iTextG causing application crash(Android)

问题

My objective is to superimpose contents of a pdf onto another PDF.

this is the code that I have used:

AssetManager assetManager = getAssets();
    InputStream istr = null;
    PdfReader reader = null;
    String str = null;
    int n = 0;
    try
    {                       
        istr =(InputStream) assetManager.open("Chemistry.pdf");

        reader=new PdfReader(istr);     




        Document document = new Document();
      PdfWriter writer=  PdfWriter.getInstance(document, new FileOutputStream(Environment.getExternalStorageDirectory()+ "/newhelloPrayToGod.pdf"));


        document.open();

        document.add(new Paragraph("Hello World"));
        document.newPage();
        PdfContentByte canvas = writer.getDirectContent();
        PdfImportedPage page;

        page = writer.getImportedPage(reader, 23);
        canvas.addTemplate(page, 1, 0, 0, 0, 0, 0);



        document.close();

        Log.d("OK", "done");
    }
    catch (FileNotFoundException e)
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (DocumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

I have used itextG 5.4.3. I have even added a copy of the .jar in my libs folder. The code compiles, but on running, it just crashes. This is the error log:

03-28 16:27:36.693: E/AndroidRuntime(1037): FATAL EXCEPTION: main 03-28 16:27:36.693: E/AndroidRuntime(1037): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.teest/com.example.teest.MainActivity}: java.lang.ClassCastException: android.content.res.AssetManager$AssetInputStream cannot be cast to com.itextpdf.text.pdf.codec.Base64$InputStream 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.app.ActivityThread.access$600(ActivityThread.java:141) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.os.Handler.dispatchMessage(Handler.java:99) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.os.Looper.loop(Looper.java:137) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.app.ActivityThread.main(ActivityThread.java:5039) 03-28 16:27:36.693: E/AndroidRuntime(1037): at java.lang.reflect.Method.invokeNative(Native Method) 03-28 16:27:36.693: E/AndroidRuntime(1037): at java.lang.reflect.Method.invoke(Method.java:511) 03-28 16:27:36.693: E/AndroidRuntime(1037): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 03-28 16:27:36.693: E/AndroidRuntime(1037): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 03-28 16:27:36.693: E/AndroidRuntime(1037): at dalvik.system.NativeStart.main(Native Method) 03-28 16:27:36.693: E/AndroidRuntime(1037): Caused by: java.lang.ClassCastException: android.content.res.AssetManager$AssetInputStream cannot be cast to com.itextpdf.text.pdf.codec.Base64$InputStream 03-28 16:27:36.693: E/AndroidRuntime(1037): at com.example.teest.MainActivity.onCreate(MainActivity.java:36) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.app.Activity.performCreate(Activity.java:5104) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 03-28 16:27:36.693: E/AndroidRuntime(1037): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)

P.S. I have not used any license file(.xml) or anything of that sort. the above code is JUST what I have used.

I tried using the iText jar (not iTextG) too. In that, the code worked, but if I used this line in the code

canvas.addTemplate(page, 1, 0, 0, 0, 0, 0);

It would not compile with this error

The type java.awt.geom.AffineTransform cannot be resolved. It is indirectly referenced from required .class files

What do I do to get the canvas,addtemplate() running on android? I want to superimpose pdfs on another.

回答1:

I assume the exception occurs here:

istr =(InputStream) assetManager.open("Chemistry.pdf");

The exception

java.lang.ClassCastException: android.content.res.AssetManager$AssetInputStream cannot be cast to com.itextpdf.text.pdf.codec.Base64$InputStream

indicates that the InputStream in that code line is not the expected java.io variant.

Most likely you have an import like

import com.itextpdf.text.pdf.codec.Base64.InputStream

while you actually wanted

import java.io.InputStream

来源：https://stackoverflow.com/questions/22718443/itextg-causing-application-crashandroid