Android 多种截屏方式介绍

做项目的时候遇到截图的功能要求（部分截图、截长图），感觉挺有意思的，所有下来查阅了下资料，学习了下原理。在此记录下，供大家参考

效果图：

原理：计算好图片的宽度与高度，通过Bitmap 于Canvas 绘制好即可，不同之处是获取宽高方式不同。

关键代码如下：

整个屏幕截屏（不包含状态栏）

    public Bitmap screenShot() {
        View view = getWindow().getDecorView();
        view.setDrawingCacheEnabled(true);
        view.buildDrawingCache();

        return Bitmap.createBitmap(view.getDrawingCache());
    }

整个屏幕截屏（包含状态栏） 调用系统录屏、截屏功能

控件截屏

    private Bitmap viewShot(LinearLayout linearLayout) {
        int h = 0;
        Bitmap bitmap;
        for (int i = 0; i < linearLayout.getChildCount(); i++) {
            h += linearLayout.getChildAt(i).getHeight();
        }
        bitmap = Bitmap.createBitmap(linearLayout.getWidth(), h, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        linearLayout.draw(canvas);
        return bitmap;
    }

滚动截屏

  private Bitmap scrollershot(ScrollView scrollView) {
        int h = 0;
        Bitmap bitmap;

        //计算总高度
        for (int i = 0; i < scrollView.getChildCount(); i++) {
            h += scrollView.getChildAt(i).getHeight();
        }
        //创建bitmap
        bitmap = Bitmap.createBitmap(scrollView.getWidth(), h, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        scrollView.draw(canvas);
        return bitmap;
    }

列表截屏

ListView

    public 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;
    }

RecyclerView

    public 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;
    }

webView截屏

    private Bitmap webViewShot(WebView webView) {
        Picture picture = webView.capturePicture();
        Bitmap bitmap = Bitmap.createBitmap(picture.getWidth(), picture.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        picture.draw(canvas);
        return bitmap;
    }