Android: inflating a layout and writting it to PDF produces a blank PDF

问题

when the user selects a share button within an activity, I would like to inflate a layout, populate it, and then write that layout to a pdf using the new printing API.

In my fragment I have

@TargetApi(Build.VERSION_CODES.KITKAT)
  public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
    switch (item.getItemId()) {
      case R.id.menu_item_share_context:
        LayoutInflator inflator = getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View container = inflator.inflate(R.layout.person_share, null, false);
        TextView name = (TextView)topContainer.findViewById(R.id.person_name);
        name.setText("Test Name");
        PdfDocument document = new PdfDocument();
        PdfDocument.PageInfo pageInfo = new PdfDocument.PageInfo.Builder(612, 792, 1).create()
        PdfDocument.Page page = document.startPage(pageInfo)
        container.draw(page.getCanvas());
        document.finishPage(page)

        // write pdf
        ...

This unfortunately outputs a blank pdf document. However, when I use a view that already exists on the screen (inflated in onCreateView(..)), it shows up in the pdf as expected.

I'd appreciate any help.

回答1:

If my theory is correct -- that your inflated layout still has a width and height of zero -- you can call measure() and layout() to manually size and position things:

root.measure(800, 480);
root.layout(0, 0, 800, 480);

Given a View named root, this will have it (and its children, if any) fill an 800-pixel wide by 480-pixel high space (e.g., a WVGA device, landscape, full-screen). In your case, you should be able to call getWidth() and getHeight() on the Canvas to determine the sizes to use for measure() and layout().

FWIW, personally, I'd generate HTML and use that for the basis of printing, rather than a layout file. That's one of the techniques I demonstrate in this sample project.

来源：https://stackoverflow.com/questions/25055685/android-inflating-a-layout-and-writting-it-to-pdf-produces-a-blank-pdf