Android生成view分享截图

Posted 2021-07-03 亮亮在江湖

                                                                         原生view截图        

                                                                     合并后的view截图

主要的业务逻辑，点击界面时有一个缩放动画，对当前界面进行截屏，启用DrawingCache并创建位图，将view界面转化为bitmap，进行保存下来。然后隐藏掉原界面，显示合成后的界面。
主要代码：

                setAnimator(1f, 0.8f);
                //对当前页面进行截屏
                source.setDrawingCacheEnabled(true);
                source.buildDrawingCache();  //启用DrawingCache并创建位图
                //创建一个DrawingCache的拷贝，因为DrawingCache得到的位图在禁用后会被回收
                Bitmap screen = Bitmap.createBitmap(createViewBitmap(source));
                sourceMid.setImageBitmap(screen);
                source.setVisibility(View.GONE);
                splicing.setVisibility(View.VISIBLE);
                splicing.post(new Runnable() {
                    @Override
                    public void run() {
                        screenBitmap = Bitmap.createBitmap(createViewBitmap(splicing)); //合成后的图片
                        initDownloadImg();
                    }
                });

private void initDownloadImg() {
        File savedir = new File(FILE_SAVEPATH);
        if (!savedir.exists()) {
            savedir.mkdirs();
        }

        FileOutputStream out = null;
        try {
            out = new FileOutputStream(pathfile);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            Toast.makeText(this,"保存失败",Toast.LENGTH_SHORT).show();
        }
        try {
            if (null != out) {
                screenBitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
                out.flush();
                out.close();
            }
            Toast.makeText(this,"保存成功",Toast.LENGTH_SHORT).show();
            sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(new File(pathfile))));
        } catch (IOException e) {
            Toast.makeText(this,"保存失败",Toast.LENGTH_SHORT).show();
        }
    }

    public Bitmap createViewBitmap(View v) {
        Bitmap bitmap = Bitmap.createBitmap(v.getWidth(), v.getHeight(),
                Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        v.draw(canvas);
        return bitmap;
    }

具体demo资源下载路径：view合并分享截图

接下来涉及些其他截屏的方案，包含普通截屏，Scrollview截屏，listview截屏，RecyclerView截屏，合成Bitmap。

1、普通截屏的实现
获取当前Window的DrawingCache的方式，即decorView的DrawingCache

/**
   * shot the current screen ,with the status but the status is trans *
   *
   * @param ctx current activity
   */
  public static Bitmap shotActivity(Activity ctx) {

    View view = ctx.getWindow().getDecorView();
    view.setDrawingCacheEnabled(true);
    view.buildDrawingCache();

    Bitmap bp = Bitmap.createBitmap(view.getDrawingCache(), 0, 0, view.getMeasuredWidth(),
        view.getMeasuredHeight());

    view.setDrawingCacheEnabled(false);
    view.destroyDrawingCache();

    return bp;
  }

获取当前View的DrawingCache

public static Bitmap getViewBp(View v) {
        if (null == v) {
            return null;
        }
        v.setDrawingCacheEnabled(true);
        v.buildDrawingCache();
        if (Build.VERSION.SDK_INT >= 11) {
            v.measure(MeasureSpec.makeMeasureSpec(v.getWidth(),
                    MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(
                    v.getHeight(), MeasureSpec.EXACTLY));
            v.layout((int) v.getX(), (int) v.getY(),
                    (int) v.getX() + v.getMeasuredWidth(),
                    (int) v.getY() + v.getMeasuredHeight());
        } else {
            v.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
                    MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
            v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
        }
        Bitmap b = Bitmap.createBitmap(v.getDrawingCache(), 0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());

        v.setDrawingCacheEnabled(false);
        v.destroyDrawingCache();
        return b;
    }

2、Scrollview截屏

三个截屏中，ScrollView最简单，因为ScrollView只有一个childView，虽然没有全部显示在界面上，但是已经全部渲染绘制，因此可以直接 调用scrollView.draw(canvas)来完成截图

public static Bitmap shotScrollView(ScrollView scrollView) {
    int h = 0;
    Bitmap bitmap = null;
    for (int i = 0; i < scrollView.getChildCount(); i++) {
      h += scrollView.getChildAt(i).getHeight();
      scrollView.getChildAt(i).setBackgroundColor(Color.parseColor("#ffffff"));
    }
    bitmap = Bitmap.createBitmap(scrollView.getWidth(), h, Bitmap.Config.RGB_565);
    final Canvas canvas = new Canvas(bitmap);
    scrollView.draw(canvas);
    return bitmap;
  }

