安卓实现随Viewpager滑动而滑动的指示器小圆点

此前在网上看到好多大神写的指示器，也有带平移效果的，但是都不是怎么满意，菜鸟的我今天在这里贡献一下利用shape和自定义View实现的Viewpager指示器，并且还可以多种自定义样式哦，欢迎大家共同来探讨和评论，代码还有很多优化及修改的地方欢迎大家发表意见
下面展示一下效果：

有需要的小伙伴可以在下方留言这里将发送demo，近期可能会更新上码云，需要码云链接的可以在下方评论，话不多说下面展示核心代码

自定义控件类

package com.example.administrator.slidingindicator;

import android.content.Context;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.GradientDrawable;
import android.support.annotation.DrawableRes;
import android.support.v4.content.ContextCompat;
import android.util.AttributeSet;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.HorizontalScrollView;
import android.widget.ImageView;
import android.widget.LinearLayout;

public class SlidingIndicator extends HorizontalScrollView {
    private int mNumber = 1;
    private Context mContext;
    private LinearLayout mLinearLayout;
    private FrameLayout mFrameLayout;
    private ImageView imageView;
    float leftMargin = 0;
    private int ivWidth = 40;
    private int ivHeight = 20;
    private int dotBgId = R.drawable.ease_btn_blue_normal_shape;
    private int ivBgid = R.drawable.shape_iv_view_bg;

public SlidingIndicator(Context context) {
    this(context,null);
}

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

public SlidingIndicator(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    mContext = context;

}

/**
 * 设置指示器点的个数
 * @param number
 */
public void setNumber(int number){
    if(number > 0){
        mNumber = number;
    }

}

/**
 * 设置指示器滚动条宽度
 * @param width
 */
public void setIvWidth(int width) {
    if(width>0&& width<=100) {
        this.ivWidth = width;
    }
}

/**
 * 设置指示器滚动条高度
 * @param height
 */
public void setIvHeight(int height) {
    if(height>0 && height<=100) {
        this.ivHeight = height;
    }
}

/**
 * 展示指示器
 */
public void slidingIndicatorShow(){
    init(mContext,ivWidth,ivHeight);
}

/**
 * 设置底部小点背景图片或颜色
 * @param drawableId
 */
public void setDotBg(@DrawableRes int drawableId){
   dotBgId = drawableId;
}


/**
 * 设置滑动滚动条背景
 * @param drawableId
 */
public void setIvSlidingBg(@DrawableRes int drawableId){
    ivBgid = drawableId;
}

private void init(Context context, int width, int height) {
    mFrameLayout = new FrameLayout(context);
    mFrameLayout.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
    mLinearLayout = new LinearLayout(context);
    mLinearLayout.setOrientation(LinearLayout.HORIZONTAL);
    mLinearLayout.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
    imageView = new ImageView(context);
    MarginLayoutParams vmi = new MarginLayoutParams(width,height);
    imageView.setLayoutParams(vmi);
    imageView.setBackgroundResource(ivBgid);
    for (int i = 0 ;i 0 && positionOffset <= 0.5) {
        viewWidth = (int) (viewWidth * (1 - positionOffset));
        leftMargin = ((ivWidth + viewWidth) * positionOffset) + (ivWidth * position);

    } else if (positionOffset > 0.5 && positionOffset <= 1) {
        viewWidth = (int) (ivWidth * positionOffset);
        leftMargin = ((ivWidth + ivWidth - viewWidth) * positionOffset) + (ivWidth * position);
    }
    ViewGroup.MarginLayoutParams params = (ViewGroup.MarginLayoutParams) imageView.getLayoutParams();
    params.width = viewWidth;
    params.leftMargin = Math.round(leftMargin);
    imageView.setLayoutParams(params);
}


}

ease_btn_blue_normal_shape.xml

shape_iv_view_bg.xml

在activity或者其他布局中使用方式对齐方式等自己设置

代码中先通过findviewbyid获取Viewpager对象和SlidingIndicator对象
这里就不展示代码了
这里是slidingIndicator的一些设置方法，具体可查看该控件提供的方法
slidingIndicator.setNumber(数量);
展示指示器（必须调用）
slidingIndicator.slidingIndicatorShow();
然后监听Viewpager滑动事件

mVpDot.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            	//通过该方法设置slidingIndicator的滑动及变形事件
                slidingIndicator.setViewLayoutParams(position,positionOffset);
             }

            @Override
            public void onPageSelected(int position) {

            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });