Android 在图片的指定位置添加标记物

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  这些天,项目里加了一个功能效果,场景是: 假如有一个家居图片,图片里,有各样的家居用品: 桌子,毛巾,花瓶等等,需要在指定的商品处添加标记,方便用户直接看到商品,点击该标记,可以进入到商品详情页 。实现的效果图如下:


  要实现如上效果,有两个思路。

  思路1,通过addView,在容器(如FrameLayout)的特定位置,添加标记组件,同事在将ImageView页添加进容器中,保证容器的大小和ImageView的大小相同,这样可以确认标记点的位置不会出现错差。 

  思路2,通过绘制Bitmap,将背景图片和标记点绘制成同一张图片。

  比较两种方法,思路2有些不太妥的地方,1是不好实现标记图标的点击事件;2是不太容易扩展,比如标记点不仅仅是一个图片,而是一个弹框组件,有图有文。 所以,考虑再三后,决定选择第一种实现方式。

1. 自定义布局,包含放置标记图标的容器及显示底部图片的ImageView。




    

    


2. 自定义组件,便于添加标记图标、加载背景图
import android.content.Context;
import android.graphics.drawable.AnimationDrawable;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.Toast;

import com.bumptech.glide.Glide;
import com.lnyp.imgdots.R;
import com.lnyp.imgdots.bean.PointSimple;

import java.util.ArrayList;

public class ImageLayout extends FrameLayout implements View.OnClickListener {

    ArrayList points;

    FrameLayout layouPoints;

    ImageView imgBg;

    Context mContext;

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

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

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

        initView(context, attrs);
    }


    private void initView(Context context, AttributeSet attrs) {

        mContext = context;

        View imgPointLayout = inflate(context, R.layout.layout_imgview_point, this);

        imgBg = (ImageView) imgPointLayout.findViewById(R.id.imgBg);
        layouPoints = (FrameLayout) imgPointLayout.findViewById(R.id.layouPoints);
    }

    public void setImgBg(int width, int height, String imgUrl) {

        ViewGroup.LayoutParams lp = imgBg.getLayoutParams();
        lp.width = width;
        lp.height = height;

        imgBg.setLayoutParams(lp);

        ViewGroup.LayoutParams lp1 = layouPoints.getLayoutParams();
        lp1.width = width;
        lp1.height = height;

        layouPoints.setLayoutParams(lp1);

        Glide.with(mContext).load(imgUrl).asBitmap().into(imgBg);

        addPoints(width, height);

    }

    public void setPoints(ArrayList points) {

        this.points = points;
    }

    private void addPoints(int width, int height) {

        layouPoints.removeAllViews();

        for (int i = 0; i < points.size(); i++) {

            double width_scale = points.get(i).width_scale;
            double height_scale = points.get(i).height_scale;


            LinearLayout view = (LinearLayout) LayoutInflater.from(mContext).inflate(R.layout.layout_img_point, this, false);
            ImageView imageView = (ImageView) view.findViewById(R.id.imgPoint);
            imageView.setTag(i);

            AnimationDrawable animationDrawable = (AnimationDrawable) imageView.getDrawable();
            animationDrawable.start();

            LayoutParams layoutParams = (LayoutParams) view.getLayoutParams();

            layoutParams.leftMargin = (int) (width * width_scale);
            layoutParams.topMargin = (int) (height * height_scale);

            imageView.setOnClickListener(this);

            layouPoints.addView(view, layoutParams);
        }
    }


    @Override
    public void onClick(View view) {
        int pos = (int) view.getTag();
        Toast.makeText(getContext(), "pos : " + pos, Toast.LENGTH_SHORT).show();
    }
}
  来看看ImageLayout源码,里面有两个重要的方法:

·public void setImgBg(int width, int height, String imgUrl) 该方法主要根据图片的大小,设置标记图容器的大小,然后加载背景图。

·private void addPoints(int width, int height)  该方法主要向记图容器中添加标记图。

3.PointSimple.java

public class PointSimple {

    // 标记点相对于横向的宽度的比例
    public double width_scale;
    // 标记点相对于横向的高度的比例
    public double height_scale;

}
4. 添加背景图和标记图

 4.1 首先,准备一些测试数据

 private void initData() {

        imgSimples = new ArrayList<>();

        ImgSimple imgSimple1 = new ImgSimple();
        imgSimple1.url = "http://o79w6dswy.bkt.clouddn.com/img5.png";
        imgSimple1.scale = 1.6f;

        ArrayList pointSimples = new ArrayList<>();
        PointSimple pointSimple1 = new PointSimple();
        pointSimple1.width_scale = 0.36f;
        pointSimple1.height_scale = 0.75f;

        PointSimple pointSimple2 = new PointSimple();
        pointSimple2.width_scale = 0.64f;
        pointSimple2.height_scale = 0.5f;


        PointSimple pointSimple3 = new PointSimple();
        pointSimple3.width_scale = 0.276f;
        pointSimple3.height_scale = 0.764f;

        PointSimple pointSimple4 = new PointSimple();
        pointSimple4.width_scale = 0.638f;
        pointSimple4.height_scale = 0.74f;

        PointSimple pointSimple5 = new PointSimple();
        pointSimple5.width_scale = 0.796f;
        pointSimple5.height_scale = 0.526f;

