material-components_material-components-android/lib/java/com/google/android/material/checkbox/MaterialCheckBox.java

/*
 * Copyright (C) 2018 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.google.android.material.checkbox;

import com.google.android.material.R;

import android.content.Context;
import android.content.res.ColorStateList;
import android.support.annotation.Nullable;
import com.google.android.material.color.MaterialColors;
import android.support.v4.widget.CompoundButtonCompat;
import android.support.v7.widget.AppCompatCheckBox;
import android.util.AttributeSet;

/**
 * A class that creates a Material Themed CheckBox.
 *
 * <p>This class uses attributes from the Material Theme to style a CheckBox. Excepting color
 * changes, it behaves identically to {@link AppCompatCheckBox}. Your theme's {@code
 * ?attr/colorSecondary}, {@code ?attr/colorSurface}, and {@code ?attr/colorOnSurface} must be set.
 */
public class MaterialCheckBox extends AppCompatCheckBox {

  private final int[][] enabledCheckedStates =
      new int[][] {
        new int[] {android.R.attr.state_enabled, android.R.attr.state_checked}, // [0]
        new int[] {android.R.attr.state_enabled, -android.R.attr.state_checked}, // [1]
        new int[] {-android.R.attr.state_enabled, android.R.attr.state_checked}, // [2]
        new int[] {-android.R.attr.state_enabled, -android.R.attr.state_checked} // [3]
      };

  public MaterialCheckBox(Context context) {
    this(context, null);
  }

  public MaterialCheckBox(Context context, @Nullable AttributeSet attrs) {
    this(context, attrs, R.attr.checkboxStyle);
  }

  public MaterialCheckBox(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    if (CompoundButtonCompat.getButtonTintList(this) == null) {
      setColorThemedButtonTint();
    }
  }

  private void setColorThemedButtonTint() {
    int[] checkBoxColorsList = new int[enabledCheckedStates.length];
    int colorSecondary = MaterialColors.getColor(this, R.attr.colorSecondary);
    int colorSurface = MaterialColors.getColor(this, R.attr.colorSurface);
    int colorOnSurface = MaterialColors.getColor(this, R.attr.colorOnSurface);

    checkBoxColorsList[0] =
        MaterialColors.layer(colorSurface, colorSecondary, MaterialColors.ALPHA_FULL);
    checkBoxColorsList[1] =
        MaterialColors.layer(colorSurface, colorOnSurface, MaterialColors.ALPHA_MEDIUM);
    checkBoxColorsList[2] =
        MaterialColors.layer(colorSurface, colorOnSurface, MaterialColors.ALPHA_DISABLED);
    checkBoxColorsList[3] =
        MaterialColors.layer(colorSurface, colorOnSurface, MaterialColors.ALPHA_DISABLED);

    CompoundButtonCompat.setButtonTintList(
        this, new ColorStateList(enabledCheckedStates, checkBoxColorsList));
  }
}