AndroidPDFViewer

This is simple example project how can you convert PDF file into images and use it like a very simple viewer. I wouldn't beleive how crazily bad is "free" showing PDF on Android :).

So after 1 day of testing different projects with a lot of memory leaks, TODOs, FIXMEs in a code, I found out it's not simple task at all.

This project uses MuPDF library for PDF stuff.

I took few classes in com.artifex.mupdf packages from some other project (can't find it now). I also used a very nice android control TouchImageView, I little updated it for usage inside ViewPager, so author(s) hopefully won't protest :).

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Download

https://github.com/jbruchanov/AndroidPDFViewer/raw/master/apk/PDF2JPG.apk

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How to use it:

For converting PDF page into JPG just use this

String file = "/sdcard/example.pdf"; //our PDF file
MuPDFCore core = new MuPDFCore(file); //initiate core
Bitmap b = PDFConvertHelper.convert(core, 0); //save 1st page into bitmap
PDFConvertHelper.saveBitmap(b,"/sdcard/example_page1.jpg"); //save bitmap into jpeg
core.onDestroy();//don't forget to release any handlers related to core

For android pdf viewer use this inside a android.support.v4.app.FragmentActivity (support library)

FragmentManager fm = getSupportFragmentManager();
String file = "/sdcard/example.pdf"
Fragment f = PDFViewFragment.newInstance(file);//just instantiate PDFViewFragment with argument

//open fragment, R.id.fragment_container is just view container, check activity_main.xml
fm.beginTransaction().add(R.id.fragment_container, f).commit();

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Obfuscation:

If you want to use this example in your app with obfuscation you have to keep field MuPDFCore.globals (not sure why is this field accessed from native code). Anyway for ProGuard it's very simple, just add this into your proguard-android.txt

#MuPDFCodre, we have too keep globals variable as is, otherwise crash...
-keepclassmembers class com.artifex.mupdf.MuPDFCore {
    private *** globals;
}

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Result:

So it's super simple, it works, it doesn't have memory leaks (i did just small memory allocation tests and looks fine). It doesn't have messy code coupled inside Activity, it's super simple Fragment...

It doesn't support any features like text selections, link clicking etc because it's converted into image. But this is what i needed basically, simple & functional PDF Viewer.

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Little math at the end:

Using Bitmaps is not much memory friendly. My example is just simple one. ViewPager needs up to 4 pages keep in memory. => 150dpi A4 page has 1240 x 1754. And if we have 4bytes per pixel it means that one Bitmap in memory takes ~8.3 MiB. So having 4 images in memory means allocate ~33MiB what is basically Heap limit for the oldest devices. I tested it on Samsung Galaxy Ace, which is crap and it worked (slowly, but worked :D). So be aware of using it with bigger-DPI documents or check in detail MuPDFCore#drawPage(int, int, int, int , int, int, int) (i didn't test it)...

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So do whatever you need to do :). Don't blame me if it doesn't work i just took few pieces of existing code and put them together, because no one probably did it in some nice and simple way yet.

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.