Android View that shows a dummy checkered pattern

CheckerView.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.example.android.pictureinpicture;

import android.animation.TimeAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class CheckerView extends View {

    private TimeAnimator mAnimator;
    private long mTotalTime;

    private Paint mPaint;
    private int mColorLight;
    private int mColorDark;
    private int mColorFloating;
    private int mCheckerSize;

    private final TimeAnimator.TimeListener mTimeListener = new TimeAnimator.TimeListener() {
        @Override
        public void onTimeUpdate(TimeAnimator animator, long totalTime, long deltaTime) {
            mTotalTime = totalTime;
            invalidate();
        }
    };

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

    public CheckerView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CheckerView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mPaint = new Paint();
        mColorLight = context.getColor(R.color.checker_light);
        mColorDark = context.getColor(R.color.checker_dark);
        mColorFloating = context.getColor(R.color.checker_floating);
        mCheckerSize = context.getResources().getDimensionPixelSize(R.dimen.checker_size);
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        start();
    }

    @Override
    protected void onDetachedFromWindow() {
        stop();
        super.onDetachedFromWindow();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        final float offset = mTotalTime * 0.1f;
        final int width = canvas.getWidth();
        final int height = canvas.getHeight();

        // Draw checkered pattern
        final float startLeft = (offset % mCheckerSize) - mCheckerSize;
        final float startTop = (-offset % mCheckerSize) - mCheckerSize;
        boolean startLight = true;
        for (float left = startLeft; left < width; left += mCheckerSize) {
            boolean light = startLight;
            for (float top = startTop; top < height; top += mCheckerSize) {
                mPaint.setColor(light ? mColorLight : mColorDark);
                canvas.drawRect(left, top, left + mCheckerSize, top + mCheckerSize, mPaint);
                light = !light;
            }
            startLight = !startLight;
        }

        // Draw a floating box
        final float absLeft = offset * 1.5f;
        final float horizontal = width - mCheckerSize;
        float left = absLeft % horizontal;
        if ((int) ((absLeft / horizontal) % 2) == 1) {
            left = horizontal - left;
        }
        final float absTop = offset * 1.3f;
        final float vertical = height - mCheckerSize;
        float top = absTop % vertical;
        if ((int) ((absTop / vertical) % 2) == 1) {
            top = vertical - top;
        }
        mPaint.setColor(mColorFloating);
        canvas.drawRect(left, top, left + mCheckerSize, top + mCheckerSize, mPaint);
    }

    public void start() {
        if (mAnimator == null) {
            mAnimator = new TimeAnimator();
            mAnimator.setTimeListener(mTimeListener);
            mAnimator.start();
        }
    }

    public void stop() {
        if (mAnimator != null) {
            mAnimator.end();
            mAnimator = null;
        }
    }

}

colors.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
 Copyright 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.
-->
<resources>
    <color name="checker_light">#9E9E9E</color>
    <color name="checker_dark">#616161</color>
    <color name="checker_floating">#FFEB3B</color>
</resources>

dimens.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
 Copyright 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.
-->
<resources>
    <dimen name="checker_size">64dp</dimen>
</resources>

DummyVideoView.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.example.android.pictureinpicture;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.FrameLayout;

public class DummyVideoView extends FrameLayout {

    private static final float ASPECT_RATIO = 9.f / 16.f;

    private CheckerView mCheckerView;

    public DummyVideoView(Context context) {
        super(context, null);
    }

    public DummyVideoView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public DummyVideoView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        inflate(context, R.layout.view_dummy_video, this);
        mCheckerView = (CheckerView) findViewById(R.id.checker);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        final int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        final int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        if (widthMode == MeasureSpec.EXACTLY && heightMode != MeasureSpec.EXACTLY) {
            super.onMeasure(widthMeasureSpec,
                    MeasureSpec.makeMeasureSpec((int) (widthSize * ASPECT_RATIO),
                            MeasureSpec.EXACTLY));
        } else if (widthMode != MeasureSpec.EXACTLY && heightMode == MeasureSpec.EXACTLY) {
            super.onMeasure(MeasureSpec.makeMeasureSpec((int) (heightSize / ASPECT_RATIO),
                    MeasureSpec.EXACTLY), heightMeasureSpec);
        } else if (widthMode == MeasureSpec.AT_MOST && heightMode == MeasureSpec.AT_MOST) {
            final int height = (int) (widthSize * ASPECT_RATIO);
            if (height < heightSize) {
                super.onMeasure(widthMeasureSpec,
                        MeasureSpec.makeMeasureSpec((int) (widthSize * ASPECT_RATIO),
                                MeasureSpec.EXACTLY));
            } else {
                super.onMeasure(MeasureSpec.makeMeasureSpec((int) (heightSize / ASPECT_RATIO),
                        MeasureSpec.EXACTLY), heightMeasureSpec);
            }
        } else {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        }
    }

    public void start() {
        mCheckerView.start();
    }

    public void stop() {
        mCheckerView.stop();
    }

}

view_dummy_video.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
 Copyright 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.
-->
<merge xmlns:android="http://schemas.android.com/apk/res/android">

    <com.example.android.pictureinpicture.CheckerView
        android:id="@+id/checker"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:orientation="horizontal"
        android:padding="8dp">

        <Space
            android:layout_width="0dp"
            android:layout_height="1dp"
            android:layout_weight="1"/>

        <ImageButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="?android:attr/selectableItemBackgroundBorderless"
            android:src="@drawable/ic_picture_in_picture_alt"/>

    </LinearLayout>

</merge>