recycle();
	}

	public void setSelectionDividerWidth(int selectionDividerWidth) {
		this.mSelectionDividerWidth = selectionDividerWidth;
	}

	@Override
	public void setSelectorPaintCoeff(float coeff) {
		LinearGradient shader;

		int w = getMeasuredWidth();
		int iw = getItemDimension();
		float p1 = (1 - iw / (float) w) / 2;
		float p2 = (1 + iw / (float) w) / 2;
		float z = mItemsDimmedAlpha * (1 - coeff);
		float c1f = z + 255 * coeff;

		if (mVisibleItems == 2) {
			int c1 = Math.round(c1f) << 24;
			int c2 = Math.round(z) << 24;
			int[] colors = { c2, c1, 0xff000000, 0xff000000, c1, c2 };
			float[] positions = { 0, p1, p1, p2, p2, 1 };
			shader = new LinearGradient(0, 0, w, 0, colors, positions, Shader.TileMode.CLAMP);
		} else {
			float p3 = (1 - iw * 3 / (float) w) / 2;
			float p4 = (1 + iw * 3 / (float) w) / 2;

			float s = 255 * p3 / p1;
			float c3f = s * coeff; // here goes some optimized stuff
			float c2f = z + c3f;

			int c1 = Math.round(c1f) << 24;
			int c2 = Math.round(c2f) << 24;
			int c3 = Math.round(c3f) << 24;

			int[] colors = { c2, c2, c2, c2, 0xff000000, 0xff000000, c2, c2, c2, c2 };
			float[] positions = { 0, p3, p3, p1, p1, p2, p2, p4, p4, 1 };
			shader = new LinearGradient(0, 0, w, 0, colors, positions, Shader.TileMode.CLAMP);
		}
		mSelectorWheelPaint.setShader(shader);
		invalidate();
	}

	// --------------------------------------------------------------------------
	//
	// Scroller-specific methods
	//
	// --------------------------------------------------------------------------

	@Override
	protected WheelScroller createScroller(WheelScroller.ScrollingListener scrollingListener) {
		return new WheelHorizontalScroller(getContext(), scrollingListener);
	}

	@Override
	protected float getMotionEventPosition(MotionEvent event) {
		return event.getX();
	}

	// --------------------------------------------------------------------------
	//
	// Base measurements
	//
	// --------------------------------------------------------------------------

	@Override
	protected int getBaseDimension() {
		return getWidth();
	}

	/**
	 * Returns height of spinnerwheel item
	 * 
	 * @return the item width
	 */
	@Override
	protected int getItemDimension() {
		if (itemWidth != 0) {
			return itemWidth;
		}

		if (mItemsLayout != null && mItemsLayout.getChildAt(0) != null) {
			itemWidth = mItemsLayout.getChildAt(0).getMeasuredWidth();
			return itemWidth;
		}

		return getBaseDimension() / mVisibleItems;
	}

	public void setViewAdapter(AbstractWheelTextAdapter<T> viewAdapter) {
		super.setViewAdapter(viewAdapter);
	}

	public AbstractWheelTextAdapter<T> getViewAdapter() {
		return (AbstractWheelTextAdapter<T>) mViewAdapter;
	}

	// --------------------------------------------------------------------------
	//
	// Layout creation and measurement operations
	//
	// --------------------------------------------------------------------------

	/**
	 * Creates item layouts if necessary
	 */
	@Override
	protected void createItemsLayout() {
		if (mItemsLayout == null) {
			mItemsLayout = new LinearLayout(getContext());
			mItemsLayout.setOrientation(LinearLayout.HORIZONTAL);
		}
	}

	@Override
	protected void doItemsLayout() {
		mItemsLayout.layout(0, 0, getMeasuredWidth(), getMeasuredHeight() - 2 * mItemsPadding);
	}

	@Override
	protected void measureLayout() {
		mItemsLayout.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
				LayoutParams.WRAP_CONTENT));
		// XXX: Locating bug
		mItemsLayout.measure(View.MeasureSpec.makeMeasureSpec(getWidth() + getItemDimension(),
				View.MeasureSpec.UNSPECIFIED), View.MeasureSpec.makeMeasureSpec(getHeight(),
				View.MeasureSpec.AT_MOST));
	}

	// XXX: Most likely, measurements of mItemsLayout or/and its children are
	// done inconrrectly.
	// Investigate and fix it