3、listview截屏

而ListView就是会回收与重用Item，并且只会绘制在屏幕上显示的ItemView，根据stackoverflow上大神的建议，采用一个List来存储Item的视图，这种方案依然不够好，当Item足够多的时候，可能会发生oom。

  public static Bitmap shotListView(ListView listview) {

    ListAdapter adapter = listview.getAdapter();
    int itemscount = adapter.getCount();
    int allitemsheight = 0;
    List<Bitmap> bmps = new ArrayList<Bitmap>();

    for (int i = 0; i < itemscount; i++) {

      View childView = adapter.getView(i, null, listview);
      childView.measure(
          View.MeasureSpec.makeMeasureSpec(listview.getWidth(), View.MeasureSpec.EXACTLY),
          View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));

      childView.layout(0, 0, childView.getMeasuredWidth(), childView.getMeasuredHeight());
      childView.setDrawingCacheEnabled(true);
      childView.buildDrawingCache();
      bmps.add(childView.getDrawingCache());
      allitemsheight += childView.getMeasuredHeight();
    }

    Bitmap bigbitmap =
        Bitmap.createBitmap(listview.getMeasuredWidth(), allitemsheight, Bitmap.Config.ARGB_8888);
    Canvas bigcanvas = new Canvas(bigbitmap);

    Paint paint = new Paint();
    int iHeight = 0;

    for (int i = 0; i < bmps.size(); i++) {
      Bitmap bmp = bmps.get(i);
      bigcanvas.drawBitmap(bmp, 0, iHeight, paint);
      iHeight += bmp.getHeight();

      bmp.recycle();
      bmp = null;
    }

    return bigbitmap;
  }

4、RecyclerView截屏

我们都知道，在新的android版本中，已经可以用RecyclerView来代替使用ListView的场景，相比较ListView，RecyclerView对Item View的缓存支持的更好。可以采用和ListView相同的方案，这里也是在stackoverflow上看到的方案。

  public static Bitmap shotRecyclerView(RecyclerView view) {
    RecyclerView.Adapter adapter = view.getAdapter();
    Bitmap bigBitmap = null;
    if (adapter != null) {
      int size = adapter.getItemCount();
      int height = 0;
      Paint paint = new Paint();
      int iHeight = 0;
      final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);

      // Use 1/8th of the available memory for this memory cache.
      final int cacheSize = maxMemory / 8;
      LruCache<String, Bitmap> bitmaCache = new LruCache<>(cacheSize);
      for (int i = 0; i < size; i++) {
        RecyclerView.ViewHolder holder = adapter.createViewHolder(view, adapter.getItemViewType(i));
        adapter.onBindViewHolder(holder, i);
        holder.itemView.measure(
            View.MeasureSpec.makeMeasureSpec(view.getWidth(), View.MeasureSpec.EXACTLY),
            View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
        holder.itemView.layout(0, 0, holder.itemView.getMeasuredWidth(),
            holder.itemView.getMeasuredHeight());
        holder.itemView.setDrawingCacheEnabled(true);
        holder.itemView.buildDrawingCache();
        Bitmap drawingCache = holder.itemView.getDrawingCache();
        if (drawingCache != null) {

          bitmaCache.put(String.valueOf(i), drawingCache);
        }
        height += holder.itemView.getMeasuredHeight();
      }

      bigBitmap = Bitmap.createBitmap(view.getMeasuredWidth(), height, Bitmap.Config.ARGB_8888);
      Canvas bigCanvas = new Canvas(bigBitmap);
      Drawable lBackground = view.getBackground();
      if (lBackground instanceof ColorDrawable) {
        ColorDrawable lColorDrawable = (ColorDrawable) lBackground;
        int lColor = lColorDrawable.getColor();
        bigCanvas.drawColor(lColor);
      }

      for (int i = 0; i < size; i++) {
        Bitmap bitmap = bitmaCache.get(String.valueOf(i));
        bigCanvas.drawBitmap(bitmap, 0f, iHeight, paint);
        iHeight += bitmap.getHeight();
        bitmap.recycle();
      }
    }
    return bigBitmap;
  }

相信有不少小伙伴用BRVH第三方库来做recycleview的适配器的。使用这个库的话再用上面的方法会报角标越界的错误，看了BRVH的源码

 public void onBindViewHolder(ViewHolder holder, int positions) {
        int viewType = holder.getItemViewType();
        switch(viewType) {
        case 0:
            this.convert((BaseViewHolder)holder, this.mData.get(holder.getLayoutPosition() - this.getHeaderLayoutCount()));
        case 273:
        case 819:
        case 1365:
            break;
        case 546:
            this.addLoadMore(holder);
            break;
        default:
            this.convert((BaseViewHolder)holder, this.mData.get(holder.getLayoutPosition() - this.getHeaderLayoutCount()));
            this.onBindDefViewHolder((BaseViewHolder)holder, this.mData.get(holder.getLayoutPosition() - this.getHeaderLayoutCount()));
        }

    }

在调用adapter.onBindViewHolder时，因为里面的position参数未使用，里面用的计算holder.getLayoutPosition() - this.getHeaderLayoutCount()的值一直是-1导致角标越界报错。

