title: Android Studio - Enable native C++ debugging in existing older project (card.io Android Source)
body: <p>I am currently trying to understand how the native implementation of the <a href="https://github.com/card-io/card.io-Android-source" rel="noreferrer">card.io Android Source</a> does work. For this purpose, it would be great to have the possibility to debug the native <code>C++</code> code. Currently, my breakpoints are not respected. </p>
  
  <p>I did try the following approaches:</p>
  
  <ol>
  <li>Adjust the Application make file (Application.mk):</li>
  </ol>
  
  <p><code>APP_ABI := armeabi-v7a
   APP_CFLAGS += -UNDEBUG -O0 -g -ggdb 
   APP_OPTIM := debug
   APP_CPPFLAGS += -DDMZ_DEBUG=1</code></p>
  
  <ol start="2">
  <li>Add buildtype to the build.gradle file of the SampleApp</li>
  </ol>
  
  <p><code>buildTypes {
          release {
              minifyEnabled true
              proguardFile getDefaultProguardFile('proguard-android.txt')
          }
          debug {
              debuggable true
          }
      }</code></p>
  
  <p><strong>Note:</strong>
  I am using <code>Android Studio 3.1</code> with <code>Ubuntu 16.04</code> <em>(64-bit)</em> and if I create a new project with <code>C++</code> support, debugging is perfectly working.</p>
  
  <p>We are debugging on an <code>Android 7.0</code> device; the project is using an <code>NDK-build</code> system.</p>