src/main/java/com/google/android/libraries/feed/sharedstream/ui/MaterialSpinnerView.java

// Copyright 2018 The Feed Authors.
//
// 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.libraries.feed.sharedstream.ui;

import android.content.Context;
import android.content.res.Resources.Theme;
import android.support.v7.widget.AppCompatImageView;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;
import android.support.v4.widget.CircularProgressDrawable;

/** View compatible with KitKat that shows a Material themed spinner. */
public class MaterialSpinnerView extends AppCompatImageView {

  private final CircularProgressDrawable spinner;

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

  public MaterialSpinnerView(Context context, /*@Nullable*/ AttributeSet attrs) {
    this(context, attrs, 0);
  }

  // In android everything is initialized properly after the constructor call, so it is fine to do
  // this work after.
  @SuppressWarnings({"nullness:argument.type.incompatible", "nullness:method.invocation.invalid"})
  public MaterialSpinnerView(Context context, /*@Nullable*/ AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    spinner = new CircularProgressDrawable(context);
    spinner.setStyle(CircularProgressDrawable.DEFAULT);
    setImageDrawable(spinner);
    TypedValue typedValue = new TypedValue();
    Theme theme = context.getTheme();
    theme.resolveAttribute(R.attr.feedSpinnerColor, typedValue, true);
    spinner.setColorSchemeColors(typedValue.data);

    if (getVisibility() == View.VISIBLE) {
      spinner.start();
    }
  }

  @Override
  public void setVisibility(int visibility) {
    super.setVisibility(visibility);

    if (spinner.isRunning() && getVisibility() != View.VISIBLE) {
      spinner.stop();
    } else if (!spinner.isRunning() && getVisibility() == View.VISIBLE) {
      spinner.start();
    }
  }
}