com/android/setupwizardlib/view/CheckableLinearLayout.java

/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.setupwizardlib.view;

import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build.VERSION_CODES;
import androidx.annotation.Nullable;
import android.util.AttributeSet;
import android.widget.Checkable;
import android.widget.LinearLayout;

/**
 * A LinearLayout which is checkable. This will set the checked state when {@link
 * #onCreateDrawableState(int)} is called, and can be used with {@code android:duplicateParentState}
 * to propagate the drawable state to child views.
 */
public class CheckableLinearLayout extends LinearLayout implements Checkable {

  private boolean checked = false;

  public CheckableLinearLayout(Context context) {
    super(context);
  }

  public CheckableLinearLayout(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
  }

  @TargetApi(VERSION_CODES.HONEYCOMB)
  public CheckableLinearLayout(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
  }

  @TargetApi(VERSION_CODES.LOLLIPOP)
  public CheckableLinearLayout(
      Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
  }

  {
    setFocusable(true);
  }

  @Override
  protected int[] onCreateDrawableState(int extraSpace) {
    if (this.checked) {
      final int[] superStates = super.onCreateDrawableState(extraSpace + 1);
      final int[] checked = new int[] {android.R.attr.state_checked};
      return mergeDrawableStates(superStates, checked);
    } else {
      return super.onCreateDrawableState(extraSpace);
    }
  }

  @Override
  public void setChecked(boolean checked) {
    this.checked = checked;
    refreshDrawableState();
  }

  @Override
  public boolean isChecked() {
    return checked;
  }

  @Override
  public void toggle() {
    setChecked(!isChecked());
  }
}