Question

        PdfDocument document = new PdfDocument();
        // crate a page description
        PageInfo pageInfo = new PageInfo.Builder(300, 300, 1).create();
        // create a new page from the PageInfo
        Page page = document.startPage(pageInfo);
        // repaint the user's text into the page
        View content = findViewById(R.id.textarea);
        content.draw(page.getCanvas());
        // do final processing of the page
        document.finishPage(page);
        try {
             File f = getPDFPath();
             FileOutputStream fos = new FileOutputStream(f);
             document.writeTo(fos);
             document.close();
             fos.close();

        } catch (IOException e) {
            throw new RuntimeException("Error generating file", e);
        }

findViewById(R.id.textarea);引用带有某些文字的TextView，但上面的代码只生成空pdf。可能是什么问题？

是否有任何链接有使用Android原生API生成pdf的工作样本？

Answer 1

我有，但经过大量测试后，我意识到我的视图是0高度和0宽度，因为我使用的是TextView。所以我设法等到视图（TextView）将加载并在开始创建文档后，看一下代码，希望你能解决它：

    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.fragment_main);

     final TextView tv = (TextView) findViewById(R.id.textView1);
        ViewTreeObserver vto = tv.getViewTreeObserver(); 
        vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() { 
            @Override 
            public void onGlobalLayout() { 
                Toast.makeText(MainActivity.this, tv.getWidth() + " x " + tv.getHeight(), Toast.LENGTH_LONG).show();    

                try {
                    File file1 = new File("/mnt/sdcard/test/");
                    if(!file1.exists()){
                        file1.mkdirs();
                    }

                    File file = new File("/mnt/sdcard/test", "filename"+System.currentTimeMillis()+".pdf");
                    PrintAttributes printAttrs = new PrintAttributes.Builder().
                            setColorMode(PrintAttributes.COLOR_MODE_COLOR).
                            setMediaSize(PrintAttributes.MediaSize.ISO_A4).
                            setResolution(new Resolution("zooey", PRINT_SERVICE, 450, 700)).
                            setMinMargins(Margins.NO_MARGINS).
                            build();
                    PdfDocument document = new PrintedPdfDocument(MainActivity.this, printAttrs);
                     PageInfo pageInfo = new PageInfo.Builder(450, 700, 1).create();
                     Page page = document.startPage(pageInfo);

                     if (page != null) {

                           View view = findViewById(R.id.textView1);//getContentView();                          
                           view.layout(0, 0, view.getWidth(),
                                   view.getHeight());
                           Log.i("draw view", " content size: "+view.getWidth()+" / "+view.getHeight());
                           view.draw(page.getCanvas());
                           // Move the canvas for the next view.
                           page.getCanvas().translate(0, view.getHeight());
                       }    

                     document.finishPage(page);
                     os = new FileOutputStream(file);
                            document.writeTo(os);
                            document.close();
                            os.close();
                            Log.i("done", file.getAbsolutePath().toString());

                        } catch (IOException e) {
                            throw new RuntimeException("Error generating file", e);
                        }

                tv.getViewTreeObserver().removeGlobalOnLayoutListener(this);
            } 
        });

}

里面的魔力：

 final TextView tv = (TextView) findViewById(R.id.textView1);
        ViewTreeObserver vto = tv.getViewTreeObserver(); 
        vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() { 
            @Override 
            public void onGlobalLayout() { 
         // create document here
} 
        });

Answer 2

如果某人正在动态创建布局，并且没有将其视图附加到活动或片段，这些活动或片段在活动或片段生命周期的某个时刻被渲染和测量，则还有另一种方法：

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

这样你的rootView宽度和高度就不会保持为0，并且会有一些东西会被渲染到文档中。感谢the answer here！

Answer 3

最能帮助我的例子就是Android Cookbook中可以找到的那个例子。您可以在github account。

中找到相应的代码

将该代码与用于编写的代码混合，您将拥有它：

@TargetApi(Build.VERSION_CODES.KITKAT)
public void run() {
    // Create a shiny new (but blank) PDF document in memory
    // We want it to optionally be printable, so add PrintAttributes
    // and use a PrintedPdfDocument. Simpler: new PdfDocument().
    PrintAttributes printAttrs = new PrintAttributes.Builder().
            setColorMode(PrintAttributes.COLOR_MODE_COLOR).
            setMediaSize(PrintAttributes.MediaSize.NA_LETTER).
            setResolution(new PrintAttributes.Resolution("zooey", PRINT_SERVICE, 300, 300)).
            setMinMargins(PrintAttributes.Margins.NO_MARGINS).
            build();
    PdfDocument document = new PrintedPdfDocument(this, printAttrs);
    // crate a page description
    PdfDocument.PageInfo pageInfo = new PdfDocument.PageInfo.Builder(300, 300, 1).create();
    // create a new page from the PageInfo
    PdfDocument.Page page = document.startPage(pageInfo);
    // repaint the user's text into the page
    View content = findViewById(R.id.textArea);
    content.draw(page.getCanvas());
    // do final processing of the page
    document.finishPage(page);
    // Here you could add more pages in a longer doc app, but you'd have
    // to handle page-breaking yourself in e.g., write your own word processor...
    // Now write the PDF document to a file; it actually needs to be a file
    // since the Share mechanism can't accept a byte[]. though it can
    // accept a String/CharSequence. Meh.
    try {
        File f = new File(Environment.getExternalStorageDirectory().getPath() + "/pruebaAppModerator.pdf");
        FileOutputStream fos = new FileOutputStream(f);
        document.writeTo(fos);
        document.close();
        fos.close();            
    } catch (IOException e) {
        throw new RuntimeException("Error generating file", e);
    }
}

Answer 4

我有完全相同的问题，但为了实现@ user2021505解决方案（有效）我应该做一个主要的重构，所以我这样解决了问题

// ...
PdfDocument.Page page = document.startPage(pageInfo);

TextView textView = new TextView(ctx);
textView.setText("1,2,3");

// here the solution
int left = 0;
int top = 0;
int width = 200;
int height = 200;
textView.layout(0,0,width,height);

canvas.save()
canvas.translate(left,top);

textView.draw(page.getCanvas());

canvas.restore()

Answer 5

首先需要添加依赖

implementation group: 'com.itextpdf', name: 'itextpdf', version: '5.3.2'

然后在空白的 PDF 文档上设置位图

            PdfDocument pdfDocument =  new PdfDocument();
            PdfDocument.PageInfo pi = new 
            PdfDocument.PageInfo.Builder(mBitmap.getWidth(), 
            mBitmap.getHeight(),1).create();

            PdfDocument.Page page = pdfDocument.startPage(pi);
            Canvas canvas = page.getCanvas();
            Paint paint = new Paint();
            paint.setColor(Color.parseColor("#FFFFFF"));
            canvas.drawPaint(paint);

            mBitmap = Bitmap.createScaledBitmap(mBitmap, 
            mBitmap.getWidth(),mBitmap.getHeight(), true);
            paint.setColor(Color.BLUE);
            canvas.drawBitmap(mBitmap,0,0,null);
            pdfDocument.finishPage(page);
            pdfDocument.close();

Android：PdfDocument生成空pdf

5 个答案: