如何从多个图像中制作 PDF

Question

我正在构建一个应用程序来将图像上传到我公司的服务器我现在正致力于拍摄多张图像并将它们转换为 PDF，以便属于同一文档的图像可以放在一起[=13=]

我的问题是我不知道如何制作它以便我可以将多个图像添加到 PDF 创建我正在使用 Kosal Geek 的 android 库 PhotoUtils 进行图像处理和 PDFdocument 来创建 pdf

目前单个图像有效，但如果我 select 多个图像，我会得到空指针异常

主要代码

public class PdfMake extends AppCompatActivity {
    private final int PICK_IMAGE=12345;
    private final int REQUEST_CAMERA=6352;
    CameraPhoto cameraPhoto;
    GalleryPhoto galleryPhoto;
    String selectedPhoto;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        StrictMode.VmPolicy.Builder builder4=new StrictMode.VmPolicy.Builder();
        StrictMode.setVmPolicy(builder4.build());
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_pdf_make);
        Button fromCamera=findViewById(R.id.SelectImages2);
        Button PdfMake=findViewById(R.id.button4);

        fromCamera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showPictureDialog();
            }
        });
        PdfMake.setOnClickListener(new View.OnClickListener() {
            @RequiresApi(api=Build.VERSION_CODES.KITKAT)
            @Override
            public void onClick(View v) {
                try {
                    createPdf();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }
        private void showPictureDialog () {
            AlertDialog.Builder pictureDialog=new AlertDialog.Builder(this);
            pictureDialog.setTitle("Select Action");
            String[] pictureDialogItems={
                    "Select photo from gallery",
                    "Capture photo from camera"};
            pictureDialog.setItems(pictureDialogItems,
                    new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            switch (which) {
                                case 0:
                                    getImageFromGallery();
                                    break;
                                case 1:
                                    try {
                                        getImageFromCamera();
                                    } catch (IOException e) {
                                        e.printStackTrace();
                                    }
                                    break;

                            }
                        }
                    });

        }




    @RequiresApi(api=Build.VERSION_CODES.KITKAT)
    private void createPdf() throws IOException {
        // create a new document
        PdfDocument document=new PdfDocument();
        // crate a page description
        PdfDocument.PageInfo pageInfo=new PdfDocument.PageInfo.Builder(3000, 6000, 1).create();
        // start a page
        PdfDocument.Page page=document.startPage(pageInfo);
        Canvas canvas=page.getCanvas();
        Bitmap image=BitmapFactory.decodeFile(selectedPhoto);
        canvas.drawBitmap(image, 10, 10, null);

        document.finishPage(page);
        String directory_path=Environment.getExternalStorageDirectory().getPath() + "/mypdf/";
        File file=new File(directory_path);
        if (!file.exists()) {
            file.mkdirs();
        }
        String targetPdf=directory_path + "test-2.pdf";
        File filePath=new File(targetPdf);
        try {
            document.writeTo(new FileOutputStream(filePath));
            Toast.makeText(this, "Done", Toast.LENGTH_LONG).show();
        } catch (IOException e) {
            Log.e("main", "error " + e.toString());
            Toast.makeText(this, "Something wrong: " + e.toString(), Toast.LENGTH_LONG).show();
        }
        // close the document
        document.close();
    }



        private void getImageFromCamera () throws IOException {

            cameraPhoto=new CameraPhoto(getApplicationContext());
            Intent in=cameraPhoto.takePhotoIntent();
            startActivityForResult(in, REQUEST_CAMERA);
            Bungee.split(PdfMake.this);

        }

        private void getImageFromGallery () {

        Intent intent=new Intent();
            intent.setType("image/*");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
                intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
            }
            if (intent.resolveActivity(getPackageManager()) != null) {
                startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE);
                Bungee.split(PdfMake.this);

            }
        }


protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
        if (requestCode == REQUEST_CAMERA) {


        String photoPath=cameraPhoto.getPhotoPath();
        selectedPhoto=photoPath;
        try {
        Bitmap bitmap=ImageLoader.init().from(photoPath).requestSize(512, 512).getBitmap();
        } catch (FileNotFoundException e) {
        Toasty.error(getApplicationContext(),
        "Something Wrong while loading photos", Toast.LENGTH_SHORT).show();
        }

