Android用RecyclerView实现动态添加本地图片

本文介绍了android用recyclerview实现动态添加本地图片，分享给大家，具体如下：

本文所用的多图选择的library来自：https://github.com/lovetuzitong/multiimageselector

简单介绍一下用法：

1、跳转到图片选择页面：

 intent intent = new intent(passengersetactivity.this, multiimageselectoractivity.class);
          intent.putextra(multiimageselectoractivity.extra_show_camera, true);
          intent.putextra(multiimageselectoractivity.extra_select_count, 9);
          intent.putextra(multiimageselectoractivity.extra_select_mode, multiimageselectoractivity.mode_single);
          startactivityforresult(intent, 10001);//10001-->添加

2、通过onactivityresult获取信息：

 final arraylist<string> paths = data.getstringarraylistextra(multiimageselectoractivity.extra_result);
 bitmap bitmap = bitmapfactory.decodefile(paths.get(0), diy_dialog.getbitmapoption(4));

首先设置布局管理器为：

recyclerview.setlayoutmanager(new gridlayoutmanager(this, 3));

然后设置适配器（这里在代码里面有详细的注释）：

public class passengeradapter extends recyclerview.adapter<passengeradapter.viewholder> {
  private context mcontext;
  private onitemclicklitener listener;//点击事件接口
  private arraylist<string> imageurls;
  private imagefetcher imagefetcher;
  private viewholder viewholder;
  private view view;

  /**
   * 在构造方法中传入图片地址的数据
   * @param context
   * @param imageurls
   */
  public passengeradapter(context context, arraylist<string> imageurls) {
    this.mcontext = context;
    this.imageurls = imageurls;
    //初始化加载网络图片的jar包
    imagefetcher = new imagefetcher(context);
    imagefetcher.setimagecache(imagecache.getinstance(context));
  }

  @override
  public viewholder oncreateviewholder(viewgroup parent, int viewtype) {
     view = layoutinflater.from(mcontext).inflate(r.layout.lay_passager, null);
     viewholder = new viewholder(view);
    return viewholder;
  }

  @override
  public void onbindviewholder(viewholder holder, int position) {
    //设置内容为“hehe”的的元素为默认的添加按钮
    if (imageurls.get(position).equals("hehe")) {
      holder.imageviewbig.setbackgroundresource(r.mipmap.add);
      //当图片是添加按钮的时候隐藏删除按钮
      holder.imageviewsmall.setvisibility(view.gone);
    } else {
      holder.imageviewsmall.setvisibility(view.visible);
      /**
       * 判断图片路径是网络地址还是本地图片
       * 设置路径之中包含“storage”的为本地图片
       */
      if (imageurls.get(position).contains("storage")) {
        try {
          file file = new file(imageurls.get(position));
          //将bitmap转化成drawable
          bitmap bmp = mediastore.images.media.getbitmap(mcontext.getcontentresolver(), uri.fromfile(file));
          drawable drawable =new bitmapdrawable(bmp);
          //按比例扩大图片的size居中显示，使得图片长(宽)等于或大于view的长(宽)
          holder.imageviewbig.setscaletype(imageview.scaletype.center_crop);
          holder.imageviewbig.setimagebitmap(bmp);
        } catch (ioexception e) {
          e.printstacktrace();
        }
//        holder.imageviewbig.setimageuri(uri.parse(imageurls.get(position)));
      } else {
        imagefetcher.loadimage(imageurls.get(position), holder.imageviewbig, r.mipmap.touxiang);
      }
    }
  }


  @override
  public int getitemcount() {
    return imageurls.size();
  }



  public void setonitemclicklitener(onitemclicklitener listener) {
    this.listener = listener;
  }

  public interface onitemclicklitener {
    void onbigclick(int position);

    void onsmallclick(int position);
  }
  class viewholder extends recyclerview.viewholder {
    imageview imageviewbig, imageviewsmall;

