在Android中生成Pdf的缩略图 [英] Generate Thumbnail of Pdf in Android

问题描述

我想从pdf文件生成图像（缩略图），就像 WhatsApp 一样，如下所示

I want to generate the image(thumbnail) from pdf file just like done by WhatsApp as shown below

我试过了

1. PDFBox （ https://github.com/TomRoush/PdfBox-Android ）


2. Tika （编译'org.apache.tika：tika-parsers：1.11'）


3. AndroidPdfViewer （ https://github.com/barteksc/AndroidPdfViewer ）

1. PDFBox (https://github.com/TomRoush/PdfBox-Android)
2. Tika (compile 'org.apache.tika:tika-parsers:1.11')
3. AndroidPdfViewer (https://github.com/barteksc/AndroidPdfViewer)

仍然无法找到从pdf生成图像的方法。

and still unable to find a way to generate image from pdf.

PDFBox：

PDFBox:

有一个github问题可以解决这个问题（ https://github.com/TomRoush/PdfBox-Android/issues/3 ）但这仍然没有得到解决。

There is a github issue that deals with this problem (https://github.com/TomRoush/PdfBox-Android/issues/3) but this is still unresolved.

注意：我已成功使用 PDFBOX

AndroidPdfViewer：

AndroidPdfViewer:

Github问题（ https://github.com/barteksc/AndroidPdfViewer/issues/49 ）

Github issue (https://github.com/barteksc/AndroidPdfViewer/issues/49)

推荐答案

使用 PdfiumAndroid github.com/barteksc/AndroidPdfViewer/issues/49rel =noreferrer> barteksc 这里......

Use PdfiumAndroid as mentioned by barteksc here...

生成pdf thumb的示例代码

Sample Code for generating pdf thumb

//PdfiumAndroid (https://github.com/barteksc/PdfiumAndroid)
//https://github.com/barteksc/AndroidPdfViewer/issues/49
void generateImageFromPdf(Uri pdfUri) {
    int pageNumber = 0;
    PdfiumCore pdfiumCore = new PdfiumCore(this);
    try {
        //http://www.programcreek.com/java-api-examples/index.php?api=android.os.ParcelFileDescriptor
        ParcelFileDescriptor fd = getContentResolver().openFileDescriptor(pdfUri, "r");
        PdfDocument pdfDocument = pdfiumCore.newDocument(fd);
        pdfiumCore.openPage(pdfDocument, pageNumber);
        int width = pdfiumCore.getPageWidthPoint(pdfDocument, pageNumber);
        int height = pdfiumCore.getPageHeightPoint(pdfDocument, pageNumber);
        Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        pdfiumCore.renderPageBitmap(pdfDocument, bmp, pageNumber, 0, 0, width, height);
        saveImage(bmp);
        pdfiumCore.closeDocument(pdfDocument); // important!
    } catch(Exception e) {
        //todo with exception
    }
}

public final static String FOLDER = Environment.getExternalStorageDirectory() + "/PDF";
private void saveImage(Bitmap bmp) {
    FileOutputStream out = null;
    try {
        File folder = new File(FOLDER);
        if(!folder.exists())
            folder.mkdirs();
        File file = new File(folder, "PDF.png");
        out = new FileOutputStream(file);
        bmp.compress(Bitmap.CompressFormat.PNG, 100, out); // bmp is your Bitmap instance
    } catch (Exception e) {
        //todo with exception
    } finally {
        try {
            if (out != null)
                out.close();
        } catch (Exception e) {
            //todo with exception
        }
    }
}

---

更新：

包括build.gradle中的库

Include library in build.gradle

compile 'com.github.barteksc:pdfium-android:1.4.0'

用于生成任何PDF页面的图像：

通过传递存储在存储中的任何 PDF uri 来调用方法 generateImageFromPdf（uri）。

Call the method generateImageFromPdf(uri) by passing any PDF uri that is stored in your storage.

该方法将在您存储的PDF文件夹中生成 PDF.png 。

The method will generate the PDF.png in PDF folder of your storage.

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