Experiment: spell check from style toolbar

app/src/main/java/eu/faircode/email/StyleHelper.java

@@ -26,6 +26,7 @@ import android.content.SharedPreferences;
 import android.graphics.Color;
 import android.graphics.Typeface;
 import android.os.Build;
+import android.os.Bundle;
 import android.text.Editable;
 import android.text.Layout;
 import android.text.NoCopySpan;
@@ -107,6 +108,7 @@ public class StyleHelper {
             R.id.menu_style_superscript,
             R.id.menu_style_strikethrough,
             R.id.menu_style_insert_line,
+            R.id.menu_style_spell_check,
             R.id.menu_style_password,
             R.id.menu_style_code,
             R.id.menu_style_clear
@@ -132,7 +134,11 @@ public class StyleHelper {
 
             v.setOnClickListener(styleListener);
 
-            if (id == R.id.menu_style_password)
+            if (id == R.id.menu_style_spell_check)
+                v.setVisibility(
+                        BuildConfig.DEBUG && LanguageTool.isEnabled(v.getContext())
+                                ? View.VISIBLE : View.GONE);
+            else if (id == R.id.menu_style_password)
                 v.setVisibility(
                         !BuildConfig.PLAY_STORE_RELEASE && Build.VERSION.SDK_INT >= Build.VERSION_CODES.O
                                 ? View.VISIBLE : View.GONE);
@@ -376,6 +382,15 @@ public class StyleHelper {
                 end = tmp;
             }
 
+            if (start == end &&
+                    itemId == R.id.menu_style_spell_check) {
+                Pair<Integer, Integer> paragraph = getParagraph(etBody);
+                if (paragraph == null)
+                    return false;
+                start = paragraph.first;
+                end = paragraph.second;
+            }
+
             if (start == end &&
                     itemId != R.id.menu_link &&
                     itemId != R.id.menu_clear &&
@@ -428,6 +443,8 @@ public class StyleHelper {
                     return setStrikeThrough(etBody, start, end, false);
                 else if (itemId == R.id.menu_style_insert_line)
                     return setLine(etBody, end);
+                else if (itemId == R.id.menu_style_spell_check)
+                    return spellCheck(owner, etBody, start, end);
                 else if (itemId == R.id.menu_style_password)
                     return setPassword(owner, etBody, start, end);
                 else if (itemId == R.id.menu_style_code) {
@@ -1226,6 +1243,53 @@ public class StyleHelper {
         return true;
     }
 
+    static boolean spellCheck(LifecycleOwner owner, EditText etBody, int start, int end) {
+        Log.breadcrumb("style", "action", "spell");
+
+        etBody.setSelection(end);
+
+        final Context context = etBody.getContext();
+
+        Bundle args = new Bundle();
+        args.putCharSequence("text", etBody.getText().subSequence(start, end));
+
+        new SimpleTask<List<LanguageTool.Suggestion>>() {
+            private BackgroundColorSpan highlightSpan = null;
+
+            @Override
+            protected void onPreExecute(Bundle args) {
+                int textColorHighlight = Helper.resolveColor(context, android.R.attr.textColorHighlight);
+                highlightSpan = new BackgroundColorSpan(textColorHighlight);
+                etBody.getText().setSpan(highlightSpan, start, end,
+                        Spanned.SPAN_EXCLUSIVE_EXCLUSIVE | Spanned.SPAN_COMPOSING);
+            }
+
+            @Override
+            protected void onPostExecute(Bundle args) {
+                if (highlightSpan != null)
+                    etBody.getText().removeSpan(highlightSpan);
+            }
+
+            @Override
+            protected List<LanguageTool.Suggestion> onExecute(Context context, Bundle args) throws Throwable {
+                CharSequence text = args.getCharSequence("text");
+                return LanguageTool.getSuggestions(context, text);
+            }
+
+            @Override
+            protected void onExecuted(Bundle args, List<LanguageTool.Suggestion> suggestions) {
+                LanguageTool.applySuggestions(etBody, start, end, suggestions);
+            }
+
+            @Override
+            protected void onException(Bundle args, Throwable ex) {
+                ToastEx.makeText(context, Log.formatThrowable(ex), Toast.LENGTH_LONG).show();
+            }
+        }.execute(context, owner, args, "spell");
+
+        return true;
+    }
+
     static boolean setPassword(LifecycleOwner owner, EditText etBody, int start, int end) {
         Log.breadcrumb("style", "action", "password");
 

app/src/main/res/drawable/twotone_spellcheck_24.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorControlNormal">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M12.45,16h2.09L9.43,3L7.57,3L2.46,16h2.09l1.12,-3h5.64l1.14,3zM6.43,11L8.5,5.48 10.57,11L6.43,11zM21.59,11.59l-8.09,8.09L9.83,16l-1.41,1.41 5.09,5.09L23,13l-1.41,-1.41z"/>
+</vector>

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

@@ -269,6 +269,21 @@
             app:srcCompat="@drawable/twotone_horizontal_rule_24"
             app:tint="@color/action_foreground" />
 
+        <ImageButton
+            android:id="@+id/menu_style_spell_check"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:background="?android:attr/selectableItemBackgroundBorderless"
+            android:contentDescription="@string/title_advanced_lt"
+            android:paddingHorizontal="12dp"
+            android:paddingVertical="6dp"
+            android:scaleType="fitCenter"
+            android:tooltipText="@string/title_advanced_lt"
+            app:layout_constraintStart_toEndOf="@id/menu_style_insert_line"
+            app:layout_constraintTop_toTopOf="parent"
+            app:srcCompat="@drawable/twotone_spellcheck_24"
+            app:tint="@color/action_foreground" />
+
         <ImageButton
             android:id="@+id/menu_style_password"
             android:layout_width="wrap_content"
@@ -279,7 +294,7 @@
             android:paddingVertical="6dp"
             android:scaleType="fitCenter"
             android:tooltipText="@string/title_style_protect"
-            app:layout_constraintStart_toEndOf="@id/menu_style_insert_line"
+            app:layout_constraintStart_toEndOf="@id/menu_style_spell_check"
             app:layout_constraintTop_toTopOf="parent"
             app:srcCompat="@drawable/twotone_lock_24"
             app:tint="@color/action_foreground" />