cleaned some code

Author: AndroidDeveloperLB

material_preferences_library/src/main/java/com/lb/material_preferences_library/PreferenceActivity.java

@@ -7,8 +7,6 @@
 import android.preference.Preference;
 import android.preference.PreferenceGroup;
 import android.preference.PreferenceScreen;
-import androidx.annotation.XmlRes;
-import androidx.appcompat.widget.Toolbar;
 import android.util.TypedValue;
 import android.view.View;
 import android.view.ViewGroup;
@@ -17,6 +15,9 @@
 import java.util.Map;
 import java.util.Stack;
 
+import androidx.annotation.XmlRes;
+import androidx.appcompat.widget.Toolbar;
+
 public abstract class PreferenceActivity extends AppCompatPreferenceActivity {
     private Toolbar _toolbar;
 
@@ -45,7 +46,7 @@ protected void onCreate(final Bundle savedInstanceState) {
         addPreferencesFromResource(getPreferencesXmlId());
         final Map<Preference, PreferenceGroup> preferenceToParentMap = buildPreferenceParentTree(this);
         for (PreferenceGroup preferenceGroup : preferenceToParentMap.values())
-            if (preferenceGroup != null && preferenceGroup instanceof PreferenceScreen)
+            if (preferenceGroup instanceof PreferenceScreen)
                 preferenceGroup.setLayoutResource(R.layout.mpl__preference);
         _toolbar.setClickable(true);
         _toolbar.setNavigationIcon(getResIdFromAttribute(this, R.attr.homeAsUpIndicator));

material_preferences_library/src/main/java/com/lb/material_preferences_library/custom_preferences/CheckBoxPreference.java

@@ -67,7 +67,7 @@ public CheckBoxPreference(Context context) {
     protected void onBindView(View view) {
         super.onBindView(view);
         View checkboxView = view.findViewById(android.R.id.checkbox);
-        if (checkboxView != null && checkboxView instanceof Checkable)
+        if (checkboxView instanceof Checkable)
             ((Checkable) checkboxView).setChecked(mChecked);
         syncSummaryView(view);
     }

material_preferences_library/src/main/java/com/lb/material_preferences_library/custom_preferences/SwitchPreference.java

@@ -2,14 +2,15 @@
 
 import android.content.Context;
 import android.content.res.TypedArray;
-import androidx.appcompat.widget.SwitchCompat;
 import android.util.AttributeSet;
 import android.view.View;
 import android.widget.Checkable;
 import android.widget.CompoundButton;
 
 import com.lb.material_preferences_library.R;
 
+import androidx.appcompat.widget.SwitchCompat;
+
 /**
  * A {@link Preference} that provides a two-state toggleable option.
  * <p/>
@@ -114,7 +115,7 @@ protected void init(final Context context, final AttributeSet attrs, final int d
     protected void onBindView(View view) {
         super.onBindView(view);
         View checkableView = view.findViewById(android.R.id.checkbox);
-        if (checkableView != null && checkableView instanceof Checkable) {
+        if (checkableView instanceof Checkable) {
             if (checkableView instanceof SwitchCompat) {
                 final SwitchCompat switchView = (SwitchCompat) checkableView;
                 switchView.setOnCheckedChangeListener(null);

material_preferences_library/src/main/java/com/lb/material_preferences_library/custom_preferences/TwoStatePreference.java

@@ -79,7 +79,7 @@ public boolean isChecked() {
 
     @Override
     public boolean shouldDisableDependents() {
-        boolean shouldDisable = mDisableDependentsState ? mChecked : !mChecked;
+        boolean shouldDisable = mDisableDependentsState == mChecked;
         return shouldDisable || super.shouldDisableDependents();
     }
 

material_preferences_library/src/main/res/layout/mpl__preference_widget_checkbox.xml

@@ -17,7 +17,7 @@
      inside android.R.layout.preference. -->
 <androidx.appcompat.widget.AppCompatCheckBox xmlns:android="http://schemas.android.com/apk/res/android"
                                              xmlns:tools="http://schemas.android.com/tools"
-                                             android:id="@+android:id/checkbox"
+                                             android:id="@android:id/checkbox"
                                              android:layout_width="wrap_content"
                                              android:layout_height="wrap_content"
                                              android:background="@null"