    public viewholder(view itemview) {
      super(itemview);
      imageviewbig = (imageview) itemview.findviewbyid(r.id.imageviewbig);
      imageviewsmall = (imageview) itemview.findviewbyid(r.id.imageviewsmall);
      /**
       *
       * 因为元素是变化的，动态的，所以对点击事件的处理放在viewholder类里面，调用getposition()
       * 可以获取到当前的元素位子
       */
      imageviewbig.setonclicklistener(new view.onclicklistener() {
        @override
        public void onclick(view v) {
          int position = (integer) v.gettag();
          listener.onbigclick(getposition());
        }
      });
      imageviewsmall.setonclicklistener(new view.onclicklistener() {
        @override
        public void onclick(view v) {
          int position = (integer) v.gettag();
          listener.onsmallclick(getposition());
        }
      });
    }
  }
}

recycler的布局文件

<?xml version="1.0" encoding="utf-8"?>
<framelayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  <framelayout
    android:id="@+id/lay_group"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <imageview
      android:id="@+id/imageviewbig"
      android:layout_width="120dp"
      android:layout_height="120dp"
      android:background="@mipmap/background"
      />
    <imageview
      android:id="@+id/imageviewsmall"
      android:layout_width="20dp"
      android:layout_height="20dp"
      android:background="@mipmap/del"
      android:layout_gravity="right"/>
  </framelayout>
</framelayout>

配置recyclerview和设置点击事件

recyclerview = (recyclerview) findviewbyid(r.id.recyclerview);
    recyclerview.setlayoutmanager(new gridlayoutmanager(this, 3));
    if(imageurls.size()==0){
      imageurls.add("hehe");
    }
    passengeradapter = new passengeradapter(this, imageurls);
    recyclerview.setadapter(passengeradapter);
    passengeradapter.setonitemclicklitener(new passengeradapter.onitemclicklitener() {
      @override
      public void onbigclick(int position) {
        log.d(tag, "onbigclick: "+passengeradapter.getitemcount());
        log.d(tag, "onbigclick: "+position);
        if (position==imageurls.size()-1) {
          //添加本地相册图片，更新视图
          intent intent = new intent(passengersetactivity.this, multiimageselectoractivity.class);
          intent.putextra(multiimageselectoractivity.extra_show_camera, true);
          intent.putextra(multiimageselectoractivity.extra_select_count, 9);
          intent.putextra(multiimageselectoractivity.extra_select_mode, multiimageselectoractivity.mode_single);
          startactivityforresult(intent, 10001);//10001-->添加
        } else {
          intent intent = new intent(passengersetactivity.this, multiimageselectoractivity.class);
          intent.putextra(multiimageselectoractivity.extra_show_camera, true);
          intent.putextra(multiimageselectoractivity.extra_select_count, 9);
          intent.putextra(multiimageselectoractivity.extra_select_mode, multiimageselectoractivity.mode_single);
          poss = position;
          startactivityforresult(intent, 10002);//10002-->修改
          //修改图片，更新视图
        }

      }
      @override
      public void onsmallclick(int position) {
        imageurls.remove(position);
        passengeradapter.notifyitemremoved(position);
        //删除图片，更新视图
      }
    });

选择完图片后，进行ui更新的操作

 /**
   * 返回图片url,并上传七牛
   *
   * @param requestcode
   * @param resultcode
   * @param data
   */
  @override
  protected void onactivityresult(int requestcode, int resultcode, intent data) {
    super.onactivityresult(requestcode, resultcode, data);
    if(data!=null){
      if (requestcode == 10001 || requestcode == 10002) {
        final arraylist<string> paths = data.getstringarraylistextra(multiimageselectoractivity.extra_result);
        bitmap bitmap = bitmapfactory.decodefile(paths.get(0), diy_dialog.getbitmapoption(4));
        //添加图片
        if (requestcode == 10001) {
          //将添加的图片放在第一位
          imageurls.add(0,paths.get(0));
          //更新第一个位置的图片
          passengeradapter.notifyiteminserted(0);
        }
        //修改图片
        else if (requestcode == 10002&&imageurls.size()>0) {
          int pos = poss;
          imageurls.set(pos,paths.get(0));
          passengeradapter.notifyitemchanged(pos);
        }

      }
    }

  }

大概就是这样了，简单的说一下思路，就是在存储图片的list的最后一项添加一个具有不同标识的数据，当点击时对应的标识和该标识一致，则添加，反之为修改。使用recylerview可以直接更新有变化的子项，而不用更新全部子项，用户体验更好，性能也提高了。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。