CustomRelativeLayout.java

/*
 * Copyright (C) Winson Chiu
 *
 * 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 cw.kop.autobackground;

import android.content.Context;
import android.util.AttributeSet;
import android.view.ViewTreeObserver;
import android.widget.RelativeLayout;

/**
 * Created by TheKeeperOfPie on 11/3/2014.
 */
public class CustomRelativeLayout extends RelativeLayout {

    private float xFraction = 0;
    private float yFraction = 0;
    private ViewTreeObserver.OnPreDrawListener preDrawListener = null;

    public CustomRelativeLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public CustomRelativeLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomRelativeLayout(Context context) {
        super(context);
    }

    public float getYFraction() {
        if (getHeight() == 0) {
            return 0;
        }
        return getTranslationY() / getHeight();
    }

    public void setYFraction(float fraction) {
        this.yFraction = fraction;

        if (getHeight() == 0) {
            if (preDrawListener == null) {
                preDrawListener = new ViewTreeObserver.OnPreDrawListener() {
                    @Override
                    public boolean onPreDraw() {
                        getViewTreeObserver().removeOnPreDrawListener(preDrawListener);
                        setYFraction(yFraction);
                        setXFraction(xFraction);
                        return true;
                    }
                };
                getViewTreeObserver().addOnPreDrawListener(preDrawListener);
            }
            return;
        }

        float translationY = getHeight() * fraction;
        setTranslationY(translationY);
    }

    public float getXFraction() {
        if (getWidth() == 0) {
            return 0;
        }
        return getTranslationX() / getWidth();
    }

    public void setXFraction(float fraction) {
        this.xFraction = fraction;

        if (getWidth() == 0) {
            if (preDrawListener == null) {
                preDrawListener = new ViewTreeObserver.OnPreDrawListener() {
                    @Override
                    public boolean onPreDraw() {
                        getViewTreeObserver().removeOnPreDrawListener(preDrawListener);
                        setYFraction(yFraction);
                        setXFraction(xFraction);
                        return true;
                    }
                };
                getViewTreeObserver().addOnPreDrawListener(preDrawListener);
            }
            return;
        }

        float translationX = getWidth() * fraction;
        setTranslationX(translationX);
    }

}