var activity

AndroidManifest.xml

@@ -19,7 +19,9 @@
 
 		<activity a:name=".CalculatorPreferencesActivity" a:label="@string/c_app_settings"/>
 		<activity a:name=".AboutActivity" a:label="@string/c_about"/>
-		<activity a:name=".CalculatorVarsActivity" a:label="@string/c_vars_and_constants"/>
+		<activity 	a:name=".CalculatorVarsActivity"
+					a:label="@string/c_vars_and_constants"
+					a:configChanges="orientation|keyboardHidden" />
 
     </application>
 </manifest>

res/layout/var_edit.xml

@@ -6,41 +6,52 @@
   ~ or visit http://se.solovyev.org
   -->
 
-<LinearLayout xmlns:a="http://schemas.android.com/apk/res/android"
+<ScrollView xmlns:a="http://schemas.android.com/apk/res/android"
-			  a:id="@+id/var_edit"
-			  a:orientation="vertical"
 			a:layout_width="match_parent"
 			a:layout_height="match_parent">
 
+	<LinearLayout xmlns:a="http://schemas.android.com/apk/res/android"
+				  a:id="@+id/var_edit"
+				  a:orientation="vertical"
+				  a:layout_width="match_parent"
+				  a:layout_height="match_parent"
+				  a:scrollbars="vertical"
+				  a:scrollbarAlwaysDrawVerticalTrack="true">
+
 		<TextView a:layout_height="match_parent"
 				  a:layout_width="wrap_content"
-			  a:text="Name"/>
+				  a:padding="6dp"
+				  a:text="@string/c_var_name"/>
 
 		<EditText a:id="@+id/var_edit_name"
 				  a:layout_width="match_parent"
-			  a:layout_height="match_parent"
+				  a:layout_height="wrap_content"
 				  a:textSize="20dp">
 		</EditText>
 
 		<TextView a:layout_height="match_parent"
 				  a:layout_width="wrap_content"
-			  a:text="Value"/>
+				  a:padding="6dp"
+				  a:text="@string/c_var_value"/>
 
 		<EditText a:id="@+id/var_edit_value"
 				  a:layout_width="match_parent"
-			  a:layout_height="match_parent"
+				  a:layout_height="wrap_content"
 				  a:inputType="number"
 				  a:textSize="20dp">
 		</EditText>
 
 		<TextView a:layout_height="match_parent"
 				  a:layout_width="wrap_content"
-			  a:text="Description"/>
+				  a:padding="6dp"
+				  a:text="@string/c_var_description"/>
 
 		<EditText a:id="@+id/var_edit_description"
 				  a:layout_width="match_parent"
-			  a:layout_height="match_parent"
+				  a:layout_height="wrap_content"
 				  a:textSize="20dp">
 		</EditText>
 
-</LinearLayout>
+	</LinearLayout>
+
+</ScrollView>

res/values/strings.xml

@@ -37,4 +37,14 @@
 	<string name="c_add">Add</string>
 	<string name="c_cancel">Cancel</string>
 	<string name="c_save">Save</string>
+	<string name="c_remove">Remove</string>
+	<string name="c_yes">Yes</string>
+	<string name="c_no">No</string>
+	<string name="c_var_removal_confirmation">Removal confirmation</string>
+	<string name="c_var_removal_confirmation_question">Do you really want to delete \'%s\' variable?</string>
+	<string name="c_var_name">Name</string>
+	<string name="c_var_value">value</string>
+	<string name="c_var_description">Description</string>
+	<string name="c_var_create_var">Create variable</string>
+	<string name="c_var_edit_var">Edit variable</string>
 </resources>

