用RecyclerView实现动态添加本地图片

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。
好了，今天就这样了。
—2016-07-15