#126 Allow insert an operator before selected term: implemented

app/src/main/java/com/mkulesh/micromath/formula/FormulaBase.java

@@ -120,14 +120,6 @@ public FormulaBase(FormulaList formulaList, LinearLayout layout, int termDepth)
      * Primitives
      *--------------------------------------------------------*/
 
-    /**
-     * Procedure checks whether this formula is a root formula
-     */
-    public boolean isRootFormula()
-    {
-        return getBaseType() != BaseType.TERM;
-    }
-
     /**
      * Getter for parent list of formulas
      */
@@ -521,6 +513,18 @@ public boolean enableDetails()
         return false;
     }
 
+    @Override
+    public boolean isRootFormula()
+    {
+        return getBaseType() != BaseType.TERM;
+    }
+
+    @Override
+    public void setInsertBefore(boolean insertBefore)
+    {
+        formulaList.getDocumentSettings().insertBefore = insertBefore;
+    }
+
     /*--------------------------------------------------------*
      * Read/write interface
      *--------------------------------------------------------*/

app/src/main/java/com/mkulesh/micromath/formula/FormulaTerm.java

@@ -376,6 +376,21 @@ protected void initializeMainLayout()
         }
     }
 
+    public TermField getInsertionRefTerm()
+    {
+        if (getTerms().size() == 2)
+        {
+            // put whole text into the term that depends on "insertBefore" flag
+            return formulaRoot.getFormulaList().getDocumentSettings().insertBefore ?
+                    getTerms().get(1) : getTerms().get(0);
+        }
+        else
+        {
+            // put whole text into the first term
+            return getArgumentTerm();
+        }
+    }
+
     protected boolean splitIntoTerms(final String src, final TermTypeIf t, boolean pasteFromClipboard)
     {
         if (src == null || src.isEmpty() || (t != null && t.getLowerCaseName().equals(src.toLowerCase(Locale.ENGLISH))))
@@ -401,8 +416,8 @@ protected boolean splitIntoTerms(final String src, final TermTypeIf t, boolean p
             }
             if (sepPosition < 0)
             {
-                // no separator found: put whole text into the first term
-                final TermField term = getArgumentTerm();
+                // no separator found:
+                final TermField term = getInsertionRefTerm();
                 if (term != null)
                 {
                     term.setText(src);

app/src/main/java/com/mkulesh/micromath/formula/TermField.java

@@ -1028,7 +1028,7 @@ public void addOperatorCode(String code, final Object extPar)
 
         if (isTerm() && !term.getTerms().isEmpty() && savedState != null)
         {
-            final TermField tf = term.getArgumentTerm();
+            final TermField tf = term.getInsertionRefTerm();
             if (tf != null && tf.getEditText() != null && tf.getEditText().isConversionEnabled())
             {
                 tf.readFromBundle(savedState, "savedState");

app/src/main/java/com/mkulesh/micromath/plots/PlotFunction.java

@@ -334,7 +334,7 @@ public boolean onNewTerm(TermField owner, String s, boolean requestFocus)
         }
 
         // create and prepare new function
-        Function2D f = ownerFunc.addNewAfter();
+        Function2D f = ownerFunc.addNewFunction(getFormulaList().getDocumentSettings().insertBefore);
         if (f == null)
         {
             return true;
@@ -708,7 +708,7 @@ private void ensureFunctionsNumber(int number)
         }
         while (functions.size() < number)
         {
-            functions.add(ownerFunc.addNewAfter());
+            functions.add(ownerFunc.addNewFunction(false));
         }
         reIndexTerms();
         updateTextSize();
@@ -803,7 +803,6 @@ private class Function2D implements FunctionIf
 
         private LinearLayout xLayout = null;
         private TermField x = null;
-        private CustomTextView xSeparator = null;
         private LinearLayout yLayout = null;
         private TermField y = null;
         private CustomTextView settingsView = null;
@@ -902,7 +901,7 @@ void initializePrimaryY()
             settingsView.prepare(CustomTextView.SymbolType.HOR_LINE, getFormulaList().getActivity(), PlotFunction.this);
         }
 
