android: cap popup width on tablets and large screens (#521)

On tablets in landscape mode, the AirPods connection popup covers the
entire screen because width is set to MATCH_PARENT. This caps the popup
width to 400dp on screens wider than 600dp and centers it horizontally.

Also removes a duplicate gravity assignment in init that was overwriting
the CENTER_HORIZONTAL flag.

Fixes #425

Co-authored-by: TomasULR <creator_d@nvias.org>

android/app/src/main/java/me/kavishdevar/librepods/presentation/overlays/PopupWindow.kt

@@ -64,10 +64,16 @@ class PopupWindow(
     @Suppress("DEPRECATION")
     private val mParams: WindowManager.LayoutParams = WindowManager.LayoutParams().apply {
         height = WindowManager.LayoutParams.WRAP_CONTENT
-        width = WindowManager.LayoutParams.MATCH_PARENT
+        val displayMetrics = context.resources.displayMetrics
+        val screenWidthDp = displayMetrics.widthPixels / displayMetrics.density
+        width = if (screenWidthDp >= 600) {
+            (400 * displayMetrics.density).toInt()
+        } else {
+            WindowManager.LayoutParams.MATCH_PARENT
+        }
         type = WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY
         format = PixelFormat.TRANSLUCENT
-        gravity = Gravity.BOTTOM
+        gravity = Gravity.BOTTOM or Gravity.CENTER_HORIZONTAL
         dimAmount = 0.3f
         flags = WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS or
             WindowManager.LayoutParams.FLAG_FULLSCREEN or
@@ -84,7 +90,6 @@ class PopupWindow(
         mParams.x = 0
         mParams.y = 0
 
-        mParams.gravity = Gravity.BOTTOM
         mView.setOnClickListener {
             close()
         }