title: How to open locally saved files on cordova android
body: <p>I have a cordova application, which is caching a few files in the local file system, which I suppose is working (because on ios there are no problems at all and on android I can see the cached images).</p>
  
  <p>The problem is, when I want to display the PDF files on android (no matter if I use the inappbrowser plugin or cordova-plugin-file-opener2) the external window opens shortly and closes then immediatelly.
  In Android studio I get the following error message: 
  <code>E/Surface getSlotFromBufferLocked: unknown buffer: 0x96b20cc0</code></p>
  
  <p>If you search about that error, you get many posts about permission problems. But I dont know which permission I could need.</p>
  
  <p>Here is how I am opening the pdf files:</p>
  
  <pre><code>window.open("file:/// .... ", "_system");
  </code></pre>