-        Function2D addNewAfter()
+        Function2D addNewFunction(final boolean insertBefore)
         {
             int xViewIndex = ViewUtils.getViewIndex(xDataLayout, xLayout);
             int yViewIndex = ViewUtils.getViewIndex(yDataLayout, settingsView);
@@ -920,8 +919,17 @@ Function2D addNewAfter()
                 final String tag = (String) t.getTag();
                 if (Y_FUNCTION_TAG.equals(tag) && t instanceof LinearLayout)
                 {
-                    f.initializeY((LinearLayout) t, terms.indexOf(y) + 1);
-                    yDataLayout.addView(t, ++yViewIndex);
+                    final int idx = insertBefore ? terms.indexOf(y) : terms.indexOf(y) + 1;
+                    f.initializeY((LinearLayout) t, idx);
+                    if (insertBefore)
+                    {
+                        yViewIndex--;
+                    }
+                    else
+                    {
+                        yViewIndex++;
+                    }
+                    yDataLayout.addView(t, yViewIndex);
                 }
                 else if (Y_SETTINGS_TAG.equals(tag) && t instanceof CustomTextView)
                 {
@@ -932,14 +940,23 @@ else if (Y_SETTINGS_TAG.equals(tag) && t instanceof CustomTextView)
                 }
                 else if (X_SEPARATOR_TAG.equals(tag) && t instanceof CustomTextView)
                 {
-                    f.xSeparator = (CustomTextView) t;
-                    f.xSeparator.setText(getContext().getResources().getString(R.string.formula_term_separator));
-                    xDataLayout.addView(t, ++xViewIndex);
+                    final CustomTextView xSeparator = (CustomTextView) t;
+                    xSeparator.setText(getContext().getResources().getString(R.string.formula_term_separator));
+                    if (!insertBefore)
+                    {
+                        xViewIndex++;
+                    }
+                    xDataLayout.addView(t, xViewIndex);
                 }
                 else if (X_FUNCTION_TAG.equals(tag) && t instanceof LinearLayout)
                 {
-                    f.initializeX((LinearLayout) t, terms.indexOf(x) + 1);
-                    xDataLayout.addView(t, ++xViewIndex);
+                    final int idx = insertBefore ? terms.indexOf(x) : terms.indexOf(x) + 1;
+                    f.initializeX((LinearLayout) t, idx);
+                    if (!insertBefore)
+                    {
+                        xViewIndex++;
+                    }
+                    xDataLayout.addView(t, xViewIndex);
                 }
             }
             return f;
@@ -949,18 +966,22 @@ void erase()
         {
             terms.remove(x);
             terms.remove(y);
-            xDataLayout.removeView(xLayout);
             removeSeparator();
+            xDataLayout.removeView(xLayout);
             yDataLayout.removeView(settingsView);
             yDataLayout.removeView(yLayout);
         }
 
         void removeSeparator()
         {
-            if (xSeparator != null)
+            for (int i = 1; i < xDataLayout.getChildCount(); i++)
             {
-                xDataLayout.removeView(xSeparator);
-                xSeparator = null;
+                if (xDataLayout.getChildAt(i) == xLayout &&
+                        X_SEPARATOR_TAG.equals(xDataLayout.getChildAt(i - 1).getTag()))
+                {
+                    xDataLayout.removeViewAt(i - 1);
+                    break;
+                }
             }
         }
 

app/src/main/java/com/mkulesh/micromath/properties/DocumentProperties.java

@@ -75,6 +75,9 @@ public class DocumentProperties
     private ScaledDimensions scaledDimensions = null;
     public boolean redefineAllowed = true;
 
+    // flag that controls term insertion mode: not saved in state, set from the context menu
+    public boolean insertBefore = false;
+
     /**
      * Default constructor
      */

app/src/main/java/com/mkulesh/micromath/utils/ViewUtils.java

@@ -248,7 +248,9 @@ public static void invalidateLayout(View v, final LinearLayout l)
     public static void updateMenuIconColor(Context context, MenuItem m)
     {
         CompatUtils.setDrawableColorAttr(context, m.getIcon(),
-                m.isEnabled() ? R.attr.colorMicroMathIcon : R.attr.colorPrimaryDark);
+                m.isEnabled() ?
+                        (m.isChecked() ? R.attr.colorAccent : R.attr.colorMicroMathIcon)
+                        : R.attr.colorPrimaryDark);
     }
 
     /**

app/src/main/java/com/mkulesh/micromath/widgets/ContextMenuHandler.java

@@ -20,6 +20,8 @@
 import android.view.MenuItem;
 import android.view.View;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.appcompat.view.ActionMode;
 
@@ -33,6 +35,7 @@ public class ContextMenuHandler
 {
     enum Type
     {
+        INSERT_BEFORE(R.id.context_menu_insert_before),
         EXPAND(R.id.context_menu_expand),
         CUT(R.id.context_menu_cut),
         COPY(R.id.context_menu_copy),
@@ -55,6 +58,7 @@ int getResId()
     private final Context context;
     private FormulaChangeIf formulaChangeIf = null;
     private androidx.appcompat.view.ActionMode actionMode = null;
+    private Menu contextMenu = null;
     private View actionModeOwner = null;
 
     public ContextMenuHandler(Context context)
@@ -68,6 +72,7 @@ public ContextMenuHandler(Context context)
 
     public void initialize(TypedArray a)
     {
+        enabled[Type.INSERT_BEFORE.ordinal()] = a.getBoolean(R.styleable.CustomViewExtension_contextMenuInsertBefore, true);
         enabled[Type.EXPAND.ordinal()] = a.getBoolean(R.styleable.CustomViewExtension_contextMenuExpand, true);
         enabled[Type.CUT.ordinal()] = a.getBoolean(R.styleable.CustomViewExtension_contextMenuCut, true);
         enabled[Type.COPY.ordinal()] = a.getBoolean(R.styleable.CustomViewExtension_contextMenuCopy, true);
@@ -115,6 +120,7 @@ public boolean onCreateActionMode(ActionMode mode, Menu menu)
         @Override
         public boolean onPrepareActionMode(ActionMode mode, Menu menu)
         {
+            contextMenu = menu;
             return false; // Return false if nothing is done
         }
 
