lawnchair/quickstep/src/com/android/launcher3/taskbar/TaskbarView.java

/*
 * Copyright (C) 2021 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.launcher3.taskbar;

import android.content.Context;
import android.graphics.drawable.ColorDrawable;
import android.util.AttributeSet;
import android.widget.LinearLayout;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

/**
 * Hosts the Taskbar content such as Hotseat and Recent Apps. Drawn on top of other apps.
 */
public class TaskbarView extends LinearLayout {

    private final ColorDrawable mBackgroundDrawable;

    public TaskbarView(@NonNull Context context) {
        this(context, null);
    }

    public TaskbarView(@NonNull Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public TaskbarView(@NonNull Context context, @Nullable AttributeSet attrs,
            int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    public TaskbarView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr,
            int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        mBackgroundDrawable = (ColorDrawable) getBackground();
    }

    /**
     * Sets the alpha of the background color behind all the Taskbar contents.
     * @param alpha 0 is fully transparent, 1 is fully opaque.
     */
    public void setBackgroundAlpha(float alpha) {
        mBackgroundDrawable.setAlpha((int) (alpha * 255));
    }
}