draw tab

Author: tranleduy2000

libeditor/src/main/java/com/duy/ide/editor/text/style/TabSpan.java

@@ -0,0 +1,54 @@
+/*
+ *  Copyright (C)  2018  Duy Tran Le
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.duy.ide.editor.text.style;
+
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.text.style.ReplacementSpan;
+
+import com.duy.ide.editor.text.LayoutContext;
+
+public class TabSpan extends ReplacementSpan {
+    private final int whiteSpaceColor;
+    private final int tabWidth;
+    private boolean isShowWhiteSpace;
+
+    public TabSpan(LayoutContext layoutContext, int tabWidth) {
+        this.whiteSpaceColor = layoutContext.whiteSpaceColor;
+        this.isShowWhiteSpace = layoutContext.isShowWhiteSpace;
+        this.tabWidth = tabWidth;
+    }
+
+    @Override
+    public int getSize(@NonNull Paint paint, CharSequence text, int start, int end, @Nullable Paint.FontMetricsInt fm) {
+        return tabWidth;
+    }
+
+    @Override
+    public void draw(@NonNull Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, @NonNull Paint paint) {
+        if (isShowWhiteSpace) {
+            paint.set(paint);
+            paint.setColor(whiteSpaceColor);
+            paint.setStrokeWidth(2f);
+            paint.setStyle(Paint.Style.FILL);
+            canvas.drawLine(x, y, x + tabWidth - tabWidth / 10f, y, paint);
+        }
+    }
+}

libeditor/src/main/java/com/duy/ide/editor/view/HighlightEditorView.java

@@ -24,11 +24,14 @@
 import android.graphics.Typeface;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.text.Editable;
 import android.text.InputFilter;
 import android.text.InputType;
 import android.text.Layout;
+import android.text.Spannable;
 import android.text.Spanned;
 import android.text.TextPaint;
+import android.text.TextWatcher;
 import android.util.AttributeSet;
 import android.util.TypedValue;
 import android.view.inputmethod.EditorInfo;
@@ -37,6 +40,7 @@
 import com.duy.ide.editor.text.LayoutContext;
 import com.duy.ide.editor.text.LineManager;
 import com.duy.ide.editor.text.TextLineNumber;
+import com.duy.ide.editor.text.style.TabSpan;
 import com.duy.ide.editor.theme.model.EditorTheme;
 import com.jecelyin.common.utils.ReflectionUtil;
 import com.jecelyin.common.utils.SysUtils;
@@ -46,7 +50,8 @@
 import java.util.List;
 
 public abstract class HighlightEditorView extends android.support.v7.widget.AppCompatEditText
-        implements IEditAreaView, SharedPreferences.OnSharedPreferenceChangeListener {
+        implements IEditAreaView, SharedPreferences.OnSharedPreferenceChangeListener,
+        TextWatcher {
     private static final String TAG = "EditAreaView2";
     private final LayoutContext mLayoutContext = new LayoutContext();
     protected Preferences mPreferences;
@@ -68,6 +73,7 @@ public abstract class HighlightEditorView extends android.support.v7.widget.AppC
      */
     private boolean mNeedUpdateLineNumber = false;
     private boolean mIsAutoIndent = true;
+    private int mTabWidth = 3;
 
     public HighlightEditorView(Context context) {
         super(context);
@@ -123,6 +129,7 @@ private void init(Context context) {
         onSharedPreferenceChanged(null, Preferences.KEY_AUTO_CAPITALIZE);
 
         initAutoIndent();
+        addTextChangedListener(this);
     }
 
     private void initAutoIndent() {
@@ -213,7 +220,6 @@ private void setCursorColor(int caretColor) {
         }
     }
 
-
     @Override
     public void scrollToLine(int line) {
 
@@ -241,7 +247,6 @@ public void setInitLineNumber(int lineNumber) {
         updateLineNumberCount(0);
     }
 
-
     private void drawLineNumber(Canvas canvas) {
         if (!mLayoutContext.getPreferences().isShowLineNumber()) {
             return;
@@ -321,7 +326,6 @@ public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, Strin
         }
     }
 
-
     @Override
     public void setTextSize(int unit, float size) {
         super.setTextSize(unit, size);
@@ -330,9 +334,30 @@ public void setTextSize(int unit, float size) {
     }
 
     @Override
-    protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
-        super.onTextChanged(text, start, lengthBefore, lengthAfter);
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+
+    }
+
+    @Override
+    public void afterTextChanged(Editable s) {
+
+    }
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int before, int count) {
         updateLineNumberCount(start);
+        if (s instanceof Spannable) {
+            applyTabWidth((Spannable) s, start, start + count - 1);
+        }
+    }
+
+    public void applyTabWidth(Spannable text, int start, int end) {
+        for (int index = start; index <= end; index++) {
+            if (text.charAt(index) == '\t') {
+                text.setSpan(new TabSpan(getLayoutContext(), mTabWidth),
+                        index, index + 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+            }
+        }
     }
 
     /**
@@ -342,6 +367,7 @@ private void updateTabChar() {
         if (DLog.DEBUG) DLog.d(TAG, "updateTabChar() called");
         float spaceWidth = getPaint().measureText(" ");
         float tabWidth = spaceWidth * (mPreferences == null ? 4 : mPreferences.getTabSize());
+        mTabWidth = (int) tabWidth;
         try {
             Field tabIncrement = ReflectionUtil.getField(Layout.class,
                     "TAB_INCREMENT", true);