Added colors and improved menu.

Author: gianluca-nitti

app/src/main/java/com/github/gianlucanitti/expreval/ExprEval.java

@@ -2,9 +2,11 @@
 
 import android.app.AlertDialog;
 import android.content.DialogInterface;
+import android.graphics.Color;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.support.v7.widget.Toolbar;
+import android.text.Html;
 import android.text.method.ScrollingMovementMethod;
 import android.view.Menu;
 import android.view.MenuItem;
@@ -15,10 +17,10 @@
 import com.github.gianlucanitti.javaexpreval.ExpressionContext;
 import com.github.gianlucanitti.javaexpreval.InteractiveExpressionContext;
 import com.github.gianlucanitti.javaexpreval.NullInputStream;
+import com.github.gianlucanitti.javaexpreval.NullOutputStream;
 
 import java.io.IOException;
 import java.io.StringReader;
-import java.io.StringWriter;
 
 public class ExprEval extends AppCompatActivity implements View.OnClickListener{
 
@@ -28,9 +30,13 @@ public class ExprEval extends AppCompatActivity implements View.OnClickListener{
     private TextView out;
     private Button evalBtn;
 
+    private TextViewWriter inEchoWriter;
     private TextViewWriter outWriter;
+    private TextViewWriter verboseWriter;
+    private TextViewWriter errorWriter;
 
     private ContextDialogFragment ctxDialog;
+    private boolean echoInput = true;
 
     public ExpressionContext getContext(){
         return ctx;
@@ -51,8 +57,11 @@ protected void onCreate(Bundle savedInstanceState) {
         evalBtn = (Button)findViewById(R.id.evalBtn);
         evalBtn.setOnClickListener(this);
         ctxDialog = new ContextDialogFragment();
-        outWriter = new TextViewWriter(out);
-        ctx = new InteractiveExpressionContext(NullInputStream.getReader(), outWriter, outWriter, outWriter, true);
+        inEchoWriter = new TextViewWriter(out, Color.YELLOW);
+        outWriter = new TextViewWriter(out, Color.GREEN);
+        verboseWriter = new TextViewWriter(out, out.getTextColors().getDefaultColor());
+        errorWriter = new TextViewWriter(out, Color.RED);
+        ctx = new InteractiveExpressionContext(NullInputStream.getReader(), outWriter, verboseWriter, errorWriter, true);
         ctx.addObserver(ctxDialog);
         ctxDialog.update(ctx, null);
     }
@@ -88,9 +97,21 @@ public void onClick(DialogInterface dialogInterface, int i) {
             case R.id.action_clearout:
                 out.setText("");
                 return true;
+            case R.id.action_verbose:
+                item.setChecked(!item.isChecked());
+                if(item.isChecked())
+                    ctx.setVerboseOutputWriter(verboseWriter, true);
+                else
+                    ctx.setVerboseOutputWriter(NullOutputStream.getWriter(), true);
+                return true;
+            case R.id.action_input:
+                item.setChecked(!item.isChecked());
+                echoInput = item.isChecked();
+                return true;
             case R.id.action_help:
-                new AlertDialog.Builder(this).setMessage("In the input box you can type expressions, variable or function assignments (like \"a=5\" or \"log(x,b)=log(x)/log(b)\") and commands. " +
-                    "The available commands are \"help\", \"context\", \"clear\" and \"exit\". Type \"help\" in the input box for more detailed instructions. ").show();
+                new AlertDialog.Builder(this).setMessage(Html.fromHtml("In the input box you can type expressions, variable or function assignments (like \"a=5\" or \"log(x,b)=log(x)/log(b)\") and commands. " +
+                    "The available commands are \"help\", \"context\", \"clear\" and \"exit\". Type \"help\" in the input box for more detailed instructions. In the output box, results are shown in <font color=\"green\">green</font> and errors in <font color=\"red\">red</font>. " +
+                    "Evaluation steps are shown in default color, and the input is echoed in <font color=\"yellow\">yellow</font> (both can be disabled from the menu).")).show();
                 return true;
             default:
                 return super.onOptionsItemSelected(item);
@@ -102,6 +123,10 @@ public void onClick(View view){
         ctx.setInputReader(new StringReader(in.getText().toString()));
         InteractiveExpressionContext.Status status = null;
         try {
+            if(echoInput) {
+                inEchoWriter.write("> " + in.getText().toString() + System.getProperty("line.separator"));
+                inEchoWriter.flush();
+            }
             status = ctx.update();
         }catch(IOException ex){}
         in.getText().clear();

app/src/main/java/com/github/gianlucanitti/expreval/TextViewWriter.java

@@ -1,6 +1,8 @@
 package com.github.gianlucanitti.expreval;
 
 import android.support.annotation.NonNull;
+import android.text.SpannableString;
+import android.text.style.ForegroundColorSpan;
 import android.widget.TextView;
 
 import java.io.IOException;
@@ -10,9 +12,11 @@ public class TextViewWriter extends Writer {
 
     private StringBuilder buffer;
     private TextView v;
+    private int color;
 
-    public TextViewWriter(TextView target){
+    public TextViewWriter(TextView target, int c){
         v = target;
+        color = c;
         buffer = new StringBuilder();
     }
 
@@ -23,7 +27,9 @@ public void close() throws IOException {
 
     @Override
     public void flush() throws IOException {
-        v.append(buffer.toString());
+        SpannableString s = new SpannableString(buffer.toString());
+        s.setSpan(new ForegroundColorSpan(color), 0, s.length(), 0);
+        v.append(s);
         buffer = new StringBuilder();
     }
 

app/src/main/res/menu/mainmenu.xml

@@ -13,6 +13,18 @@
           android:title="Clear output"
           tools:showAsAction="never"/>
 
+    <item android:id="@+id/action_verbose"
+          android:title="Show steps"
+          android:checkable="true"
+          android:checked="true"
+          tools:showAsAction="never"/>
+
+    <item android:id="@+id/action_input"
+          android:title="Echo input"
+          android:checkable="true"
+          android:checked="true"
+          tools:showAsAction="never"/>
+
     <item android:id="@+id/action_help"
           android:title="Help"
           tools:showAsAction="never"/>