本人理解，RecyclerView的截屏原理是，首先构造每个item的ViewHolder，然后调用具体设置数据到每个item的方法，此时cache中就存有item的内容，此时绘制就能获取到完整的内容。采用v7包中的onBindViewHolder方法即可，或者是BRVH的convert方法，可以看到BRVH中没有暴露出这个方法，而且唯一暴露出的onBindViewHolder还会报角标越界错误，此时我们就需要在BRVH的基础上暴露出convert即可，代码如下

 public class MyAdapter extends BaseQuickAdapter<T> {

        public MyAdapter() {
            super(getItemLayoutResId(), datas);
        }

        /**
         * 用于对外暴露convert方法,构造缓存视图(截屏用)
         * @param viewHolder
         * @param t
         */
        public void startConvert(BaseViewHolder viewHolder, T t){
            convert(viewHolder,t);
        }

        @Override
        protected void convert(BaseViewHolder viewHolder, T t) {
            bindView(viewHolder, t);
        }
    }

然后将上面所述的获取Bitmap方法修改一下

 /**
     * 截取recycler view
     */
    public static Bitmap getRecyclerViewScreenshot(RecyclerView view) {
        BaseListFragment.MyAdapter adapter = (BaseListFragment.MyAdapter) view.getAdapter();
        Bitmap bigBitmap = null;
        if (adapter != null) {
            int size = adapter.getData().size();
            int height = 0;
            Paint paint = new Paint();
            int iHeight = 0;
            final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);

            // Use 1/8th of the available memory for this memory cache.
            final int cacheSize = maxMemory / 8;
            LruCache<String, Bitmap> bitmaCache = new LruCache<>(cacheSize);
            for (int i = 0; i < size; i++) {
                BaseViewHolder holder = (BaseViewHolder) adapter.createViewHolder(view, adapter.getItemViewType(i));
                //此处需要调用convert方法，否则绘制出来的都是空的item
                adapter.startConvert(holder, adapter.getData().get(i));
                holder.itemView.measure(
                        View.MeasureSpec.makeMeasureSpec(view.getWidth(), View.MeasureSpec.EXACTLY),
                        View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
                holder.itemView.layout(0, 0, holder.itemView.getMeasuredWidth(),
                        holder.itemView.getMeasuredHeight());
                holder.itemView.setDrawingCacheEnabled(true);
                holder.itemView.buildDrawingCache();
                Bitmap drawingCache = holder.itemView.getDrawingCache();
                if (drawingCache != null) {

                    bitmaCache.put(String.valueOf(i), drawingCache);
                }
                height += holder.itemView.getMeasuredHeight();
            }

            bigBitmap = Bitmap.createBitmap(view.getMeasuredWidth(), height, Bitmap.Config.ARGB_8888);
            Canvas bigCanvas = new Canvas(bigBitmap);
            Drawable lBackground = view.getBackground();
            if (lBackground instanceof ColorDrawable) {
                ColorDrawable lColorDrawable = (ColorDrawable) lBackground;
                int lColor = lColorDrawable.getColor();
                bigCanvas.drawColor(lColor);
            }

            for (int i = 0; i < size; i++) {
                Bitmap bitmap = bitmaCache.get(String.valueOf(i));
                bigCanvas.drawBitmap(bitmap, 0f, iHeight, paint);
                iHeight += bitmap.getHeight();
                bitmap.recycle();
            }
        }
        return bigBitmap;
    }

5、合成Bitmap

比如四张合成一张

  /**
     * 将四张图拼成一张
     *
     * @param pic1 图一
     * @param pic2 图二
     * @param pic3 图三
     * @param pic4 图四
     * @return only_bitmap
     * 详情见说明：{@link com.bertadata.qxb.util.ScreenShotUtils}
     */
    public static Bitmap combineBitmapsIntoOnlyOne(Bitmap pic1, Bitmap pic2, Bitmap pic3, Bitmap pic4, Activity context) {
        int w_total = pic2.getWidth();
        int h_total = pic1.getHeight() + pic2.getHeight() + pic3.getHeight() + pic4.getHeight();
        int h_pic1 = pic1.getHeight();
        int h_pic4 = pic4.getHeight();
        int h_pic12 = pic1.getHeight() + pic2.getHeight();
        //此处为防止OOM需要对高度做限制
        if (h_total > HEIGHTLIMIT) {
            return null;
        }

        Bitmap only_bitmap = Bitmap.createBitmap(w_total, h_total, Bitmap.Config.ARGB_4444);
        Canvas canvas = new Canvas(only_bitmap);
        canvas.drawColor(ContextCompat.getColor(context, R.color.color_content_bg));
        canvas.drawBitmap(pic1, 0, 0, null);
        canvas.drawBitmap(pic2, 0, h_pic1, null);
        canvas.drawBitmap(pic3, 0, h_pic12, null);
        canvas.drawBitmap(pic4, 0, h_total - h_pic4, null);
        return only_bitmap;
    }