Archives for 17 Jan,2010

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Android: Blurring and dimming background windows from dialogs

The android SDK has lots of nice goodies built in to make your applications look sexier. One such feature is the blurring of windows. This effect looks particularly nice if a background window is blurred while a dialog box is shown above which can really make it stand out. Below shows the application such an example; on the left is the default about box (for WordCube Pro) and on the right is with added blur and no dimming.

android blur dim, before, after

android bluring and dimming effect before and after

I am using the AlterDialog.Builder to create my dialog, however this method will work with all kinds of dialog providing you can access it via getWindow.

   dialog = new AlertDialog.Builder(WordCube.this)
   .setPositiveButton(R.string.btn_close, null)

Below shows the code needed to add blur and remove dimming of the background (as I think the blur looks nicer when the background is well lit).

WindowManager.LayoutParams lp = dialog.getWindow().getAttributes();

The blur is simply created using the last line (line 4) which sets a flag for the dialog telling android that we want windows below this one to be blurred. To achieve the dimming, we need to retrieve the layout parameters for the dialog window, set the dim amount to zero, update these parameters with setAttributes (lines 1-3).

Any comments, questions, or improvements please let me know.

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Android: Requesting root access in your app

This snippet shows how root access can be requested inside an application in order to write a file into a place we do not have permission to access usually. Requesting root access will only work if your phone allows it, or it has been ‘rooted’ (hacked to allow superuser permissions).

Process p; 
try { 
   // Preform su to get root privledges
   p = Runtime.getRuntime().exec("su"); 
   // Attempt to write a file to a root-only 
   DataOutputStream os = new DataOutputStream(p.getOutputStream()); 
   os.writeBytes("echo \"Do I have root?\" >/system/sd/temporary.txt\n");
   // Close the terminal
   try { 
           if (p.exitValue() != 255) { 
        	  // TODO Code to run on success
           else { 
        	   // TODO Code to run on unsuccessful
        	   toastMessage("not root");    
   } catch (InterruptedException e) { 
      // TODO Code to run in interrupted exception
	   toastMessage("not root"); 
} catch (IOException e) { 
   // TODO Code to run in input/output exception
	toastMessage("not root"); 

Where my “toastMessage” is just a function which creates a toast to display on the screen. On phones with superuser permissions installed (root access) this will display a dialog asking the user to allow or deny the application permission to have root access:

android root access dialog

android request root access dialog


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