Question

我正在尝试在我的应用内创建一个pdf文件，将其保存在打开它的外部存储上。保存文件对我来说不是问题，也不是打开文件，我的问题是创建文件并写入文件。因此，在网上进行一些研究后，我发现了以下方法：

        File file = new File(directoryName, fileName);

        // Creating output stream to write in the newly created file
        FileOutputStream fOut = null;

        try {
            fOut = new FileOutputStream(file);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

        // Creating a new document
        Document document = new Document(PageSize.A4, 50, 50, 50, 50);

        try {
            PdfWriter.getInstance(document, fOut);

            // Open the document for writing
            document.open();

            // Write in the document
            document.add(new Paragraph("Hello world"));
            document.close();

        } catch(DocumentException de) {
            System.err.println(de.getMessage());
        }

运行我的应用程序并执行上面的代码后，我收到以下错误：

java.lang.NoClassDefFoundError: Failed resolution of: Ljava/awt/Color;

有人知道我的代码有什么问题，或者其他确保用于创建和编写pdf文件的方法有什么问题吗？

谢谢！

Answer 1

显然我使用的代码与android不兼容，因此我得到的错误。在下面，您将找到实际正常工作的正确代码（用于创建pdf文件，在其中放入一些内容，保存并打开新创建的文件）：

PS：为此，您需要将iTextG的jar添加到您的项目中：

// Method for creating a pdf file from text, saving it then opening it for display
    public void createandDisplayPdf(String text) {

        Document doc = new Document();

        try {
            String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/Dir";

            File dir = new File(path);
            if(!dir.exists())
                dir.mkdirs();

            File file = new File(dir, "newFile.pdf");
            FileOutputStream fOut = new FileOutputStream(file);

            PdfWriter.getInstance(doc, fOut);

            //open the document
            doc.open();

            Paragraph p1 = new Paragraph(text);
            Font paraFont= new Font(Font.COURIER);
            p1.setAlignment(Paragraph.ALIGN_CENTER);
            p1.setFont(paraFont);

            //add paragraph to document
            doc.add(p1);    

        } catch (DocumentException de) {
            Log.e("PDFCreator", "DocumentException:" + de);
        } catch (IOException e) {
            Log.e("PDFCreator", "ioException:" + e);
        }
        finally {
            doc.close();
        }

        viewPdf("newFile.pdf", "Dir");
    }

    // Method for opening a pdf file
    private void viewPdf(String file, String directory) {

        File pdfFile = new File(Environment.getExternalStorageDirectory() + "/" + directory + "/" + file);
        Uri path = Uri.fromFile(pdfFile);

        // Setting the intent for pdf reader
        Intent pdfIntent = new Intent(Intent.ACTION_VIEW);
        pdfIntent.setDataAndType(path, "application/pdf");
        pdfIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

        try {
            startActivity(pdfIntent);
        } catch (ActivityNotFoundException e) {
            Toast.makeText(TableActivity.this, "Can't read pdf file", Toast.LENGTH_SHORT).show();
        }
    }

Answer 2

PdfDocument类可以从原生Android内容生成PDF文档。通过使用这个类，我们可以创建pdf并使用PdfRenderer打开它。用于创建pdf文件的示例代码

 public void stringtopdf(String data)  {
    String extstoragedir = Environment.getExternalStorageDirectory().toString();
    File fol = new File(extstoragedir, "pdf");
    File folder=new File(fol,"pdf");
    if(!folder.exists()) {
        boolean bool = folder.mkdir();
    }
    try {
        final File file = new File(folder, "sample.pdf");
        file.createNewFile();
        FileOutputStream fOut = new FileOutputStream(file);


        PdfDocument document = new PdfDocument();
        PdfDocument.PageInfo pageInfo = new 
        PdfDocument.PageInfo.Builder(100, 100, 1).create();
        PdfDocument.Page page = document.startPage(pageInfo);
        Canvas canvas = page.getCanvas();
        Paint paint = new Paint();

        canvas.drawText(data, 10, 10, paint);



        document.finishPage(page);
        document.writeTo(fOut);
        document.close();

    }catch (IOException e){
        Log.i("error",e.getLocalizedMessage());
    }

Answer 3

从此处下载源代码（Create pdf file in android programmatically）

<强> activity_main.xml中：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ffffff"
    android:orientation="vertical">

    <Button
        android:id="@+id/btn_generate"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Generate PDF" />

    <LinearLayout
        android:layout_width="match_parent"
        android:orientation="vertical"
        android:id="@+id/ll_pdflayout"
        android:background="#ffffff"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/iv_image"
            android:src="@drawable/image"
            android:layout_width="300dp"
            android:scaleType="fitXY"
            android:layout_marginTop="10dp"
            android:layout_gravity="center"
            android:layout_height="250dp" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="14dp"
            android:text="Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum."
            android:layout_marginTop="10dp"
            android:gravity="center"
            android:paddingLeft="10dp"
            android:paddingRight="10dp"
            android:textColor="#000000"/>


        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/tv_link"
            android:textSize="10dp"
            android:textColor="#000000"/>