        } else if (requestCode == PICK_IMAGE) {
        Uri uri=data.getData();

        galleryPhoto.setPhotoUri(uri);
        String photoPath=galleryPhoto.getPath();
        selectedPhoto=photoPath;
        try {
        Bitmap bitmap=ImageLoader.init().from(photoPath).requestSize(512, 512).getBitmap();
        } catch (FileNotFoundException e) {
        Toasty.error(getApplicationContext(),
        "Something Wrong while choosing photos", Toast.LENGTH_SHORT).show();
        }
        }
        }
        }
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        int CAMERA_RESULT=11100;
        if(requestCode == CAMERA_RESULT){
        if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED){
        try {
        getImageFromCamera();
        } catch (IOException e) {
        e.printStackTrace();
        }
        }
        else{
        Toasty.error(getApplicationContext(), "Permission Needed.", Toast.LENGTH_LONG).show();
        }
        }
        else {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
        if(requestCode == PICK_IMAGE){
        if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED){
        getImageFromGallery();
        }
        else{
        Toasty.error(getApplicationContext(), "Permission Needed.", Toast.LENGTH_LONG).show();
        }
        }
        else {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
        }
}

画廊图片代码

public class GalleryPhoto {
    final String TAG = this.getClass().getSimpleName();
    private Context context;
    private Uri photoUri;

    public void setPhotoUri(Uri photoUri) {
        this.photoUri = photoUri;
    }

    public GalleryPhoto(Context context) {
        this.context = context;
    }

    public Intent openGalleryIntent() {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction("android.intent.action.GET_CONTENT");
        return Intent.createChooser(intent, this.getChooserTitle());
    }

    public String getChooserTitle() {
        return "Select Pictures";
    }

    public String getPath() {
        String path;
        if (VERSION.SDK_INT < 11) {
            path = RealPathUtil.getRealPathFromURI_BelowAPI11(this.context, this.photoUri);
        } else if (VERSION.SDK_INT < 19) {
            path = RealPathUtil.getRealPathFromURI_API11to18(this.context, this.photoUri);
        } else {
            path = RealPathUtil.getRealPathFromURI_API19(this.context, this.photoUri);
        }

        return path;
    }
}

相机图像代码

public class CameraPhoto {
    final String TAG = this.getClass().getSimpleName();
    private String photoPath;
    private Context context;

    public String getPhotoPath() {
        return this.photoPath;
    }

    public CameraPhoto(Context context) {
        this.context = context;
    }

    public Intent takePhotoIntent() throws IOException {
        Intent in = new Intent("android.media.action.IMAGE_CAPTURE");
        if (in.resolveActivity(this.context.getPackageManager()) != null) {
            File photoFile = this.createImageFile();
            if (photoFile != null) {
                in.putExtra("output", Uri.fromFile(photoFile));
            }
        }

        return in;
    }

    private File createImageFile() throws IOException {
        String timeStamp = (new SimpleDateFormat("yyyyMMdd_HHmmss")).format(new Date());
        String imageFileName = "JPEG_" + timeStamp + "_";
        File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
        File image = File.createTempFile(imageFileName, ".jpg", storageDir);
        this.photoPath = image.getAbsolutePath();
        return image;
    }

    public void addToGallery() {
        Intent mediaScanIntent = new Intent("android.intent.action.MEDIA_SCANNER_SCAN_FILE");
        File f = new File(this.photoPath);
        Uri contentUri = Uri.fromFile(f);
        mediaScanIntent.setData(contentUri);
        this.context.sendBroadcast(mediaScanIntent);
    }
}

Answer 1

有一个不错的库，叫做 "Android PDF Writer"。

您要做的是在其中创建一个 PDF 对象和一个页面。

PDFWriter mPDFWriter = new PDFWriter(PaperSize.FOLIO_WIDTH, PaperSize.FOLIO_HEIGHT);

然后您可以通过 addImage 添加图片，通过 newPage()

添加页面

您可以在项目demo page here中看到一个演示。

如何从多个图像中制作 PDF

How Can I make a PDF out of Multiple Images

java

android

android-studio

pdfdocument