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AmrDeveloperAmrDeveloper
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Add Simple Undo Redo feature in the example app
1 parent dcf1443 commit 24f612f

6 files changed

Lines changed: 242 additions & 7 deletions

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‎app/src/main/java/com/amrdeveloper/codeviewlibrary/MainActivity.java‎

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Original file line numberDiff line numberDiff line change
@@ -20,6 +20,7 @@
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import com.amrdeveloper.codeview.CodeView;
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import com.amrdeveloper.codeviewlibrary.plugin.CommentManager;
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import com.amrdeveloper.codeviewlibrary.plugin.SourcePositionListener;
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import com.amrdeveloper.codeviewlibrary.plugin.UndoRedoManager;
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import com.amrdeveloper.codeviewlibrary.syntax.ThemeName;
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import com.amrdeveloper.codeviewlibrary.syntax.LanguageName;
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import com.amrdeveloper.codeviewlibrary.syntax.LanguageManager;
@@ -34,6 +35,7 @@ public class MainActivity extends AppCompatActivity {
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private CodeView codeView;
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private LanguageManager languageManager;
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private CommentManager commentManager;
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private UndoRedoManager undoRedoManager;
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private TextView languageNameText;
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private TextView sourcePositionText;
@@ -124,6 +126,9 @@ private void configCodeViewPlugins() {
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commentManager = new CommentManager(codeView);
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configCommentInfo();
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undoRedoManager = new UndoRedoManager(codeView);
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undoRedoManager.connect();
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languageNameText = findViewById(R.id.language_name_txt);
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configLanguageName();
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@@ -165,6 +170,8 @@ public boolean onOptionsItemSelected(@NonNull MenuItem item) {
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else if (menuItemId == R.id.comment) commentManager.commentSelected();
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else if (menuItemId == R.id.un_comment) commentManager.unCommentSelected();
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else if (menuItemId == R.id.clearText) codeView.setText("");
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else if (menuItemId == R.id.undo) undoRedoManager.undo();
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else if (menuItemId == R.id.redo) undoRedoManager.redo();
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return super.onOptionsItemSelected(item);
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}

‎app/src/main/java/com/amrdeveloper/codeviewlibrary/plugin/UndoRedoManager.java‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,201 @@
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package com.amrdeveloper.codeviewlibrary.plugin;
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import android.text.Editable;
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import android.text.Selection;
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import android.text.TextUtils;
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import android.text.TextWatcher;
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import android.text.style.UnderlineSpan;
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import android.widget.TextView;
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import java.util.LinkedList;
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public class UndoRedoManager {
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private final TextView textView;
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private final EditHistory editHistory;
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private final TextChangeWatcher textChangeWatcher;
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private boolean isUndoOrRedo = false;
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public UndoRedoManager(TextView textView) {
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this.textView = textView;
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editHistory = new EditHistory();
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textChangeWatcher = new TextChangeWatcher();
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}
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public void undo() {
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EditNode edit = editHistory.getPrevious();
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if (edit == null) return;
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Editable text = textView.getEditableText();
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int start = edit.start;
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int end = start + (edit.after != null ? edit.after.length() : 0);
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isUndoOrRedo = true;
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text.replace(start, end, edit.before);
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isUndoOrRedo = false;
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UnderlineSpan[] underlineSpans = text.getSpans(0, text.length(), UnderlineSpan.class);
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for (Object span : underlineSpans) text.removeSpan(span);
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Selection.setSelection(text, edit.before == null ? start : (start + edit.before.length()));
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}
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public void redo() {
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EditNode edit = editHistory.getNext();
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if (edit == null) return;
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Editable text = textView.getEditableText();
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int start = edit.start;
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int end = start + (edit.before != null ? edit.before.length() : 0);
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isUndoOrRedo = true;
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text.replace(start, end, edit.after);
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isUndoOrRedo = false;
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UnderlineSpan[] underlineSpans = text.getSpans(0, text.length(), UnderlineSpan.class);
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for (Object span : underlineSpans) text.removeSpan(span);
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Selection.setSelection(text, edit.after == null ? start : (start + edit.after.length()));
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}
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public void connect() {
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textView.addTextChangedListener(textChangeWatcher);
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}
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public void disconnect() {
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textView.removeTextChangedListener(textChangeWatcher);
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}
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public void setMaxHistorySize(int maxSize) {
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editHistory.setMaxHistorySize(maxSize);
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}
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public void clearHistory() {
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editHistory.clear();
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}
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public boolean canUndo() {
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return editHistory.position > 0;
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}
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public boolean canRedo() {
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return editHistory.position < editHistory.historyList.size();
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}
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private static final class EditHistory {
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private int position = 0;
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private int maxHistorySize = -1;
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private final LinkedList<EditNode> historyList = new LinkedList<>();
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private void clear() {
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position = 0;
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historyList.clear();
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}
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private void add(EditNode item) {
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while (historyList.size() > position) historyList.removeLast();
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historyList.add(item);
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position++;
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if (maxHistorySize >= 0) trimHistory();
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}
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private void setMaxHistorySize(int maxHistorySize) {
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this.maxHistorySize = maxHistorySize;
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if (this.maxHistorySize >= 0) trimHistory();
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}
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private void trimHistory() {
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while (historyList.size() > maxHistorySize) {
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historyList.removeFirst();
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position--;
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}
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if (position < 0) position = 0;
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}
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private EditNode getCurrent() {
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if (position == 0) return null;
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return historyList.get(position - 1);
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}
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private EditNode getPrevious() {
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if (position == 0) return null;
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position--;
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return historyList.get(position);
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}
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private EditNode getNext() {
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if (position >= historyList.size()) return null;
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EditNode item = historyList.get(position);
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position++;
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return item;
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}
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}
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private static final class EditNode {
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private int start;
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private CharSequence before;
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private CharSequence after;
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public EditNode(int start, CharSequence before, CharSequence after) {
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this.start = start;
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this.before = before;
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this.after = after;
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}
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}
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private enum ActionType {
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INSERT, DELETE, PASTE, NOT_DEF;
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}
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private final class TextChangeWatcher implements TextWatcher {
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private CharSequence beforeChange;
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private CharSequence afterChange;
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private ActionType lastActionType = ActionType.NOT_DEF;
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public void beforeTextChanged(CharSequence s, int start, int count, int after) {
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if (isUndoOrRedo) return;
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beforeChange = s.subSequence(start, start + count);
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}
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public void onTextChanged(CharSequence s, int start, int before, int count) {
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if (isUndoOrRedo) return;
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afterChange = s.subSequence(start, start + count);
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makeBatch(start);
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}
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private void makeBatch(int start) {
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ActionType action = getActionType();
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EditNode currentNode = editHistory.getCurrent();
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if (lastActionType != action || ActionType.PASTE == action || currentNode == null) {
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editHistory.add(new EditNode(start, beforeChange, afterChange));
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} else {
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if (action == ActionType.DELETE) {
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currentNode.start = start;
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currentNode.before = TextUtils.concat(beforeChange, currentNode.before);
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} else {
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currentNode.after = TextUtils.concat(currentNode.after, afterChange);
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}
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}
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lastActionType = action;
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}
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private ActionType getActionType() {
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if (!TextUtils.isEmpty(beforeChange) && TextUtils.isEmpty(afterChange)) {
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return ActionType.DELETE;
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} else if (TextUtils.isEmpty(beforeChange) && !TextUtils.isEmpty(afterChange)) {
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return ActionType.INSERT;
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} else {
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return ActionType.PASTE;
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}
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}
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public void afterTextChanged(Editable s) {
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}
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}
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}

