Android example source code file (AnimatingLine.java)

This example Android source code file (AnimatingLine.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

animatingline, direction, shape2d

The AnimatingLine.java Android example source code

/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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.divideandconquer;

/**
 * Keeps the state for the line that extends in two directions until it hits its boundaries.  This is triggered
 * by the user gesture in a horizontal or vertical direction.
 */
public class AnimatingLine extends Shape2d {

    private Direction mDirection;

    // for vertical lines, the y offset
    // for horizontal, the x offset
    float mPerpAxisOffset;

    float mStart;
    float mEnd;

    float mMin;
    float mMax;

    private long mLastUpdate = 0;
    private float mPixelsPerSecond = 101.0f;

    /**
     * @param direction The direction of the line
     * @param now What 'now' is
     * @param axisStart Where on the perpindicular axis the line is extending from
     * @param start The point the line is extending from on the parallel axis
     * @param min The lower bound for the line (i.e the left most point)
     * @param max The upper bound for the line (i.e the right most point)
     */
    public AnimatingLine(
            Direction direction,
            long now,
            float axisStart,
            float start,
            float min, float max) {
        mDirection = direction;
        mLastUpdate = now;
        mPerpAxisOffset = axisStart;
        mStart = mEnd = start;
        mMin = min;
        mMax = max;
    }

    public Direction getDirection() {
        return mDirection;
    }

    public float getPerpAxisOffset() {
        return mPerpAxisOffset;
    }

    public float getStart() {
        return mStart;
    }

    public float getEnd() {
        return mEnd;
    }

    public float getMin() {
        return mMin;
    }

    public float getMax() {
        return mMax;
    }

    public float getLeft() {
        return mDirection == Direction.Horizontal ? mStart : mPerpAxisOffset;
    }

    public float getRight() {
        return mDirection == Direction.Horizontal ? mEnd : mPerpAxisOffset;
    }

    public float getTop() {
        return mDirection == Direction.Vertical ? mStart : mPerpAxisOffset;
    }

    public float getBottom() {
        return mDirection == Direction.Vertical ? mEnd : mPerpAxisOffset;
    }

    public float getPercentageDone() {
        return (mEnd - mStart) / (mMax - mMin);
    }

    /**
     * Extend the line according to the animation.
     * @return whether the line has reached its end.
     */
    public boolean update(long time) {
        if (time == mLastUpdate) return false;
        float delta = (time - mLastUpdate) * mPixelsPerSecond;
        delta = delta / 1000;
        mLastUpdate = time;
        mStart -= delta;
        mEnd += delta;

        if (mStart < mMin) mStart = mMin;
        if (mEnd > mMax) mEnd = mMax;

        return mStart == mMin && mEnd == mMax;
    }

    public void setNow(long now) {
        mLastUpdate = now;
    }
}