在Android中将Listview转换为pdf [英] Listview to pdf in android

问题描述

我有一个自定义列表视图，我想从整个列表视图制作pdf.我引用了很多帖子，并在下面的代码中实现了这些代码，这些代码将我的 listview转换为pdf .但是问题是它没有包含整个listview项. pdf中仅提供前几项.

I have a custom listview and I want to make pdf from the whole listview. I refered many posts and implemented below code which converts my listview to pdf. But problem is its not containing the whole listview item. Only first few items are available in the pdf.

我将 listview转换为pdf 的功能是

fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            String state = Environment.getExternalStorageState();
            if (!Environment.MEDIA_MOUNTED.equals(state)) {

            }
            File pdfDir = new File(Environment.getExternalStoragePublicDirectory(
                    Environment.DIRECTORY_DOCUMENTS), "MyProject");
            if (!pdfDir.exists()){
                pdfDir.mkdir();
            }
            Bitmap screen =  getWholeListViewItemsToBitmap();
            File pdfFile = new File(pdfDir, "myPdfFile_new.pdf");

            try {
                Document document = new Document();
                PdfWriter.getInstance(document, new FileOutputStream(pdfFile));
                document.open();
                ByteArrayOutputStream stream = new ByteArrayOutputStream();
                screen.compress(Bitmap.CompressFormat.PNG, 100, stream);
                byte[] byteArray = stream.toByteArray();
                addImage(document,byteArray);
                document.close();
            }
            catch (Exception e){
                e.printStackTrace();
            }
        }
    });

addImage方法

addImage method

private static void addImage(Document document,byte[] byteArray)
{
    Image image = null;
    try
    {
        image = Image.getInstance(byteArray);
    }
    catch (BadElementException e)
    {
        e.printStackTrace();
    }
    catch (MalformedURLException e)
    {
        e.printStackTrace();
    }
    catch (IOException e)
    {
        e.printStackTrace();
    }
    try
    {
        document.add(image);
    } catch (DocumentException e) {
        e.printStackTrace();
    }
}

获取列表项的方法

public Bitmap getWholeListViewItemsToBitmap() {

    ListView listview    = StockReportActivity.category_list;
    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;
    }

我的列表视图中包含大量项目，因此如何将整个列表视图转换为pdf.感谢您的所有建议

My listview contains large number of items in it, so how can i convert the whole listview to pdf. All your suggestions are appreciated

推荐答案

您可以在recyclerView中获取屏幕上显示的项目数，因此为第一组视图创建位图，然后可以动态滚动至以下项目最后显示的项目(即noOfItemDisplayed + 1)，再次获取位图，同样将所有位图都获取到ArrayList<Bitmap>中，您可以从中创建pdf文件，请参考下面的代码从位图的数组列表中创建pdf:

You can get the number of items displayed on screen in recyclerView, so create bitmap for first set of views, after that you can dynamically scroll to item below the last item displayed (i.e noOfItemDisplayed+1), again get bitmap, likewise all get all bitmaps into ArrayList<Bitmap> from which you can create pdf file, refer to code below to create pdf from arraylist of bitmaps:

@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
private void createPdf() throws IOException {

    PdfDocument document = new PdfDocument();
    PdfDocument.Page page = null;
    // crate a page description
    for (int i = 0; i < bitmaps.size(); i++) {
        Bitmap bitmap = bitmaps.get(i);
        PdfDocument.PageInfo pageInfo = new PdfDocument.PageInfo.Builder(1400, 1979, i).create();

        // start a page
        page = document.startPage(pageInfo);
        if (page == null) {
            return;
        }
        Canvas canvas = page.getCanvas();
        canvas.drawBitmap(bitmap, 0, 0, null);
        document.finishPage(page);
    }

    // finish the page


    // write the document content
    fileHandler = new FileHandler(this, getString(R.string.app_name));
    File pdf = fileHandler.getNewFileToWrite(AppConstants.FileExtensions.PDF); //crete and get file

    try {
        document.writeTo(new FileOutputStream(pdf));
    } catch (IOException e) {
        logger.error(e);
    }

    // close the document
    document.close();

}

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