Android:放大版面并将其写入PDF会生成空白PDF [英] Android: inflating a layout and writting it to PDF produces a blank PDF

问题描述

当用户在活动中选择一个共享按钮时，我想填充一个布局，填充它，然后使用新的打印API将该布局写入pdf.

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.

我的片段中有

@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
        ...

很遗憾，这会输出空白的pdf文档.但是，当我使用屏幕上已经存在的视图(在onCreateView(..)中夸大)时，它按预期显示在pdf中.

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.

我将不胜感激.

推荐答案

如果我的理论是正确的-您的展开式布局的宽度和高度仍为零-您可以手动调用measure()和layout()大小和位置的东西:

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);

给出一个名为root的View，它将(及其子级，如果有的话)填充800像素宽，480像素高的空间(例如，WVGA设备，横向，全屏) .根据您的情况，您应该能够调用Canvas上的getWidth()和getHeight()来确定用于measure()和layout()的大小.

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，我个人会生成HTML并将其用作打印的基础，而不是布局文件.这是我在此示例项目中展示的技术之一.

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.

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