如何将scrollview的整个内容转换为位图

Question

我正在尝试将ScrollView转换为Bitmap，但位图返回null。我不知道如何管理，请给我一个解决方案来实现这个目标 我想将整个ScrollView内容作为位图，以便之后创建PDF 遵循我的准则：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_first__resume__screen);
        Rlv = (RelativeLayout) findViewById(R.id.Rltv_Layout);
        Rlt_layoutWhole = (RelativeLayout) findViewById(R.id.Rlv_whole);
        Srvw = (ScrollView) findViewById(R.id.scrollView1);
        // View u = ((Activity) mContext).findViewById(R.id.scrollView1);
        Random rnd = new Random();
        int prevTextViewId = 0;
        RelativeLayout.LayoutParams params1 = new RelativeLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        for (int i = 0; i < 15; i++) {
            final TextView textView = new TextView(this);
            textView.setText("Text " + i);
            textView.setTextColor(rnd.nextInt() | 0xff000000);

            int curTextViewId = prevTextViewId + 1;
            textView.setId(curTextViewId);
            final RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(
                    RelativeLayout.LayoutParams.FILL_PARENT,
                    RelativeLayout.LayoutParams.WRAP_CONTENT);

            params.addRule(RelativeLayout.BELOW, prevTextViewId);
            params.setMargins(10, 0, 0, 0);
            textView.setLayoutParams(params);

            prevTextViewId = curTextViewId;
            Rlv.addView(textView, params);
        }

//      Rlt_layoutWhole.setDrawingCacheEnabled(true);
//      Rlt_layoutWhole.buildDrawingCache();
//      Bitmap bm = Rlt_layoutWhole.getDrawingCache();
        Rlt_layoutWhole.setDrawingCacheEnabled(true);
        Rlt_layoutWhole.refreshDrawableState();
          Bitmap bitmap = Rlt_layoutWhole.getDrawingCache();
          Rlt_layoutWhole.setDrawingCacheEnabled(false);

//      Bitmap bitmap = Bitmap.createBitmap(Rlt_layoutWhole.getWidth(),
//              Rlt_layoutWhole.getHeight(), Bitmap.Config.ARGB_8888);
//      Canvas canvas = new Canvas(bitmap);
//      Rlt_layoutWhole.draw(canvas);
//      createPDF(bitmap);
//  
        //****************************************************************88
//      int totalHeight = Srvw.getChildAt(0).getHeight();
//      int totalWidth = Srvw.getChildAt(0).getWidth();
//
//      Bitmap b = getBitmapFromView(Srvw,1200,300);             
//
//      //Save bitmap
//      String extr = Environment.getExternalStorageDirectory()+"/Folder/";
//      String fileName = "report.jpg";
//      File myPath = new File(extr, fileName);
//      FileOutputStream fos = null;
//      try {
//          fos = new FileOutputStream(myPath);
//          b.compress(Bitmap.CompressFormat.JPEG, 100, fos);
//          fos.flush();
//          fos.close();
//          MediaStore.Images.Media.insertImage(mContext.getContentResolver(), b, "Screen", "screen");
//      }catch (FileNotFoundException e) {
//          // TODO Auto-generated catch block
//          e.printStackTrace();
//      } catch (Exception e) {
//          // TODO Auto-generated catch block
//          e.printStackTrace();
//      }
        //********************************************************************************************8
         int height = Math.min(500, 500);
         //  float percent = height / (float)totalHeight;

           Bitmap canvasBitmap = Bitmap.createBitmap((int)(1500),(int)(1500), Bitmap.Config.ARGB_8888);
           Canvas canvas = new Canvas(canvasBitmap);

           Drawable bgDrawable = Srvw.getBackground();
           if (bgDrawable != null)
              bgDrawable.draw(canvas);
           else
              canvas.drawColor(Color.BLACK);

           canvas.save();
           //canvas.scale(100, percent);
           Srvw.draw(canvas);
           canvas.restore();

        createPDF(canvasBitmap);

    }

    public Bitmap getBitmapFromView(View view, int totalHeight, int totalWidth) {

        Bitmap returnedBitmap = Bitmap.createBitmap(totalWidth,totalHeight , Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(returnedBitmap);
        Drawable bgDrawable = view.getBackground();
        if (bgDrawable != null)
            bgDrawable.draw(canvas);
        else
            canvas.drawColor(Color.WHITE);
        view.draw(canvas);
        return returnedBitmap;
    }



    public Bitmap getBitmapFromView(View view) {
        view.setDrawingCacheEnabled(true);
        view.refreshDrawableState();
        Bitmap bitmap = view.getDrawingCache();
        view.setDrawingCacheEnabled(false);
        return bitmap;
    }