@@ -124,7 +130,7 @@ public boolean onActionItemClicked(ActionMode mode, MenuItem item)
         {
             if (formulaChangeIf != null)
             {
-                if (processMenu(item.getItemId()))
+                if (processMenu(item))
                 {
                     mode.finish();
                 }
@@ -137,9 +143,11 @@ public boolean onActionItemClicked(ActionMode mode, MenuItem item)
         public void onDestroyActionMode(ActionMode mode)
         {
             actionMode = null;
+            contextMenu = null;
             if (formulaChangeIf != null)
             {
                 formulaChangeIf.finishActionMode(actionModeOwner);
+                formulaChangeIf.setInsertBefore(false);
             }
         }
     };
@@ -148,6 +156,7 @@ public void startActionMode(AppCompatActivity activity, View actionModeOwner, Fo
     {
         this.actionModeOwner = actionModeOwner;
         this.formulaChangeIf = formulaChangeIf;
+        formulaChangeIf.setInsertBefore(false);
 
         ArrayList<View> list = null;
         if (this.actionModeOwner != null && this.actionModeOwner instanceof CustomEditText)
@@ -166,10 +175,26 @@ public void startActionMode(AppCompatActivity activity, View actionModeOwner, Fo
         actionMode = activity.startSupportActionMode(actionModeCallback);
     }
 
-    private boolean processMenu(int itemId)
+    @Nullable MenuItem getMenuItem(Type t)
     {
-        switch (itemId)
+        return contextMenu != null ? contextMenu.findItem(t.getResId()) : null;
+    }
+
+    private boolean processMenu(final @NonNull MenuItem item)
+    {
+        switch (item.getItemId())
+        {
+        case R.id.context_menu_insert_before:
         {
+            final MenuItem m = getMenuItem(Type.INSERT_BEFORE);
+            if (m != null)
+            {
+                m.setChecked(!m.isChecked());
+                formulaChangeIf.setInsertBefore(m.isChecked());
+                ViewUtils.updateMenuIconColor(context, m);
+            }
+            return false;
+        }
         case R.id.context_menu_expand:
             FormulaChangeIf newIf = formulaChangeIf.onExpandSelection(actionModeOwner);
             if (newIf != null)
@@ -178,6 +203,18 @@ private boolean processMenu(int itemId)
                 formulaChangeIf.onTermSelection(null, true, null);
                 actionModeOwner = null;
             }
+            else
+            {
+                item.setVisible(false);
+            }
+            if (newIf == null || newIf.isRootFormula())
+            {
+                final MenuItem m = getMenuItem(Type.INSERT_BEFORE);
+                if (m != null)
+                {
+                    m.setVisible(false);
+                }
+            }
             return false;
         case R.id.context_menu_cut:
             if (actionModeOwner != null && actionModeOwner instanceof CustomEditText)

app/src/main/java/com/mkulesh/micromath/widgets/FormulaChangeIf.java

@@ -85,4 +85,14 @@ public interface FormulaChangeIf
      * Procedure returns whether the object details view is enabled for this formula
      */
     boolean enableDetails();
+
+    /**
+     * Procedure checks whether this formula is a root formula
+     */
+    boolean isRootFormula();
+
+    /**
+     * Procedure sets the flag that a new term shall be added before existing term
+     */
+    void setInsertBefore(boolean insertBefore);
 }

app/src/main/res/layout/formula_equation.xml

@@ -22,13 +22,15 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="@string/formula_left_term_key"
+        micromath:contextMenuInsertBefore="false"
         micromath:equationName="true" />
 
     <com.mkulesh.micromath.widgets.CustomTextView
         android:id="@+id/formula_equation_assign"
         style="@style/FormulaTextViewStyle"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
+        micromath:contextMenuInsertBefore="false"
         android:text="@string/formula_assign_definition" />
 
     <com.mkulesh.micromath.widgets.CustomEditText

app/src/main/res/layout/formula_result.xml

@@ -36,6 +36,7 @@
         style="@style/FormulaTextViewStyle"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
+        micromath:contextMenuInsertBefore="false"
         android:text="@string/formula_result_definition" />
 
     <com.mkulesh.micromath.widgets.CustomTextView

app/src/main/res/layout/image_fragment.xml

@@ -23,6 +23,7 @@
         android:layout_height="100dp"
         android:maxLines="9999"
         android:text="@string/image_fragment_text"
+        micromath:contextMenuInsertBefore="false"
         micromath:contextMenuCopy="true"
         micromath:contextMenuCut="true"
         micromath:contextMenuExpand="true"