BaseStackBarChartView.java

/*
 * Copyright 2014 Diogo Bernardino
 *
 * 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.db.chart.view;

import android.content.Context;
import android.util.AttributeSet;

import com.db.chart.model.Bar;
import com.db.chart.model.BarSet;
import com.db.chart.model.ChartSet;

import java.util.ArrayList;


/**
 * Implements a bar chart extending {@link com.db.chart.view.BaseStackBarChartView}
 */
public abstract class BaseStackBarChartView extends BaseBarChartView {


    /**
     * Whether to calculate max value or not
     */
    protected boolean mCalcMaxValue;


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

        mCalcMaxValue = true;
    }


    public BaseStackBarChartView(Context context) {
        super(context);

        mCalcMaxValue = true;
    }


    /**
     * Calculates Bar width based on the distance of two horizontal labels.
     *
     * @param nSets Number of sets (not really necessary for stack bars)
     * @param x0    Coordinate(n)
     * @param x1    Coordinate(n+1)
     */
    @Override
    protected void calculateBarsWidth(int nSets, float x0, float x1) {
        barWidth = x1 - x0 - style.barSpacing;
    }


    /**
     * Finds the set that will stay in the bottom of the bar.
     *
     * @param entryIndex Entry index
     * @param data       {@link java.util.ArrayList} of {@link com.db.chart.model.ChartSet}
     *                   to use while drawing the Chart
     * @return The bottom set index
     */
    protected static int discoverBottomSet(int entryIndex, ArrayList<ChartSet> data) {

        int dataSize = data.size();
        int index;

        boolean hasNegativeValues = false;
        for (index = 0; index < dataSize; index++) {
            if (data.get(index).getEntry(entryIndex).getValue() < 0) {
                hasNegativeValues = true;
                break;
            }
        }

        if (hasNegativeValues) { // Find last value < 0
            for (index = dataSize - 1; index >= 0; index--) {
                if (data.get(index).getEntry(entryIndex).getValue() < 0)
                    break;
            }
        } else { // Find first non null value
            for (index = 0; index < dataSize; index++) {
                if (data.get(index).getEntry(entryIndex).getValue() != 0)
                    break;
            }
        }
        return index;
    }


    /**
     * Finds the set that will be on top.
     *
     * @param entryIndex Entry index
     * @param data       {@link java.util.ArrayList} of {@link com.db.chart.model.ChartSet}
     *                   to use while drawing the Chart
     * @return The top set index
     */
    protected static int discoverTopSet(int entryIndex, ArrayList<ChartSet> data) {

        int dataSize = data.size();
        int index;

        boolean hasPositiveValues = false;
        for (index = 0; index < dataSize; index++) {
            if (data.get(index).getEntry(entryIndex).getValue() > 0) {
                hasPositiveValues = true;
                break;
            }
        }

        if (hasPositiveValues) { // Find last value > 0
            for (index = dataSize - 1; index >= 0; index--)
                if (data.get(index).getEntry(entryIndex).getValue() > 0)
                    break;
        } else { // Find first non null value
            for (index = 0; index < dataSize; index++) {
                if (data.get(index).getEntry(entryIndex).getValue() != 0)
                    break;
            }
        }
        return index;
    }


    /**
     * This method will calculate what needs to be the max axis value that fits all the sets
     * aggregated, one on top of the other.
     */
    protected void calculateMaxStackBarValue() {

        float positiveStackValue;
        float negativeStackValue;
        BarSet barSet;
        Bar bar;
        int maxStackValue = 0;
        int minStackValue = 0;

        int dataSize = data.size();
        int setSize = data.get(0).size();

        for (int i = 0; i < setSize; i++) {

            positiveStackValue = 0;
            negativeStackValue = 0;
            for (int j = 0; j < dataSize; j++) {

                barSet = (BarSet) data.get(j);
                bar = (Bar) barSet.getEntry(i);

                if (bar.getValue() >= 0)
                    positiveStackValue += bar.getValue();
                else
                    negativeStackValue += bar.getValue();
            }

            if (maxStackValue < (int) Math.ceil(positiveStackValue))
                maxStackValue = (int) Math.ceil(positiveStackValue);
            if (minStackValue > (int) Math.ceil(negativeStackValue))
                minStackValue = (int) Math.ceil(negativeStackValue);
        }

        while (maxStackValue % this.getStep() != 0)
            maxStackValue += 1;
        while (minStackValue % this.getStep() != 0)
            minStackValue -= 1;

        super.setAxisBorderValues(minStackValue, maxStackValue, this.getStep());
    }



	/*
     * --------------------------------
	 * Overriden methods from ChartView
	 * --------------------------------
	 */

    @Override
    public ChartView setAxisBorderValues(int minValue, int maxValue, int step) {
        mCalcMaxValue = false;
        return super.setAxisBorderValues(minValue, maxValue, step);
    }


    @Override
    public void show() {

        if (mCalcMaxValue)
            calculateMaxStackBarValue();
        super.show();
    }

}