java/src/com/android/inputmethod/keyboard/emoji/EmojiCategoryPageIndicatorView.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.inputmethod.keyboard.emoji;

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

public final class EmojiCategoryPageIndicatorView extends View {
    private static final float BOTTOM_MARGIN_RATIO = 1.0f;
    private final Paint mPaint = new Paint();
    private int mCategoryPageSize = 0;
    private int mCurrentCategoryPageId = 0;
    private float mOffset = 0.0f;

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

    public EmojiCategoryPageIndicatorView(final Context context, final AttributeSet attrs,
            final int defStyle) {
        super(context, attrs, defStyle);
    }

    public void setColors(final int foregroundColor, final int backgroundColor) {
        mPaint.setColor(foregroundColor);
        setBackgroundColor(backgroundColor);
    }

    public void setCategoryPageId(final int size, final int id, final float offset) {
        mCategoryPageSize = size;
        mCurrentCategoryPageId = id;
        mOffset = offset;
        invalidate();
    }

    @Override
    protected void onDraw(final Canvas canvas) {
        if (mCategoryPageSize <= 1) {
            // If the category is not set yet or contains only one category,
            // just clear and return.
            canvas.drawColor(0);
            return;
        }
        final float height = getHeight();
        final float width = getWidth();
        final float unitWidth = width / mCategoryPageSize;
        final float left = unitWidth * mCurrentCategoryPageId + mOffset * unitWidth;
        final float top = 0.0f;
        final float right = left + unitWidth;
        final float bottom = height * BOTTOM_MARGIN_RATIO;
        canvas.drawRect(left, top, right, bottom, mPaint);
    }
}