main/src/com/google/android/setupdesign/template/ProgressBarMixin.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.google.android.setupdesign.template;

import android.content.res.ColorStateList;
import android.os.Build;
import android.os.Build.VERSION_CODES;
import androidx.annotation.Nullable;
import android.view.View;
import android.view.ViewStub;
import android.widget.ProgressBar;
import com.google.android.setupcompat.internal.TemplateLayout;
import com.google.android.setupcompat.template.Mixin;
import com.google.android.setupdesign.R;

/** A {@link Mixin} for showing a progress bar. */
public class ProgressBarMixin implements Mixin {

  private final TemplateLayout templateLayout;

  @Nullable private ColorStateList color;

  /** @param layout The layout this mixin belongs to. */
  public ProgressBarMixin(TemplateLayout layout) {
    templateLayout = layout;
  }

  /** @return True if the progress bar is currently shown. */
  public boolean isShown() {
    final View progressBar = templateLayout.findManagedViewById(R.id.sud_layout_progress);
    return progressBar != null && progressBar.getVisibility() == View.VISIBLE;
  }

  /**
   * Sets whether the progress bar is shown. If the progress bar has not been inflated from the
   * stub, this method will inflate the progress bar.
   *
   * @param shown True to show the progress bar, false to hide it.
   */
  public void setShown(boolean shown) {
    if (shown) {
      View progressBar = getProgressBar();
      if (progressBar != null) {
        progressBar.setVisibility(View.VISIBLE);
      }
    } else {
      View progressBar = peekProgressBar();
      if (progressBar != null) {
        progressBar.setVisibility(View.GONE);
      }
    }
  }

  /**
   * Gets the progress bar in the layout. If the progress bar has not been used before, it will be
   * installed (i.e. inflated from its view stub).
   *
   * @return The progress bar of this layout. May be null only if the template used doesn't have a
   *     progress bar built-in.
   */
  private ProgressBar getProgressBar() {
    final View progressBar = peekProgressBar();
    if (progressBar == null) {
      final ViewStub progressBarStub =
          (ViewStub) templateLayout.findManagedViewById(R.id.sud_layout_progress_stub);
      if (progressBarStub != null) {
        progressBarStub.inflate();
      }
      setColor(color);
    }
    return peekProgressBar();
  }

  /**
   * Gets the progress bar in the layout only if it has been installed. {@link #setShown(boolean)}
   * should be called before this to ensure the progress bar is set up correctly.
   *
   * @return The progress bar of this layout, or null if the progress bar is not installed. The null
   *     case can happen either if {@link #setShown(boolean)} with true was not called before this,
   *     or if the template does not contain a progress bar.
   */
  public ProgressBar peekProgressBar() {
    return (ProgressBar) templateLayout.findManagedViewById(R.id.sud_layout_progress);
  }

  /** Sets the color of the indeterminate progress bar. This method is a no-op on SDK < 21. */
  public void setColor(@Nullable ColorStateList color) {
    this.color = color;
    if (Build.VERSION.SDK_INT >= VERSION_CODES.LOLLIPOP) {
      final ProgressBar bar = peekProgressBar();
      if (bar != null) {
        bar.setIndeterminateTintList(color);
        if (Build.VERSION.SDK_INT >= VERSION_CODES.M || color != null) {
          // There is a bug in Lollipop where setting the progress tint color to null
          // will crash with "java.lang.NullPointerException: Attempt to invoke virtual
          // method 'int android.graphics.Paint.getAlpha()' on a null object reference"
          // at android.graphics.drawable.NinePatchDrawable.draw(:250)
          // The bug doesn't affect ProgressBar on M because it uses ShapeDrawable instead
          // of NinePatchDrawable. (commit 6a8253fdc9f4574c28b4beeeed90580ffc93734a)
          bar.setProgressBackgroundTintList(color);
        }
      }
    }
  }

  /**
   * @return The color previously set in {@link #setColor(ColorStateList)}, or null if the color is
   *     not set. In case of null, the color of the progress bar will be inherited from the theme.
   */
  @Nullable
  public ColorStateList getColor() {
    return color;
  }
}