    </LinearLayout>

</LinearLayout>

<强> MainActivity.java

package com.deepshikha.generatepdf;

import android.Manifest;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.pdf.PdfDocument;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    Button btn_generate;
    TextView tv_link;
    ImageView iv_image;
    LinearLayout ll_pdflayout;
    public static int REQUEST_PERMISSIONS = 1;
    boolean boolean_permission;
    boolean boolean_save;
    Bitmap bitmap;
    ProgressDialog progressDialog;

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


    private void init(){
        btn_generate = (Button)findViewById(R.id.btn_generate);
        tv_link = (TextView)findViewById(R.id.tv_link);
        iv_image = (ImageView) findViewById(R.id.iv_image);
        ll_pdflayout = (LinearLayout) findViewById(R.id.ll_pdflayout);

    }

    private void listener(){
        btn_generate.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {

        switch (view.getId()) {
            case R.id.btn_generate:

                if (boolean_save) {
                    Intent intent = new Intent(getApplicationContext(), PDFViewActivity.class);
                    startActivity(intent);

                } else {
                    if (boolean_permission) {
                        progressDialog = new ProgressDialog(MainActivity.this);
                        progressDialog.setMessage("Please wait");
                         bitmap = loadBitmapFromView(ll_pdflayout, ll_pdflayout.getWidth(), ll_pdflayout.getHeight());
                        createPdf();
//                        saveBitmap(bitmap);
                    } else {

                    }

                    createPdf();
                    break;
                }
        }
    }

    private void createPdf(){
        WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        DisplayMetrics displaymetrics = new DisplayMetrics();
        this.getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
        float hight = displaymetrics.heightPixels ;
        float width = displaymetrics.widthPixels ;

        int convertHighet = (int) hight, convertWidth = (int) width;

//        Resources mResources = getResources();
//        Bitmap bitmap = BitmapFactory.decodeResource(mResources, R.drawable.screenshot);

        PdfDocument document = new PdfDocument();
        PdfDocument.PageInfo pageInfo = new PdfDocument.PageInfo.Builder(convertWidth, convertHighet, 1).create();
        PdfDocument.Page page = document.startPage(pageInfo);

        Canvas canvas = page.getCanvas();


        Paint paint = new Paint();
        canvas.drawPaint(paint);


        bitmap = Bitmap.createScaledBitmap(bitmap, convertWidth, convertHighet, true);

        paint.setColor(Color.BLUE);
        canvas.drawBitmap(bitmap, 0, 0 , null);
        document.finishPage(page);


        // write the document content
        String targetPdf = "/sdcard/test.pdf";
        File filePath = new File(targetPdf);
        try {
            document.writeTo(new FileOutputStream(filePath));
            btn_generate.setText("Check PDF");
            boolean_save=true;
        } catch (IOException e) {
            e.printStackTrace();
            Toast.makeText(this, "Something wrong: " + e.toString(), Toast.LENGTH_LONG).show();
        }

        // close the document
        document.close();
    }



    public static Bitmap loadBitmapFromView(View v, int width, int height) {
        Bitmap b = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(b);
        v.draw(c);

        return b;
    }

    private void fn_permission() {
        if ((ContextCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)||
                (ContextCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)) {

            if ((ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this, android.Manifest.permission.READ_EXTERNAL_STORAGE))) {
            } else {
                ActivityCompat.requestPermissions(MainActivity.this, new String[]{android.Manifest.permission.READ_EXTERNAL_STORAGE},
                        REQUEST_PERMISSIONS);

            }

            if ((ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE))) {
            } else {
                ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                        REQUEST_PERMISSIONS);

            }
        } else {
            boolean_permission = true;


        }
    }
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_PERMISSIONS) {

            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                boolean_permission = true;


            } else {
                Toast.makeText(getApplicationContext(), "Please allow the permission", Toast.LENGTH_LONG).show();

            }
        }
    }


}

谢谢！

Answer 4

您可以像下面这样使用波纹管。

pdf将喜欢下面的内容。

activity_main.xml

<Button
    android:id="@+id/btnCreatePdf"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Create PDF" />

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"
    android:gravity="center"
    android:orientation="vertical">

    <TextView
        android:id="@+id/tv_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center_vertical"
        android:singleLine="true"
        android:text="Thank You!"
        android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium"
        android:textSize="20sp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/tv_sub_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center_vertical"
        android:singleLine="true"
        android:text="Your transaction is successful"
        android:textAppearance="@style/Base.TextAppearance.AppCompat.Small"
        android:textSize="16sp" />

</LinearLayout>

<View
    android:layout_width="match_parent"
    android:layout_height="1dp"
    android:background="#e6e6e6" />

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dp"
    android:orientation="vertical"
    android:padding="10dp">

    <TextView
        android:id="@+id/tv_location"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Location" />

    <TextView
        android:id="@+id/tv_city"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="5dp"
        android:text="Dhaka"
        android:textStyle="bold" />

