Fix NPE when calculating baseline for text fields. Fixes #184

core/src/main/java/com/github/weisj/darklaf/ui/text/bridge/DarkTextFieldUIBridge.java

@@ -32,6 +32,7 @@ import javax.swing.text.*;
 
 import com.github.weisj.darklaf.ui.text.DarkTextFieldUI;
 import com.github.weisj.darklaf.ui.text.DarkTextUI;
+import com.github.weisj.darklaf.ui.text.dummy.DummyTextFieldUI;
 
 /**
  * This class is an exact copy of the implementation of {@link BasicTextFieldUI}. In this way it is possible to contain
@@ -42,7 +43,7 @@ import com.github.weisj.darklaf.ui.text.DarkTextUI;
  */
 public abstract class DarkTextFieldUIBridge extends DarkTextUI {
 
-    private static final BasicTextFieldUI basicTextFieldUI = new BasicTextFieldUI();
+    private static final DummyTextFieldUI basicTextFieldUI = new DummyTextFieldUI();
 
     protected String getPropertyPrefix() {
         return "TextField";
@@ -55,6 +56,7 @@ public abstract class DarkTextFieldUIBridge extends DarkTextUI {
 
     @Override
     public int getBaseline(final JComponent c, final int width, final int height) {
+        basicTextFieldUI.setRootView(getRootView((JTextComponent) c));
         return basicTextFieldUI.getBaseline(c, width, height);
     }
 

core/src/main/java/com/github/weisj/darklaf/ui/text/dummy/DummyTextFieldUI.java

@@ -0,0 +1,43 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.ui.text.dummy;
+
+import javax.swing.plaf.basic.BasicTextFieldUI;
+import javax.swing.text.JTextComponent;
+import javax.swing.text.View;
+
+public class DummyTextFieldUI extends BasicTextFieldUI {
+
+    private View rootView;
+
+    @Override
+    public View getRootView(final JTextComponent tc) {
+        return rootView != null ? rootView : super.getRootView(tc);
+    }
+
+    public void setRootView(final View rootView) {
+        this.rootView = rootView;
+    }
+}