本篇内容主要讲解“Android怎么实现加载视差动画效果”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“Android怎么实现加载视差动画效果”吧!
继 Android实现旋转动画的两种方式 我们了解了 Android实现旋转的两种基本方法之后，我们来写一个综合案例
实现思路
从效果中我们可以看到 可以将其分为三个动画：
1、旋转动画（Android实现旋转动画的两种方式）
2、聚合动画
3、扩展动画
代码展示
package com.wust.mydialog;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
import android.view.WindowManager;
import android.view.animation.AnticipateInterpolator;
import android.view.animation.LinearInterpolator;
import androidx.annotation.Nullable;
/**
* ClassName: com.wust.mydialog.MyRotateView <br/>
* Description: <br/>
* date: 2021/8/7 12:13<br/>
*
* @author yiqi<br />
* @QQ 1820762465
* @微信 yiqiideallife
* @技术交流QQ群 928023749
*/
public class MyRotateView extends View {
//设置旋转间隔时间
private int SPLASH_CIRCLE_ROTATE_TIME = 1000;
//设置中心圆半径
private float CENTER_CIRCLE_RADIUS;
private float SMALL_CIRCLE_RADIUS;
private float mCurrentSingle = 0f;
private int[] mColorArray;
private Paint mCirclePaint;
private ValueAnimator va;
private Matrix mSpaceMatrix;
private LoadingState mLoadingState;
//当前中心圆半径
private float mCurCenterRadius;
private float mDiagonal;
private float mLineWidth;
public MyRotateView(Context context) {
super(context);
}
public MyRotateView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}
public MyRotateView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
//初始化参数
initParams(width, height);
setMeasuredDimension(width, height);
}
private void initParams(int w, int h) {
//设置中心圆半径
CENTER_CIRCLE_RADIUS = 1 / 4.0f * w;
//设置小圆的半径
SMALL_CIRCLE_RADIUS = 1 / 25.0f * w;
//获取小球颜色
mColorArray = getResources().getIntArray(R.array.splash_circle_colors);
//初始化画笔
mCirclePaint = new Paint();
mCirclePaint.setDither(true);
mCirclePaint.setAntiAlias(true);
//初始化旋转矩阵
mSpaceMatrix = new Matrix();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mLoadingState == null) {
mLoadingState = new RotateState();
}
mLoadingState.onDraw(canvas);
}
//定义 状态 抽象类
private abstract class LoadingState {
public abstract void onDraw(Canvas canvas);
}
//旋转动画
private class RotateState extends LoadingState {
public RotateState() {
//计算每个小球的间隔
double spaceAngle = 360.0d / mColorArray.length;
//初始化旋转矩阵
mSpaceMatrix.reset();
mSpaceMatrix.postRotate((float) spaceAngle, getWidth() / 2, getHeight() / 2);
va = ObjectAnimator.ofFloat(0f, 360.0f);
va.setDuration(SPLASH_CIRCLE_ROTATE_TIME);
va.setRepeatCount(ValueAnimator.INFINITE);
va.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
mCurrentSingle = (float) animation.getAnimatedValue();
invalidate();
}
});
va.setInterpolator(new LinearInterpolator());
va.start();
}
@Override
public void onDraw(Canvas canvas) {
//绘制背景
canvas.drawColor(Color.WHITE);
//利用旋转画布法
canvas.save();
canvas.rotate(mCurrentSingle, getWidth() / 2, getHeight() / 2);
for (int i = 0; i < mColorArray.length; i++) {
canvas.concat(mSpaceMatrix);
//为 每个球 画笔 设置颜色
mCirclePaint.setColor(mColorArray[i]);
//利用旋转画布法
float cx = getWidth() / 2 + CENTER_CIRCLE_RADIUS;
float cy = getHeight() / 2;
canvas.drawCircle(cx, cy, SMALL_CIRCLE_RADIUS, mCirclePaint);
}
canvas.restore();
}
}
//聚合动画
private class ScaleState extends LoadingState {
public ScaleState() {
va = ObjectAnimator.ofFloat(CENTER_CIRCLE_RADIUS,0);
va.setDuration(SPLASH_CIRCLE_ROTATE_TIME);
va.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
mCurCenterRadius = (float) animation.getAnimatedValue();
invalidate();
}
});
va.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
mLoadingState = new ExtentState();
}
});
va.setInterpolator(new AnticipateInterpolator());
va.start();
}
@Override
public void onDraw(Canvas canvas) {
//绘制背景
canvas.drawColor(Color.WHITE);
//绘制小圆
canvas.save();
//这句话也不能调，要不然不连贯
canvas.rotate(mCurrentSingle,getWidth()/2,getHeight()/2);
for (int i = 0; i < mColorArray.length; i++) {
mCirclePaint.setColor(mColorArray[i]);
canvas.concat(mSpaceMatrix);
canvas.drawCircle(mCurCenterRadius+getWidth()/2,getHeight()/2,SMALL_CIRCLE_RADIUS,mCirclePaint);
}
canvas.restore();
}
}
//扩展动画
public class ExtentState extends LoadingState{
public ExtentState() {
//初始化对角线
float cx = getWidth()/2.0f;
float cy = getHeight()/2.0f;
mDiagonal = (float) Math.sqrt(Math.pow(cx,2)+Math.pow(cy,2));
va = ObjectAnimator.ofFloat(mDiagonal,0);
va.setDuration(3000);
va.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
mLineWidth = (float) animation.getAnimatedValue();
invalidate();
}
});
va.setInterpolator(new LinearInterpolator());
va.start();
}
@Override
public void onDraw(Canvas canvas) {
mCirclePaint.setColor(Color.WHITE);
mCirclePaint.setStrokeWidth(mLineWidth*2);//元的半径只会到达线宽的中间，所以要乘2
mCirclePaint.setStyle(Paint.Style.STROKE);
canvas.drawCircle(getWidth()/2,getHeight()/2,mDiagonal,mCirclePaint);
}
}
public void dismiss() {
if (mLoadingState instanceof RotateState){
//取消旋转值动画
va.cancel();
//创建缩放动画
mLoadingState = new ScaleState();
//刷新布局、可以写也可以不写
// invalidate();
}
}
}到此，相信大家对“Android怎么实现加载视差动画效果”有了更深的了解，不妨来实际操作一番吧！这里是亿速云网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
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