</LinearLayout>

MainActivity ：

 public class MainActivity extends AppCompatActivity {
    Button btnCreatePdf;
    TextView tv_title;
    TextView tv_sub_title;
    TextView tv_location;
    TextView tv_city;


   String file_name_path = "";
   int PERMISSION_ALL = 1;
   String[] PERMISSIONS = {

    android.Manifest.permission.WRITE_EXTERNAL_STORAGE,
    android.Manifest.permission.READ_EXTERNAL_STORAGE,

   };


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

    StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
    StrictMode.setVmPolicy(builder.build());

     if (!hasPermissions(MainActivity.this, PERMISSIONS)) {
    ActivityCompat.requestPermissions(MainActivity.this, PERMISSIONS, PERMISSION_ALL);
    }

      File file = new File(this.getExternalFilesDir(null).getAbsolutePath(), "pdfsdcard_location");
   if (!file.exists()) {
    file.mkdir();
}

btnCreatePdf = findViewById(R.id.btnCreatePdf);
tv_title = findViewById(R.id.tv_title);
tv_sub_title = findViewById(R.id.tv_sub_title);
tv_location = findViewById(R.id.tv_location);
tv_city = findViewById(R.id.tv_city);


 btnCreatePdf.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        createpdf();
     }
    });

  }


public void createpdf() {
    Rect bounds = new Rect();
    int pageWidth = 300;
    int pageheight = 470;
    int pathHeight = 2;

    final String fileName = "mypdf";
     file_name_path = "/pdfsdcard_location/" + fileName + ".pdf";
    PdfDocument myPdfDocument = new PdfDocument();
    Paint paint = new Paint();
    Paint paint2 = new Paint();
    Path path = new Path();
    PdfDocument.PageInfo myPageInfo = new PdfDocument.PageInfo.Builder(pageWidth, pageheight, 1).create();
   PdfDocument.Page documentPage = myPdfDocument.startPage(myPageInfo);
   Canvas canvas = documentPage.getCanvas();
   int y = 25; // x = 10,
   int x = 10;

   paint.getTextBounds(tv_title.getText().toString(), 0, tv_title.getText().toString().length(), bounds);
x = (canvas.getWidth() / 2) - (bounds.width() / 2);
canvas.drawText(tv_title.getText().toString(), x, y, paint);

   paint.getTextBounds(tv_sub_title.getText().toString(), 0, tv_sub_title.getText().toString().length(), bounds);
  x = (canvas.getWidth() / 2) - (bounds.width() / 2);
  y += paint.descent() - paint.ascent();
 canvas.drawText(tv_sub_title.getText().toString(), x, y, paint);

  y += paint.descent() - paint.ascent();
 canvas.drawText("", x, y, paint);

//horizontal line
path.lineTo(pageWidth, pathHeight);
paint2.setColor(Color.GRAY);
paint2.setStyle(Paint.Style.STROKE);
path.moveTo(x, y);

canvas.drawLine(0, y, pageWidth, y, paint2);

//blank space
y += paint.descent() - paint.ascent();
canvas.drawText("", x, y, paint);

y += paint.descent() - paint.ascent();
x = 10;
canvas.drawText(tv_location.getText().toString(), x, y, paint);

y += paint.descent() - paint.ascent();
x = 10;
canvas.drawText(tv_city.getText().toString(), x, y, paint);

//blank space
y += paint.descent() - paint.ascent();
canvas.drawText("", x, y, paint);

//horizontal line
path.lineTo(pageWidth, pathHeight);
paint2.setColor(Color.GRAY);
paint2.setStyle(Paint.Style.STROKE);
path.moveTo(x, y);
canvas.drawLine(0, y, pageWidth, y, paint2);

//blank space
y += paint.descent() - paint.ascent();
canvas.drawText("", x, y, paint);

Resources res = getResources();
Bitmap bitmap = BitmapFactory.decodeResource(res, R.drawable.logo);
Bitmap b = (Bitmap.createScaledBitmap(bitmap, 100, 50, false));
canvas.drawBitmap(b, x, y, paint);
y += 25;
canvas.drawText(getString(R.string.app_name), 120, y, paint);


myPdfDocument.finishPage(documentPage);

File file = new File(this.getExternalFilesDir(null).getAbsolutePath() + file_name_path);
try {
    myPdfDocument.writeTo(new FileOutputStream(file));
} catch (IOException e) {
    e.printStackTrace();
}

  myPdfDocument.close();
  viewPdfFile();
 }

public void viewPdfFile() {

   File file = new File(this.getExternalFilesDir(null).getAbsolutePath() + file_name_path);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(file), "application/pdf");
   startActivity(intent);
 }


   public static boolean hasPermissions(Context context, String... permissions) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && context != null && permissions != null) {
    for (String permission : permissions) {
        if (ActivityCompat.checkSelfPermission(context, permission) != PackageManager.PERMISSION_GRANTED) {
            return false;
        }
      }
      }
   return true;
   }
}

不要忘记在清单文件中添加以下权限

  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

完整源代码，从GitHub下载：https://github.com/enamul95/CreatePdf.git

以编程方式在android中创建pdf文件并在其中书写

4 个答案: