如何在Android应用中实现一个图片添加功能

<?xml version="1.0" encoding="utf-8"?>



  
  

package com.dearxy.wxcircleaddpic;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import com.bumptech.glide.Glide;

import java.util.List;


/**
 * 展示上传的图片的GridView的适配器
 * 作者： 周旭 on 2017/6/21/0021.
 */

public class GridViewAdapter extends android.widget.BaseAdapter {

  private Context mContext;
  private List mList;
  private LayoutInflater inflater;

  public GridViewAdapter(Context mContext, List mList) {
    this.mContext = mContext;
    this.mList = mList;
    inflater = LayoutInflater.from(mContext);
  }

  @Override
  public int getCount() {
    //return mList.size() + 1;//因为最后多了一个添加图片的ImageView 
    int count = mList == null ? 1 : mList.size() + 1;
    if (count > MainConstant.MAX_SELECT_PIC_NUM) {
      return mList.size();
    } else {
      return count;
    }
  }

  @Override
  public Object getItem(int position) {
    return mList.get(position);
  }

  @Override
  public long getItemId(int position) {
    return position;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
    convertView = inflater.inflate(R.layout.grid_item, parent,false);
    ImageView iv = (ImageView) convertView.findViewById(R.id.pic_iv);
    if (position < mList.size()) {
     //代表+号之前的需要正常显示图片
      String picUrl = mList.get(position); //图片路径
      Glide.with(mContext).load(picUrl).into(iv);
    } else {
      iv.setImageResource(R.mipmap.zj);//最后一个显示加号图片 
    }
    return convertView;
  }
}

//初始化展示上传图片的GridView
  private void initGridView() {
    mPicList = new ArrayList<>();
    mGridViewAdapter = new GridViewAdapter(mContext, mPicList);
    gridView.setAdapter(mGridViewAdapter);
    gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
      @Override
      public void onItemClick(AdapterView<?> parent, View view,
                  int position, long id) {
        if (position == parent.getChildCount() - 1) {
          //添加凭证图片
          checkPhotoPermission();
        } else {
          //查看大图
          Intent intent = new Intent(mContext, PlusImageActivity.class);
          //图片的路径
          intent.putExtra(MainConstant.PIC_PATH, mPicList.get(position));
          intent.putExtra(MainConstant.POSITION, position);
          startActivityForResult(intent, MainConstant.REQUEST_CODE_MAIN);
        }
      }
    });
  }

 // 处理返回照片地址
  private void refreshAdapter(final ArrayList paths) {
    for (int i = 0; i < paths.size(); i++) {
      Log.i(TAG, "path:---->" + paths.get(i));
      proofPicCount++;
      if (proofPicCount <= MainConstant.MAX_SELECT_PIC_NUM) {
        //添加图片到GridView
        mPicList.add(paths.get(i));
      }
    }
    mGridViewAdapter.notifyDataSetChanged();
  }