        PointSimple pointSimple6 = new PointSimple();
        pointSimple6.width_scale = 0.486f;
        pointSimple6.height_scale = 0.364f;

        pointSimples.add(pointSimple1);
        pointSimples.add(pointSimple2);
        pointSimples.add(pointSimple3);
        pointSimples.add(pointSimple4);
        pointSimples.add(pointSimple5);
        pointSimples.add(pointSimple6);

        imgSimple1.pointSimples = pointSimples;


        ImgSimple imgSimple2 = new ImgSimple();
        imgSimple2.url = "http://o79w6dswy.bkt.clouddn.com/img3.png";
        imgSimple2.scale = 1.6f;

        ArrayList pointSimples2 = new ArrayList<>();
        PointSimple pointSimple7 = new PointSimple();
        pointSimple7.width_scale = 0.36f;
        pointSimple7.height_scale = 0.75f;

        PointSimple pointSimple8 = new PointSimple();
        pointSimple8.width_scale = 0.64f;
        pointSimple8.height_scale = 0.5f;


        PointSimple pointSimple9 = new PointSimple();
        pointSimple9.width_scale = 0.276f;
        pointSimple9.height_scale = 0.764f;


        pointSimples2.add(pointSimple7);
        pointSimples2.add(pointSimple8);
        pointSimples2.add(pointSimple9);

        imgSimple2.pointSimples = pointSimples2;


        ImgSimple imgSimple3 = new ImgSimple();
        imgSimple3.url = "http://o79w6dswy.bkt.clouddn.com/421428.jpg";
        imgSimple3.scale = 0.75f;

        ArrayList pointSimples3 = new ArrayList<>();
        PointSimple pointSimple11 = new PointSimple();
        pointSimple11.width_scale = 0.1f;
        pointSimple11.height_scale = 0.3f;

        PointSimple pointSimple12 = new PointSimple();
        pointSimple12.width_scale = 0.3f;
        pointSimple12.height_scale = 0.5f;


        PointSimple pointSimple13 = new PointSimple();
        pointSimple13.width_scale = 0.5f;
        pointSimple13.height_scale = 0.8f;


        pointSimples3.add(pointSimple11);
        pointSimples3.add(pointSimple12);
        pointSimples3.add(pointSimple13);

        imgSimple3.pointSimples = pointSimples3;

        imgSimples.add(imgSimple1);
        imgSimples.add(imgSimple2);
        imgSimples.add(imgSimple3);
    }

 4.2 加载图片和添加标记物,因为要做可以滑动展示的效果,所以在ViewPager的PagerAdapter中进行功能添加。
import android.app.Activity;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.DisplayMetrics;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;

import com.lnyp.imgdots.R;
import com.lnyp.imgdots.bean.ImgSimple;
import com.lnyp.imgdots.bean.PointSimple;
import com.lnyp.imgdots.view.ImageLayout;

import java.util.ArrayList;
import java.util.List;

public class ImgBrowsePagerAdapter extends PagerAdapter {

    List imgSimples;

    List views;

    Activity mContext;

    private int width;

    public ImgBrowsePagerAdapter(Activity context, List imgSimples) {

        this.mContext = context;
        this.imgSimples = imgSimples;

        this.views = new ArrayList<>();

        DisplayMetrics dm = new DisplayMetrics();
        context.getWindowManager().getDefaultDisplay().getMetrics(dm);

        width = dm.widthPixels;
    }

    @Override
    public int getCount() { // 获得size
        return imgSimples.size();
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
        return arg0 == arg1;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {

        ((ViewPager) container).removeView((View) object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {

        LinearLayout view = (LinearLayout) LayoutInflater.from(mContext).inflate(R.layout.layout_img_browse, null);
        ImageLayout layoutContent = (ImageLayout) view.findViewById(R.id.layoutContent);

        try {

            String imgUrl = imgSimples.get(position).url;
            float scale = imgSimples.get(position).scale;
            ArrayList pointSimples = imgSimples.get(position).pointSimples;

            layoutContent.setPoints(pointSimples);

            int height = (int) (width * scale);

            layoutContent.setImgBg(width, height, imgUrl);
        } catch (Exception e) {
            e.printStackTrace();
        }

        ((ViewPager) container).addView(view);

        return view;
    }
}
  4.3 适配器的布局文件layout_img_browse.xml,其中包含了上方自定义的组件ImageLayout



    

  此处,稍微讲下ImgBrowsePagerAdapter的instantiateItem(ViewGroup container, int position)方法,在该方法中,我们根据屏幕的宽度,对图片进行等比缩放,计算出了缩放后图片的大小(height和width), 该height和width也就是我们将要添加标记物所在的容器的大小。

  通过加载了布局文件,获取ImageLayout对象; 然后,有了这个对象,及计算出的height和width,我们就可以动态的添加背景图及标记物的位置。

  因为图片是经过等比缩放的,而标记物的位置是相对于图片的,所以在相同大小的容器添加标记物,它的位置不会出现偏差。

  通过以上几步,便可以实现前面动态图中的功能效果了。

  如有疑问或建议,欢迎进QQ群讨论:487786925( Android研发村 )

项目github地址:github.com/zuiwuyuan/I…