JakeWharton/butterknife · error · IllegalStateException

@BindArray field type must be one of: String[], int[], CharS

Error message

@BindArray field type must be one of: String[], int[], CharSequence[], android.content.res.TypedArray. (

What it means

This branch of parseBindArray throws when the field is an array type but its component type is none of the supported ones (String, int, CharSequence). @BindArray can only populate String[], int[], CharSequence[], or TypedArray; e.g. `long[]` or `Integer[]` hits this IllegalStateException at bind time.

Source

Thrown at butterknife-reflect/src/main/java/butterknife/ButterKnife.java:385

    validateMember(field);

    int id = bindArray.value();
    Resources resources = source.getContext().getResources();

    Object value;
    Class<?> fieldType = field.getType();
    if (fieldType == TypedArray.class) {
      value = resources.obtainTypedArray(id);
    } else if (fieldType.isArray()) {
      Class<?> componentType = fieldType.getComponentType();
      if (componentType == String.class) {
        value = resources.getStringArray(id);
      } else if (componentType == int.class) {
        value = resources.getIntArray(id);
      } else if (componentType == CharSequence.class) {
        value = resources.getTextArray(id);
      } else {
        throw new IllegalStateException("@BindArray field type must be one of: "
            + "String[], int[], CharSequence[], android.content.res.TypedArray. ("
            + field.getDeclaringClass().getName()
            + '.'
            + field.getName()
            + ')');
      }
    } else {
      throw new IllegalStateException("@BindArray field type must be one of: "
          + "String[], int[], CharSequence[], android.content.res.TypedArray. ("
          + field.getDeclaringClass().getName()
          + '.'
          + field.getName()
          + ')');
    }
    trySet(field, target, value);

    return Unbinder.EMPTY;
  }

View on GitHub (pinned to fcdebedf32)

Solutions

1. Use one of the supported types: String[], int[], CharSequence[], or TypedArray
2. For a boxed Integer[] need, switch the field to int[] and box values yourself after bind

Example fix

// before
@BindArray(R.array.page_offsets)
Integer[] offsets;

// after
@BindArray(R.array.page_offsets)
int[] offsets;

Class<?> c = field.getType().getComponentType();
if (c != String.class && c != int.class && c != CharSequence.class) {
  throw new IllegalStateException("Unsupported @BindArray component: " + c);
}

static boolean isSupportedArrayComponent(Class<?> c) {
  return c == String.class || c == int.class || c == CharSequence.class;
}

When it happens

Trigger: `@BindArray(R.array.ids) long[] ids;`, `@BindArray(...) Integer[] values;` (boxed Integer is not supported), or any other unsupported array component.

Common situations: Resource arrays defined as integers but the field declared boxed; using long arrays for large ID lists; code generation that picks a wrong component type.

Related errors

• @BindView fields must extend from View or be an interface. (
• @BindViews must be a List or array. (
• @BindViews List or array type must extend from View or be an
• @BindAnim field type must be 'Animation'. (
• @BindBitmap field type must be 'Bitmap'. (

AI-assisted analysis of JakeWharton/butterknife@fcdebedf32 (2026-08-14). Data as JSON: /api/errors/854836f9d8761a49. Report an issue: GitHub.