ForegroundImageView.java

/*
 * Copyright 2014 DogmaLabs
 *
 * 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.boardgamegeek.ui.widget;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.NinePatchDrawable;
import android.os.Build;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.support.annotation.NonNull;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.ImageView;

import com.boardgamegeek.R;

public class ForegroundImageView extends ImageView {

	// UI
	private Drawable foreground;

	// Controller/logic fields
	private final Rect rectPadding = new Rect();
	private boolean foregroundPadding = false;
	private boolean foregroundBoundsChanged = false;

	// Constructors
	public ForegroundImageView(Context context) {
		super(context);
	}

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

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

		final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ForegroundImageView, defStyle, 0);

		final Drawable d = a.getDrawable(R.styleable.ForegroundImageView_android_foreground);
		foregroundPadding = a.getBoolean(R.styleable.ForegroundImageView_android_foregroundInsidePadding, false);

		// Apply foreground padding for nine patches automatically
		if (!foregroundPadding && getBackground() instanceof NinePatchDrawable) {
			final NinePatchDrawable npd = (NinePatchDrawable) getBackground();
			if (npd != null && npd.getPadding(rectPadding)) {
				foregroundPadding = true;
			}
		}

		setForeground(d);

		a.recycle();
	}

	/**
	 * Supply a Drawable that is to be rendered on top of all of the child views in the layout.
	 *
	 * @param drawable The Drawable to be drawn on top of the children.
	 */
	public void setForeground(Drawable drawable) {
		if (foreground != drawable) {
			if (foreground != null) {
				foreground.setCallback(null);
				unscheduleDrawable(foreground);
			}

			foreground = drawable;

			if (drawable != null) {
				setWillNotDraw(false);
				drawable.setCallback(this);
				if (drawable.isStateful()) {
					drawable.setState(getDrawableState());
				}
			} else {
				setWillNotDraw(true);
			}
			requestLayout();
			invalidate();
		}
	}

	/**
	 * Returns the drawable used as the foreground of this layout. The foreground drawable,
	 * if non-null, is always drawn on top of the children.
	 *
	 * @return A Drawable or null if no foreground was set.
	 */
	public Drawable getForeground() {
		return foreground;
	}

	@Override
	protected void drawableStateChanged() {
		super.drawableStateChanged();

		if (foreground != null && foreground.isStateful()) {
			foreground.setState(getDrawableState());
		}
	}

	@Override
	protected boolean verifyDrawable(@NonNull Drawable who) {
		return super.verifyDrawable(who) || (who == foreground);
	}

	@Override
	public void jumpDrawablesToCurrentState() {
		super.jumpDrawablesToCurrentState();

		if (foreground != null) {
			foreground.jumpToCurrentState();
		}
	}

	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh) {
		super.onSizeChanged(w, h, oldw, oldh);
		foregroundBoundsChanged = true;
	}

	@Override
	public void draw(Canvas canvas) {
		super.draw(canvas);

		if (foreground != null) {
			final Drawable foreground = this.foreground;

			if (foregroundBoundsChanged) {
				foregroundBoundsChanged = false;

				final int w = getRight() - getLeft();
				final int h = getBottom() - getTop();

				if (foregroundPadding) {
					foreground.setBounds(rectPadding.left, rectPadding.top, w - rectPadding.right, h - rectPadding.bottom);
				} else {
					foreground.setBounds(0, 0, w, h);
				}
			}
			foreground.draw(canvas);
		}
	}

	@TargetApi(Build.VERSION_CODES.LOLLIPOP)
	@Override
	public boolean onTouchEvent(MotionEvent e) {
		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
			if (e.getActionMasked() == MotionEvent.ACTION_DOWN) {
				if (foreground != null) {
					foreground.setHotspot(e.getX(), e.getY());
				}
			}
		}
		return super.onTouchEvent(e);
	}

	@Override
	public void drawableHotspotChanged(float x, float y) {
		super.drawableHotspotChanged(x, y);
		if (VERSION.SDK_INT >= VERSION_CODES.LOLLIPOP && foreground != null) {
			foreground.setHotspot(x, y);
		}
	}
}