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我们。