diff --git a/.idea/encodings.xml b/.idea/encodings.xml
index d11d9c1..05df718 100644
--- a/.idea/encodings.xml
+++ b/.idea/encodings.xml
@@ -3,5 +3,6 @@
   <component name="Encoding">
     <file url="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/gtask/remote/GTaskClient.java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/ui/NotesListActivity.java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/ui/NotesPreferenceActivity.java" charset="GBK" />
   </component>
 </project>
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/AlarmAlertActivity.java b/app/src/main/java/net/micode/notes/ui/AlarmAlertActivity.java
index 85723be..f1c9197 100644
--- a/app/src/main/java/net/micode/notes/ui/AlarmAlertActivity.java
+++ b/app/src/main/java/net/micode/notes/ui/AlarmAlertActivity.java
@@ -30,6 +30,7 @@ import android.net.Uri;
 import android.os.Bundle;
 import android.os.PowerManager;
 import android.provider.Settings;
+import android.support.v7.app.AppCompatActivity;
 import android.view.Window;
 import android.view.WindowManager;
 
@@ -40,7 +41,7 @@ import net.micode.notes.tool.DataUtils;
 import java.io.IOException;
 
 
-public class AlarmAlertActivity extends Activity implements OnClickListener, OnDismissListener {
+public class AlarmAlertActivity extends AppCompatActivity implements OnClickListener, OnDismissListener {
     private long mNoteId;
     private String mSnippet;
     private static final int SNIPPET_PREW_MAX_LEN = 60;
diff --git a/app/src/main/java/net/micode/notes/ui/NoteEditActivity.java b/app/src/main/java/net/micode/notes/ui/NoteEditActivity.java
index 96a9ff8..4eca952 100644
--- a/app/src/main/java/net/micode/notes/ui/NoteEditActivity.java
+++ b/app/src/main/java/net/micode/notes/ui/NoteEditActivity.java
@@ -30,6 +30,7 @@ import android.content.SharedPreferences;
 import android.graphics.Paint;
 import android.os.Bundle;
 import android.preference.PreferenceManager;
+import android.support.v7.app.AppCompatActivity;
 import android.text.Spannable;
 import android.text.SpannableString;
 import android.text.TextUtils;
@@ -72,7 +73,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 
-public class NoteEditActivity extends Activity implements OnClickListener,
+public class NoteEditActivity extends AppCompatActivity implements OnClickListener,
         NoteSettingChangedListener, OnTextViewChangeListener {
     private class HeadViewHolder {
         public TextView tvModified;
@@ -429,8 +430,7 @@ public class NoteEditActivity extends Activity implements OnClickListener,
         int id = v.getId();
         if (id == R.id.btn_set_bg_color) {
             mNoteBgColorSelector.setVisibility(View.VISIBLE);
-            findViewById(sBgSelectorSelectionMap.get(mWorkingNote.getBgColorId())).setVisibility(
-                    -                    View.VISIBLE);
+            findViewById(sBgSelectorSelectionMap.get(mWorkingNote.getBgColorId())).setVisibility(View.VISIBLE);
         } else if (sBgSelectorBtnsMap.containsKey(id)) {
             findViewById(sBgSelectorSelectionMap.get(mWorkingNote.getBgColorId())).setVisibility(
                     View.GONE);
diff --git a/app/src/main/java/net/micode/notes/ui/NoteEditText.java b/app/src/main/java/net/micode/notes/ui/NoteEditText.java
index 2afe2a8..24278b5 100644
--- a/app/src/main/java/net/micode/notes/ui/NoteEditText.java
+++ b/app/src/main/java/net/micode/notes/ui/NoteEditText.java
@@ -37,7 +37,7 @@ import net.micode.notes.R;
 import java.util.HashMap;
 import java.util.Map;
 
-public class NoteEditText extends EditText {
+public class NoteEditText extends android.support.v7.widget.AppCompatEditText {
     private static final String TAG = "NoteEditText";
     private int mIndex;
     private int mSelectionStartBeforeDelete;