Android 任意View转为bitmap图片_imageview转化为bitmap

在开发的过程中有时会碰到这样的需求，把一个activity或者一个view变成图片分享出去。从网上收集了一些资料之后经过整理现在分享出来，教大家实现activity，scrollview，listview，recycleview，画中画以及在后台把layout生成图片的方法。如有侵权的地方，请及时告诉我改正，谢谢。

代码在这里 https://github.com/iotxc/ScreenShootDemo

在贴方法之前我要提醒大家注意一点，view中有图片的，如果是本地图片那么网上的代码你拿过来直接用就行了，如果是根据url加载的你要注意了，直接写Glide.with(this).load(url).into(imageview);你得到的将会是一片空白，要使用simpleTarget的回调加载图片才行

Glide.with(this)
          .load(url)
          .asBitmap()
          .into(new SimpleTarget<Bitmap>() {
           @Override
           public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {
                    imageview.setImageBitmap(resource);
 
                }
          }); 

具体是为什么我还不清楚。

screenshoot.gif

我也不知道视频为什么会这么模糊，凑合看一下吧= =，有知道怎么做的清晰点的请留言告诉我

1. activity截图

    /**
     * 获取指定Activity的截屏
     */
    public static Bitmap activityScreenShot(Activity activity) {
        // View是你需要截图的View
        View view = activity.getWindow().getDecorView();
        view.setDrawingCacheEnabled(true);
        view.buildDrawingCache();
        Bitmap bitmap = view.getDrawingCache();
 
        // 获取状态栏高度
        Rect frame = new Rect();
        activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
        int statusBarHeight = frame.top;
 
        // 获取屏幕长和高
        int width = activity.getWindowManager().getDefaultDisplay().getWidth();
        int height = activity.getWindowManager().getDefaultDisplay().getHeight();
 
        // 去掉标题栏
        Bitmap b = Bitmap.createBitmap(bitmap, 0, statusBarHeight, width, height - statusBarHeight);
        view.destroyDrawingCache();
 
        return b;
    }

2. scrollview截图
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

    /**
     * 获取scrollview的截屏
     */
    public static Bitmap scrollViewScreenShot(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截图
因为listview布局复用的问题并且只能绘制在屏幕上显示的ItemView，所以我们需要把它的item放到一个view的集合里最后通过拼接来完成整图的效果。但是当Item足够多的时候，肯定会发生oom的所以记得在获得bitmap之后对其进行压缩处理。

    /**
     * 获取listview的截屏
     * @param listview
     * @return
     */
    public static Bitmap shotListView(ListView listview) {
        ListAdapter adapter = listview.getAdapter();
        int itemscount = adapter.getCount();
        int allitemsheight = 0;
        List<Bitmap> bmps = new ArrayList<Bitmap>();
 
        //循环对listview的item进行截图， 最后拼接在一起
        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();
            //这里可以把listview中单独的item进行保存
//            viewSaveToImage(childView.getDrawingCache());
        }
        int w = listview.getMeasuredWidth();
        Bitmap bigbitmap = Bitmap.createBitmap(w, 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. recycleview截图
recycleview和listView使用相同的方案

   /**
     * recycleview截图
     * @param view
     * @return
     */
    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;
    }

5. 任意View转bitmap

    /**
     * view转bitmap
     */
   public Bitmap viewConversionBitmap(View v) {
        int w = v.getWidth();
        int h = v.getHeight();
 
        Bitmap bmp = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(bmp);
 
        c.drawColor(Color.WHITE);
        /** 如果不设置canvas画布为白色，则生成透明 */
 
        v.layout(0, 0, w, h);
        v.draw(c);
 
        return bmp;
    }

注意：这里的view只能是已经显示在界面上的，那没显示在界面上的怎么处理？往下看
此方法也是后台生成view的方法：

    /**
     * 计算view的大小
     */
  public void measureSize(Activity activity, String url) {
        //将布局转化成view对象
        View viewBitmap = LayoutInflater.from(activity).inflate(R.layout.background_layout, null);
 
        WindowManager manager = activity.getWindowManager();
        DisplayMetrics outMetrics = new DisplayMetrics();
        manager.getDefaultDisplay().getMetrics(outMetrics);
        int width = outMetrics.widthPixels;
        int height = outMetrics.heightPixels;
 
        //然后View和其内部的子View都具有了实际大小，也就是完成了布局，相当与添加到了界面上。接着就可以创建位图并在上面绘制了：
        layoutView(viewBitmap, width, height, url, activity);
    }
 