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

@@ -64,7 +64,7 @@ public class CalculatorVarsActivity extends ListActivity {
 
 	}
 
-	private void createEditVariableDialog(@Nullable Var var, @Nullable String name, @Nullable String value, @Nullable String description) {
+	private void createEditVariableDialog(@Nullable final Var var, @Nullable final String name, @Nullable final String value, @Nullable final String description) {
 		if (var == null || !var.isSystem()) {
 
 			final LayoutInflater layoutInflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
@@ -86,16 +86,29 @@ public class CalculatorVarsActivity extends ListActivity {
 				varBuilder = new Var.Builder();
 			}
 
-			new AlertDialog.Builder(this)
+			final AlertDialog.Builder builder = new AlertDialog.Builder(this)
 					.setCancelable(true)
-					.setNegativeButton(getString(R.string.c_cancel), new DialogInterface.OnClickListener() {
+					.setNegativeButton(R.string.c_cancel, null)
+					.setPositiveButton(R.string.c_save, new VarEditorSaver(varBuilder, var, editView))
+					.setView(editView);
+
+			if ( var != null ) {
+				// EDIT mode
+
+				builder.setTitle(R.string.c_var_edit_var);
+				builder.setNeutralButton(R.string.c_remove, new VarEditorRemover(var, new DialogInterface.OnClickListener() {
 					@Override
 					public void onClick(DialogInterface dialog, int which) {
-							// do nothing
+						createEditVariableDialog(var, name, value, description);
 					}
-					})
+				}));
-					.setPositiveButton(getString(R.string.c_save), new VarEditorSaver(varBuilder, var, editView))
+			} else {
-					.setView(editView).create().show();
+				// CREATE mode
+
+				builder.setTitle(R.string.c_var_create_var);
+			}
+
+			builder.create().show();
 		} else {
 			Toast.makeText(this, "System variable cannot be changed!", Toast.LENGTH_LONG).show();
 		}
@@ -234,4 +247,48 @@ public class CalculatorVarsActivity extends ListActivity {
 
 		return result;
 	}
+
+	private class VarEditorRemover implements DialogInterface.OnClickListener {
+
+		@NotNull
+		private final Var var;
+
+		@Nullable
+		private final DialogInterface.OnClickListener callbackOnCancel;
+
+		private final boolean confirmed;
+
+		public VarEditorRemover(@NotNull Var var, @Nullable DialogInterface.OnClickListener callbackOnCancel) {
+			this(var, callbackOnCancel, false);
+		}
+
+		public VarEditorRemover(@NotNull Var var, @Nullable DialogInterface.OnClickListener callbackOnCancel, boolean confirmed) {
+			this.var = var;
+			this.callbackOnCancel = callbackOnCancel;
+			this.confirmed = confirmed;
+		}
+
+		@Override
+		public void onClick(DialogInterface dialog, int which) {
+			if (!confirmed) {
+				final TextView question = new TextView(CalculatorVarsActivity.this);
+				question.setText(String.format(getString(R.string.c_var_removal_confirmation_question), var.getName()));
+				question.setPadding(6, 6, 6, 6);
+				final AlertDialog.Builder builder = new AlertDialog.Builder(CalculatorVarsActivity.this)
+						.setCancelable(true)
+						.setView(question)
+						.setTitle(R.string.c_var_removal_confirmation)
+						.setNegativeButton(R.string.c_no, callbackOnCancel)
+						.setPositiveButton(R.string.c_yes, new VarEditorRemover(var, callbackOnCancel, true));
+
+				builder.create().show();
+			} else {
+				adapter.remove(var);
+				final VarsRegister varsRegister = CalculatorModel.getInstance().getVarsRegister();
+				varsRegister.remove(var);
+				varsRegister.save(CalculatorVarsActivity.this);
+				CalculatorVarsActivity.this.adapter.notifyDataSetChanged();
+			}
+		}
+	}
 }

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

@@ -56,6 +56,10 @@ public class VarsRegister {
 		return var;
 	}
 
+	public void remove (@NotNull Var var) {
+		this.vars.remove(var);
+	}
+
 	@Nullable
 	public Var getVar(@NotNull final String name) {
 		return CollectionsUtils.get(vars, new Finder<Var>() {