android 用代码将pdf文件转换为图片

可以使用以下代码将PDF文件转换为图片：

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.pdf.PdfRenderer;
import android.os.Bundle;
import android.os.ParcelFileDescriptor;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    private ImageView imageView;

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

        imageView = findViewById(R.id.imageView);

        File pdfFile = new File("path/to/pdf/file.pdf");

        try {
            // create a new PdfRenderer object
            PdfRenderer renderer = new PdfRenderer(ParcelFileDescriptor.open(pdfFile, ParcelFileDescriptor.MODE_READ_ONLY));

            // get the number of pages in the PDF file
            final int pageCount = renderer.getPageCount();

            // get the first page of the PDF file
            PdfRenderer.Page page = renderer.openPage(0);

            // create a new bitmap object
            Bitmap bitmap = Bitmap.createBitmap(page.getWidth(), page.getHeight(), Bitmap.Config.ARGB_8888);

            // create a new canvas object
            Canvas canvas = new Canvas(bitmap);

            // set the background color of the canvas object
            canvas.drawColor(Color.WHITE);

            // render the PDF page into the canvas object
            page.render(bitmap, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);

            // set the bitmap image to the ImageView
            imageView.setImageBitmap(bitmap);

            // close the page object
            page.close();

            // close the renderer object
            renderer.close();

            // save the bitmap image as a JPEG file
            FileOutputStream out = new FileOutputStream("path/to/output/file.jpg");
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
            out.flush();
            out.close();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

注意替换代码中的文件路径。此代码将PDF文件的第一页转换为图片，并将其显示在ImageView中，然后将其保存为JPEG文件。你可以更改代码以转换多页PDF文件或更改输出图像的格式。