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

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脚本之家。