[Button] Fixed a bug that checked state in XML was not respected.

PiperOrigin-RevId: 755123809

Author: pekingme

lib/java/com/google/android/material/button/MaterialButton.java

@@ -309,6 +309,9 @@ public MaterialButton(@NonNull Context context, @Nullable AttributeSet attrs, in
     materialButtonHelper = new MaterialButtonHelper(this, shapeAppearanceModel);
     materialButtonHelper.loadFromAttributes(attributes);
 
+    // Sets the checked state after the MaterialButtonHelper is initialized.
+    setCheckedInternal(attributes.getBoolean(R.styleable.MaterialButton_android_checked, false));
+
     if (stateListShapeAppearanceModel != null) {
       materialButtonHelper.setCornerSpringForce(createSpringForce());
       materialButtonHelper.setStateListShapeAppearanceModel(stateListShapeAppearanceModel);
@@ -1296,6 +1299,10 @@ public void clearOnCheckedChangeListeners() {
 
   @Override
   public void setChecked(boolean checked) {
+    setCheckedInternal(checked);
+  }
+
+  private void setCheckedInternal(boolean checked) {
     if (isCheckable() && this.checked != checked) {
       this.checked = checked;
 

lib/java/com/google/android/material/button/res/values/attrs.xml

@@ -50,6 +50,7 @@
 
   <declare-styleable name="MaterialButton">
     <!-- Whether the button can be checked. -->
+    <attr name="android:checked" />
     <attr name="android:checkable" />
     <attr name="android:insetLeft" />
     <attr name="android:insetRight" />