Clean up some warnings

Change-Id: I417c5b36badb71c3601df3cc6e505592c96fa661
diff --git a/src/com/android/calculator2/CalculatorDisplay.java b/src/com/android/calculator2/CalculatorDisplay.java
index ca31fe9..3a19143 100644
--- a/src/com/android/calculator2/CalculatorDisplay.java
+++ b/src/com/android/calculator2/CalculatorDisplay.java
@@ -84,7 +84,7 @@
         Editable.Factory factory = new CalculatorEditable.Factory(logic);
         for (int i = 0; i < 2; ++i) {
             EditText text = (EditText) getChildAt(i);
-            text.setBackgroundDrawable(null);
+            text.setBackground(null);
             text.setEditableFactory(factory);
             text.setKeyListener(calculatorKeyListener);
             text.setSingleLine();
diff --git a/src/com/android/calculator2/Logic.java b/src/com/android/calculator2/Logic.java
index a91090c..83db577 100644
--- a/src/com/android/calculator2/Logic.java
+++ b/src/com/android/calculator2/Logic.java
@@ -224,7 +224,6 @@
         }
     }
 
-    private static final int ROUND_DIGITS = 1;
     String evaluate(String input) throws SyntaxException {
         if (input.trim().equals("")) {
             return "";
diff --git a/src/com/android/calculator2/PanelSwitcher.java b/src/com/android/calculator2/PanelSwitcher.java
index 6e64259..0933c21 100644
--- a/src/com/android/calculator2/PanelSwitcher.java
+++ b/src/com/android/calculator2/PanelSwitcher.java
@@ -21,7 +21,6 @@
 import android.view.GestureDetector;
 import android.view.MotionEvent;
 import android.view.View;
-import android.view.animation.AccelerateDecelerateInterpolator;
 import android.view.animation.Animation;
 import android.view.animation.Animation.AnimationListener;
 import android.view.animation.TranslateAnimation;