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

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@@ -0,0 +1,5 @@
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<vector android:height="24dp" android:tint="#FFFFFF"
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android:viewportHeight="24" android:viewportWidth="24"
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android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
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<path android:fillColor="@android:color/white" android:pathData="M18.4,10.6C16.55,8.99 14.15,8 11.5,8c-4.65,0 -8.58,3.03 -9.96,7.22L3.9,16c1.05,-3.19 4.05,-5.5 7.6,-5.5 1.95,0 3.73,0.72 5.12,1.88L13,16h9V7l-3.6,3.6z"/>
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</vector>

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

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@@ -0,0 +1,5 @@
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<vector android:height="24dp" android:tint="#FFFFFF"
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android:viewportHeight="24" android:viewportWidth="24"
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android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
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<path android:fillColor="@android:color/white" android:pathData="M12.5,8c-2.65,0 -5.05,0.99 -6.9,2.6L2,7v9h9l-3.62,-3.62c1.39,-1.16 3.16,-1.88 5.12,-1.88 3.54,0 6.55,2.31 7.6,5.5l2.37,-0.78C21.08,11.03 17.15,8 12.5,8z"/>
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</vector>

‎app/src/main/res/menu/menu_main.xml‎

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@@ -1,9 +1,24 @@
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<?xml version="1.0" encoding="utf-8"?>
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<menu xmlns:android="http://schemas.android.com/apk/res/android">
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<menu xmlns:android="http://schemas.android.com/apk/res/android"
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xmlns:app="http://schemas.android.com/apk/res-auto">
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<item
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android:id="@+id/languages"
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android:id="@+id/undo"
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android:icon="@drawable/ic_undo"
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android:title="@string/undo"
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android:orderInCategory="1"
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app:showAsAction="ifRoom" />
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<item
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android:id="@+id/redo"
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android:icon="@drawable/ic_redo"
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android:title="@string/undo"
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android:orderInCategory="2"
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app:showAsAction="ifRoom" />
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<item
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android:id="@+id/languages"
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android:orderInCategory="3"
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android:title="@string/languages">
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<menu>
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<group android:id="@+id/group_languages">
@@ -25,7 +40,7 @@
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<item
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android:id="@+id/themes"
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android:orderInCategory="2"
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android:orderInCategory="4"
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android:title="@string/themes">
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<menu>
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<group android:id="@+id/group_themes">
@@ -49,21 +64,21 @@
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<item
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android:id="@+id/findMenu"
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android:icon="@drawable/ic_find_in_page"
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android:orderInCategory="3"
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android:orderInCategory="5"
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android:title="@string/find_and_replace" />
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<item
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android:id="@+id/comment"
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android:orderInCategory="4"
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android:orderInCategory="6"
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android:title="@string/comment" />
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<item
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android:id="@+id/un_comment"
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android:orderInCategory="5"
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android:orderInCategory="7"
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android:title="@string/uncomment" />
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<item
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android:id="@+id/clearText"
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android:orderInCategory="6"
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android:orderInCategory="8"
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android:title="@string/clear_text" />
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</menu>

‎app/src/main/res/values/strings.xml‎

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@@ -11,6 +11,8 @@
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<string name="clear_text">Clear Text</string>
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<string name="comment">Comment</string>
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<string name="uncomment">UnComment</string>
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<string name="undo">Undo</string>
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<string name="redo">Redo</string>
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<!-- Programming Languages -->
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<string name="languages">Languages</string>

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