preferences + asyn result calculation

src/main/java/org/solovyev/android/calculator/CalculatorView.java

@@ -14,6 +14,7 @@ import bsh.EvalError;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.util.StringUtils;
+import org.solovyev.util.date.MutableObject;
 import org.solovyev.util.math.MathEntityType;
 
 import java.util.Date;
@@ -92,6 +93,9 @@ public class CalculatorView implements CursorControl{
 		}
 	}
 
+	@NotNull
+	private final MutableObject<Runnable> currentRunner = new MutableObject<Runnable>();
+
 	public void doTextOperation(@NotNull TextOperation operation) {
 		final String editorStateBefore = this.editor.getText().toString();
 
@@ -99,9 +103,27 @@ public class CalculatorView implements CursorControl{
 
 		final String editorStateAfter = this.editor.getText().toString();
 		if (!editorStateBefore.equals(editorStateAfter)) {
+
+			currentRunner.setObject(new Runnable() {
+				@Override
+				public void run() {
+					synchronized (currentRunner) {
+						// do only if nothing was post delayed before current instance was posted
+						if (currentRunner.getObject() == this) {
 							// actually nothing shall be logged while text operations are done
 							evaluate(editorStateAfter, false);
 
+							if (history.isRedoAvailable()) {
+								history.redo(getCurrentHistoryState());
+							}
+							saveHistoryState();
+						}
+					}
+				}
+			});
+
+			new Handler().postDelayed(currentRunner.getObject(), 500);
+
 			saveHistoryState();
 		}
 	}
@@ -112,9 +134,6 @@ public class CalculatorView implements CursorControl{
 			final TextView localDisplay = display;
 			final Activity localActivity = activity;
 
-			new Handler().post(new Runnable() {
-				@Override
-				public void run() {
 			try {
 				localDisplay.setText(calculator.evaluate(JsclOperation.numeric, expression));
 			} catch (EvalError evalError) {
@@ -123,8 +142,6 @@ public class CalculatorView implements CursorControl{
 				}
 			}
 		}
-			});
-		}
 	}
 
 	public void clear() {

src/main/java/org/solovyev/util/date/MutableObject.java

@@ -0,0 +1,26 @@
+package org.solovyev.util.date;
+
+/**
+ * User: serso
+ * Date: 9/13/11
+ * Time: 6:46 PM
+ */
+public class MutableObject<T> {
+
+	private T object;
+
+	public MutableObject() {
+	}
+
+	public MutableObject(T object) {
+		this.object = object;
+	}
+
+	public T getObject() {
+		return object;
+	}
+
+	public void setObject(T object) {
+		this.object = object;
+	}
+}