com.blogspot.ksoichiro.viewIndicator.ViewIndicator.java Source code

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Here is the source code for com.blogspot.ksoichiro.viewIndicator.ViewIndicator.java

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/*
 * Copyright (c) 2012 Soichiro Kashima
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.blogspot.ksoichiro.viewIndicator;

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.View;

/**
 * View which has circle-formed page indicator.
 * 
 * @author ksoichiro
 */
public class ViewIndicator extends View {

    private static final float RADIUS = 5.0f;
    private static final float DISTANCE = 30.0f;

    private int mNumOfViews;
    private int mPosition;
    private ViewPager mViewPager;

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

    /**
     * @param context 
     * @param attrs 
     * @param defStyle 
     */
    public ViewIndicator(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    /**
     * @param context 
     * @param attrs 
     */
    public ViewIndicator(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    /** 
     * @param position 
     * */
    public void setPosition(final int position) {
        if (position < mNumOfViews) {
            mPosition = position;
            if (mViewPager != null) {
                mViewPager.setCurrentItem(mPosition);
            }
            invalidate();
        }
    }

    /** 
     * @param viewPager 
     * */
    public void setViewPager(final ViewPager viewPager) {
        mViewPager = viewPager;
        updateNumOfViews();
        mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrollStateChanged(int state) {
            }

            /** 
             * @param position 
             * @param positionOffest 
             * @param positionOffestPixels 
             * */
            @Override
            public void onPageScrolled(int position, float positionOffest, int positionOffestPixels) {
            }

            @Override
            public void onPageSelected(int position) {
                updateNumOfViews();
                setPosition(position);
            }
        });
    }

    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        Paint paint = new Paint();
        paint.setStrokeWidth(1);
        paint.setStrokeCap(Paint.Cap.ROUND);
        paint.setColor(Color.BLACK);
        paint.setAntiAlias(true);

        for (int i = 0; i < mNumOfViews; i++) {
            float cx = (getWidth() - (mNumOfViews - 1) * DISTANCE) / 2 + i * DISTANCE;
            float cy = getHeight() / 2.0f;
            if (mPosition == i) {
                paint.setStyle(Paint.Style.FILL_AND_STROKE);
            } else {
                paint.setStyle(Paint.Style.STROKE);
            }
            canvas.drawCircle(cx, cy, RADIUS, paint);
        }
    }

    private void updateNumOfViews() {
        if (mViewPager.getAdapter() == null) {
            mNumOfViews = 0;
        } else {
            mNumOfViews = mViewPager.getAdapter().getCount();
        }
    }

}