本文实例为大家分享了Android实现两圆点之间来回移动加载进度的具体代码，供大家参考，具体内容如下

一、前言

最近喜欢上自定义控件，喜欢实现一些简约有趣的控件，也好巩固下以前学得知识和不断的学习新知识，程序员嘛，活到老学到老。

这篇文章接着上一篇文章：Android_自定义控件之水平圆点加载进度条，类似的实现方式，都是些比较简单的view绘制。

二、实现

先看下实现的效果吧：

说下实现思路：圆点x轴会有个位移变化量，当位移达到圆点直径+圆点间距之和就回改变方向（改变方向就是通过变化量值不断增加和不断减少来实现），可能写的有点模糊，接下来看代码：

package com.kincai.testcustomview_dotalternatelyprogress; import android.content.Context;import android.content.res.TypedArray;import android.graphics.Canvas;import android.graphics.Paint;import android.support.annotation.Nullable;import android.support.v4.content.ContextCompat;import android.util.AttributeSet;import android.util.Log;import android.view.View; /** * Copyright (C) 2015 The KINCAI Open Source Project * . * Create By KINCAI * . * Time 2017-06-16 21:44 * . * Desc 两个源点来回移动 */ public class DotAlternatelyView extends View { private final String TAG = this.getClass().getSimpleName(); private Paint mPaint = new Paint(); /** * 可视为左边圆点颜色值 */ private int mLeftColor; /** * 可视为右边圆点颜色值 */ private int mRightColor; /** * 圆点半径 */ private int mDotRadius; /** * 圆点间距 */ private int mDotSpacing; /** * 圆点位移量 */ private float mMoveDistance; /** * 圆点移动率 */ private float mMoveRate; /** * 以刚开始左边圆点为准 向右移 */ private final int DOT_STATUS_RIGHT = 0X101; /** * 以刚开始左边圆点为准 圆点移动方向-向左移 */ private final int DOT_STATUS_LEFT = 0X102; /** * 以刚开始左边圆点为准，圆点移动方向 */ private int mDotChangeStatus = DOT_STATUS_RIGHT; /** * 圆点透明度变化最大(也就是透明度在255-mAlphaChangeTotal到255之间) */ private int mAlphaChangeTotal = 130; /** * 透明度变化率 */ private float mAlphaChangeRate; /** * 透明度改变量 */ private float mAlphaChange; public DotAlternatelyView(Context context) { this(context, null); } public DotAlternatelyView(Context context, @Nullable AttributeSet attrs) { this(context, attrs, 0); } public DotAlternatelyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.DotAlternatelyView, defStyleAttr, 0); initAttributes(typedArray); typedArray.recycle(); init(); } private void initAttributes(TypedArray Attributes) { mLeftColor = Attributes.getColor(R.styleable.DotAlternatelyView_dot_dark_color, ContextCompat.getColor(getContext(), R.color.colorPrimary)); mRightColor = Attributes.getColor(R.styleable.DotAlternatelyView_dot_light_color, ContextCompat.getColor(getContext(), R.color.colorAccent)); mDotRadius = Attributes.getDimensionPixelSize(R.styleable.DotAlternatelyView_dot_radius, DensityUtils.dp2px(getContext(), 3)); mDotSpacing = Attributes.getDimensionPixelSize(R.styleable.DotAlternatelyView_dot_spacing, DensityUtils.dp2px(getContext(), 6)); mMoveRate = Attributes.getFloat(R.styleable.DotAlternatelyView_dot_move_rate, 1.2f); } /** * 初始化 */ private void init() { //移动总距离/移动率 = alpha总变化/x //x = 移动率 * alpha总变化 / 移动总距离 mAlphaChangeRate = mMoveRate * mAlphaChangeTotal / (mDotRadius * 2 + mDotSpacing); mPaint.setColor(mLeftColor); mPaint.setAntiAlias(true); mPaint.setStyle(Paint.Style.FILL); Log.e(TAG, " aaaa " + mAlphaChangeRate); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { //测量宽高 int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int width; int height; if (widthMode == MeasureSpec.EXACTLY) { width = widthSize; Log.e(TAG, "onMeasure MeasureSpec.EXACTLY widthSize=" + widthSize); } else { //指定最小宽度所有圆点加上间距的宽度, 以最小半径加上间距算总和再加上最左边和最右边变大后的距离 width = (mDotRadius * 2) * 2 + mDotSpacing; Log.e(TAG, "onMeasure no MeasureSpec.EXACTLY widthSize=" + widthSize + " width=" + width); if (widthMode == MeasureSpec.AT_MOST) { width = Math.min(width, widthSize); Log.e(TAG, "onMeasure MeasureSpec.AT_MOST width=" + width); } } if (heightMode == MeasureSpec.EXACTLY) { height = heightSize; Log.e(TAG, "onMeasure MeasureSpec.EXACTLY heightSize=" + heightSize); } else { height = mDotRadius * 2; Log.e(TAG, "onMeasure no MeasureSpec.EXACTLY heightSize=" + heightSize + " height=" + height); if (heightMode == MeasureSpec.AT_MOST) { height = Math.min(height, heightSize); Log.e(TAG, "onMeasure MeasureSpec.AT_MOST height=" + height); } } setMeasuredDimension(width, height); } @Override protected void onDraw(Canvas canvas) { //左边圆点起点x轴 int startPointX = getWidth() / 2 - (2 * mDotRadius * 2 + mDotSpacing) / 2 + mDotRadius; //左边圆点起点y轴 int startPointY = getHeight() / 2; //向右移 位移要增加对应透明度变化量也需要增加 反之都需要减小 if (mDotChangeStatus == DOT_STATUS_RIGHT) { mMoveDistance += mMoveRate; mAlphaChange += mAlphaChangeRate; } else { mAlphaChange -= mAlphaChangeRate; mMoveDistance -= mMoveRate; } Log.e(TAG, "mAlphaChange " + mAlphaChange); //当移动到最右 那么需要改变方向 反过来 if (mMoveDistance >= mDotRadius * 2 + mDotSpacing && mDotChangeStatus == DOT_STATUS_RIGHT) { mDotChangeStatus = DOT_STATUS_LEFT; mMoveDistance = mDotRadius * 2 + mDotSpacing; mAlphaChange = mAlphaChangeTotal; } else if (mMoveDistance <= 0 && mDotChangeStatus == DOT_STATUS_LEFT) { //当移动到最座 那么需要改变方向 反过来 mDotChangeStatus = DOT_STATUS_RIGHT; mMoveDistance = 0f; mAlphaChange = 0f; } //因为两个圆点可能会给定不同的颜色来显示 所以提供两种颜色设置mLeftColor和mRightColor mPaint.setColor(mLeftColor); mPaint.setAlpha((int) (255 - mAlphaChange)); canvas.drawCircle(startPointX + mMoveDistance, startPointY, mDotRadius, mPaint); mPaint.setColor(mRightColor); mPaint.setAlpha((int) (255 - mAlphaChange)); canvas.drawCircle(startPointX + mDotRadius * 2 - mMoveDistance + mDotSpacing, startPointY, mDotRadius, mPaint); invalidate(); }}

要是不容易理解的话，下载源码运行再对着源码看会容易理解

源码下载github：Android移动加载进度

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。