src/com/android/datetimepicker/time/CircleView.java

/*
 * Copyright (C) 2013 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.datetimepicker.time;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.Log;
import android.view.View;

import com.android.datetimepicker.R;

/**
 * Draws a simple white circle on which the numbers will be drawn.
 */
class CircleView extends View {
    private static final String TAG = "CircleView";

    private final Paint mPaint = new Paint();
    private boolean mIs24HourMode;
    private int mCircleColor;
    private int mDotColor;
    private float mCircleRadiusMultiplier;
    private float mAmPmCircleRadiusMultiplier;
    private boolean mIsInitialized;

    private boolean mDrawValuesReady;
    private int mXCenter;
    private int mYCenter;
    private int mCircleRadius;

    public CircleView(Context context) {
        super(context);

        Resources res = context.getResources();
        mCircleColor = res.getColor(android.R.color.white);
        mDotColor = res.getColor(R.color.numbers_text_color);
        mPaint.setAntiAlias(true);

        mIsInitialized = false;
    }

    public void initialize(Context context, boolean is24HourMode) {
        if (mIsInitialized) {
            Log.e(TAG, "CircleView may only be initialized once.");
            return;
        }

        Resources res = context.getResources();
        mIs24HourMode = is24HourMode;
        if (is24HourMode) {
            mCircleRadiusMultiplier = Float.parseFloat(
                    res.getString(R.string.circle_radius_multiplier_24HourMode));
        } else {
            mCircleRadiusMultiplier = Float.parseFloat(
                    res.getString(R.string.circle_radius_multiplier));
            mAmPmCircleRadiusMultiplier =
                    Float.parseFloat(res.getString(R.string.ampm_circle_radius_multiplier));
        }

        mIsInitialized = true;
    }

    /* package */ void setTheme(Context context, boolean dark) {
        Resources res = context.getResources();
        if (dark) {
            mCircleColor = res.getColor(R.color.dark_gray);
            mDotColor = res.getColor(R.color.light_gray);
        } else {
            mCircleColor = res.getColor(android.R.color.white);
            mDotColor = res.getColor(R.color.numbers_text_color);
        }
    }


    @Override
    public void onDraw(Canvas canvas) {
        int viewWidth = getWidth();
        if (viewWidth == 0 || !mIsInitialized) {
            return;
        }

        if (!mDrawValuesReady) {
            mXCenter = getWidth() / 2;
            mYCenter = getHeight() / 2;
            mCircleRadius = (int) (Math.min(mXCenter, mYCenter) * mCircleRadiusMultiplier);

            if (!mIs24HourMode) {
                // We'll need to draw the AM/PM circles, so the main circle will need to have
                // a slightly higher center. To keep the entire view centered vertically, we'll
                // have to push it up by half the radius of the AM/PM circles.
                int amPmCircleRadius = (int) (mCircleRadius * mAmPmCircleRadiusMultiplier);
                mYCenter -= amPmCircleRadius / 2;
            }

            mDrawValuesReady = true;
        }

        // Draw the white circle.
        mPaint.setColor(mCircleColor);
        canvas.drawCircle(mXCenter, mYCenter, mCircleRadius, mPaint);

        // Draw a small black circle in the center.
        mPaint.setColor(mDotColor);
        canvas.drawCircle(mXCenter, mYCenter, 2, mPaint);
    }
}