ForegroundRelativeLayout.java

/*
 * Copyright 2015 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 io.plaidapp.ui.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.ViewOutlineProvider;
import android.widget.RelativeLayout;

import io.plaidapp.R;

/**
 * An extension to {@link RelativeLayout} which has a foreground drawable.
 */
public class ForegroundRelativeLayout extends RelativeLayout {

    private Drawable foreground;

    public ForegroundRelativeLayout(Context context, AttributeSet attrs) {
        super(context, attrs);

        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ForegroundView);

        final Drawable d = a.getDrawable(R.styleable.ForegroundView_android_foreground);
        if (d != null) {
            setForeground(d);
        }
        a.recycle();
        setOutlineProvider(ViewOutlineProvider.BOUNDS);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        if (foreground != null) {
            foreground.setBounds(0, 0, w, h);
        }
    }

    @Override
    public boolean hasOverlappingRendering() {
        return false;
    }

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

    @Override
    public void jumpDrawablesToCurrentState() {
        super.jumpDrawablesToCurrentState();
        if (foreground != null) foreground.jumpToCurrentState();
    }

    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        if (foreground != null && foreground.isStateful()) {
            foreground.setState(getDrawableState());
        }
    }

    /**
     * Returns the drawable used as the foreground of this view. 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;
    }

    /**
     * Supply a Drawable that is to be rendered on top of all of the child
     * views within this layout.  Any padding in the Drawable will be taken
     * into account by ensuring that the children are inset to be placed
     * inside of the padding area.
     *
     * @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 (foreground != null) {
                foreground.setBounds(getLeft(), getTop(), getRight(), getBottom());
                setWillNotDraw(false);
                foreground.setCallback(this);
                if (foreground.isStateful()) {
                    foreground.setState(getDrawableState());
                }
            } else {
                setWillNotDraw(true);
            }
            invalidate();
        }
    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        if (foreground != null) {
            foreground.draw(canvas);
        }
    }

    @Override
    public void drawableHotspotChanged(float x, float y) {
        super.drawableHotspotChanged(x, y);
        if (foreground != null) {
            foreground.setHotspot(x, y);
        }
    }
}