   /**
     * 填充布局内容 
     */
   public void layoutView(final View viewBitmap, int width, int height, String url, Activity activity) {
        // 整个View的大小 参数是左上角 和右下角的坐标
        viewBitmap.layout(0, 0, width, height);
        int measuredWidth = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY);
        int measuredHeight = View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.AT_MOST);
 
        viewBitmap.measure(measuredWidth, measuredHeight);
        viewBitmap.layout(0, 0, viewBitmap.getMeasuredWidth(), viewBitmap.getMeasuredHeight());
 
        TextView tv = viewBitmap.findViewById(R.id.tv_background);
        tv.setText("这是后台生成图片的标题");
 
        final ImageView imageView = viewBitmap.findViewById(R.id.iv_background);
 
        //注意加载网络图片时一定要用SimpleTarget回调
        Glide.with(activity).load(url).asBitmap().into(new SimpleTarget<Bitmap>() {
            @Override
            public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {
                imageView.setImageBitmap(resource);
                viewSaveToImage(viewBitmap);
            }
        });
    }
 
    /**
     * 把view转成图片
     * @param view
     */
   private void viewSaveToImage(View view) {
        view.setDrawingCacheEnabled(true);
        view.setDrawingCacheQuality(View.DRAWING_CACHE_QUALITY_HIGH);
        view.setDrawingCacheBackgroundColor(Color.WHITE);
 
        // 把一个View转换成图片
        Bitmap cachebmp = viewConversionBitmap(view);
 
        if (mBitmapDoneListener != null){
            mBitmapDoneListener.bitmapDone(cachebmp);
        }
 
        view.destroyDrawingCache();
    }

6. 圆角画中画

      /**
     * view转bitmap
     */
   public Bitmap viewConversionBitmap(View v) {
        int w = v.getWidth();
        int h = v.getHeight();
 
        Bitmap bmp = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(bmp);
 
        c.drawColor(Color.WHITE);
        /** 如果不设置canvas画布为白色，则生成透明 */
 
        v.layout(0, 0, w, h);
        v.draw(c);
 
        return bmp;
    }
 
    /**
     * 把上面获得的bitmap传进来就可以得到圆角的bitmap了
     */
    public void bitmapInBitmap(Bitmap bitmap, ImageView imageView) {
        Bitmap tempBitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);
        Canvas canvas = new Canvas(tempBitmap);
 
        //图像上画矩形
        Paint paint = new Paint();
        paint.setColor(Color.TRANSPARENT);
        paint.setStyle(Paint.Style.STROKE);//不填充
        paint.setStrokeWidth(10);  //线的宽度
        canvas.drawRect(10, 20, 100, 100, paint);
        imageView.setImageBitmap(tempBitmap);
 
        //画中画
        Paint photoPaint = new Paint(); // 建立画笔
        photoPaint.setDither(true); // 获取跟清晰的图像采样
        photoPaint.setFilterBitmap(true);// 过滤一些
 
        Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());// 创建一个指定的新矩形的坐标
        Rect dst = new Rect(0, 0, 300, 350);// 创建一个指定的新矩形的坐标
        canvas.drawBitmap(tempBitmap, src, dst, photoPaint);// 将photo 缩放或则扩大到
        imageView.setImageBitmap(getRoundedCornerBitmap(tempBitmap));
    }
 
    /**
     *   生成圆角图片
     */
    public Bitmap getRoundedCornerBitmap(Bitmap bitmap) {
        try {
            Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
                    bitmap.getHeight(), Bitmap.Config.ARGB_8888);
            Canvas canvas = new Canvas(output);
            final Paint paint = new Paint();
            final Rect rect = new Rect(0, 0, bitmap.getWidth(),
                    bitmap.getHeight());
            final RectF rectF = new RectF(new Rect(0, 0, bitmap.getWidth(),
                    bitmap.getHeight()));
            //设置圆角大小
            final float roundPx = 30;
            paint.setAntiAlias(true);
            canvas.drawARGB(0, 0, 0, 0);
            paint.setColor(Color.BLACK);
            canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
            paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
            final Rect src = new Rect(0, 0, bitmap.getWidth(),
                    bitmap.getHeight());
            canvas.drawBitmap(bitmap, src, rect, paint);
            return output;
        } catch (Exception e) {
            return bitmap;
        }
    }

以上就是所有的view转bitmap操作，得到bitmap之后你们就可以为所欲为了- -

再次提醒一下：加载网络图片要使用simpleTarget回调，直接加载得到的是一片空白，切记！！！
目前博主只试过glide一种图片框架，其他框架请自行试验

原文链接：https://www.jianshu.com/p/3d03c66cf169