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		int widthMode = View.MeasureSpec.getMode(widthMeasureSpec);
		int heightMode = View.MeasureSpec.getMode(heightMeasureSpec);
		int widthSize = View.MeasureSpec.getSize(widthMeasureSpec);
		int heightSize = View.MeasureSpec.getSize(heightMeasureSpec);

		rebuildItems(); // rebuilding before measuring

		int height = calculateLayoutHeight(heightSize, heightMode);

		int width;
		if (widthMode == View.MeasureSpec.EXACTLY) {
			width = widthSize;
		} else {
			width = Math.max(getItemDimension() * (mVisibleItems - mItemOffsetPercent / 100),
					getSuggestedMinimumWidth());

			if (widthMode == View.MeasureSpec.AT_MOST) {
				width = Math.min(width, widthSize);
			}
		}
		setMeasuredDimension(width, height);
	}

	/**
	 * Calculates control height and creates text layouts
	 * 
	 * @param heightSize
	 *            the input layout height
	 * @param mode
	 *            the layout mode
	 * @return the calculated control height
	 */
	private int calculateLayoutHeight(int heightSize, int mode) {
		mItemsLayout.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
				LayoutParams.WRAP_CONTENT));
		mItemsLayout.measure(View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
				View.MeasureSpec.makeMeasureSpec(heightSize, View.MeasureSpec.UNSPECIFIED));
		int height = mItemsLayout.getMeasuredHeight();

		if (mode == View.MeasureSpec.EXACTLY) {
			height = heightSize;
		} else {
			height += 2 * mItemsPadding;

			// Check against our minimum width
			height = Math.max(height, getSuggestedMinimumHeight());

			if (mode == View.MeasureSpec.AT_MOST && heightSize < height) {
				height = heightSize;
			}
		}
		// forcing recalculating
		mItemsLayout.measure(
		// MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
				View.MeasureSpec.makeMeasureSpec(400, View.MeasureSpec.EXACTLY), View.MeasureSpec
						.makeMeasureSpec(height - 2 * mItemsPadding, View.MeasureSpec.EXACTLY));

		return height;
	}

	// --------------------------------------------------------------------------
	//
	// Drawing items
	//
	// --------------------------------------------------------------------------

	@Override
	protected void drawItems(Canvas canvas) {
		canvas.save();
		int w = getMeasuredWidth();
		int h = getMeasuredHeight();
		int iw = getItemDimension();

		// resetting intermediate bitmap and recreating canvases
		mSpinBitmap.eraseColor(0);
		Canvas c = new Canvas(mSpinBitmap);
		Canvas cSpin = new Canvas(mSpinBitmap);

		int left = (mCurrentItemIdx - mFirstItemIdx) * iw + (iw - getWidth()) / 2;
		c.translate(-left + mScrollingOffset, mItemsPadding);
		mItemsLayout.draw(c);

		mSeparatorsBitmap.eraseColor(0);
		Canvas cSeparators = new Canvas(mSeparatorsBitmap);

		if (mSelectionDivider != null) {
			// draw the top divider
			int leftOfLeftDivider = (getWidth() - iw - mSelectionDividerWidth) / 2;
			int rightOfLeftDivider = leftOfLeftDivider + mSelectionDividerWidth;
			cSeparators.save();
			// On Gingerbread setBounds() is ignored resulting in an ugly visual
			// bug.
			cSeparators.clipRect(leftOfLeftDivider, 0, rightOfLeftDivider, h);
			mSelectionDivider.setBounds(leftOfLeftDivider, 0, rightOfLeftDivider, h);
			mSelectionDivider.draw(cSeparators);
			cSeparators.restore();

			cSeparators.save();
			// draw the bottom divider
			int leftOfRightDivider = leftOfLeftDivider + iw;
			int rightOfRightDivider = rightOfLeftDivider + iw;
			// On Gingerbread setBounds() is ignored resulting in an ugly visual
			// bug.
			cSeparators.clipRect(leftOfRightDivider, 0, rightOfRightDivider, h);
			mSelectionDivider.setBounds(leftOfRightDivider, 0, rightOfRightDivider, h);
			mSelectionDivider.draw(cSeparators);
			cSeparators.restore();
		}

		cSpin.drawRect(0, 0, w, h, mSelectorWheelPaint);
		cSeparators.drawRect(0, 0, w, h, mSeparatorsPaint);

		canvas.drawBitmap(mSpinBitmap, 0, 0, null);
		canvas.drawBitmap(mSeparatorsBitmap, 0, 0, null);
		canvas.restore();
	}

}