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Android实现漂亮的波纹动画

本文章讲述如何使用二维画布canvas和camera、矩阵实现二、三维波纹动画效果（波纹大小变化、画笔透明度变化、画笔粗细变化）

一、UI界面

界面主要分为三部分
第一部分：输入框，根据输入x轴、Y轴、Z轴倾斜角度绘制波纹动画立体效果
第二部分：点击按钮PLAY：开始绘制动画；点击按钮STOP：停止绘制动画
第三部分：绘制波纹动画的自定义view

activity_main.xml实现如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:padding="16dp"android:gravity="center"android:orientation="vertical"><LinearLayoutandroid:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal"android:layout_marginBottom="8dp"><LinearLayoutandroid:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:orientation="vertical"android:gravity="center_horizontal"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="X轴倾斜" /><EditTextandroid:id="@+id/editText_X"android:layout_width="match_parent"android:layout_height="wrap_content"android:inputType="number"android:text="0"/></LinearLayout><LinearLayoutandroid:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:orientation="vertical"android:gravity="center_horizontal"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Y轴倾斜" /><EditTextandroid:id="@+id/editText_Y"android:layout_width="match_parent"android:layout_height="wrap_content"android:inputType="number"android:text="0"/></LinearLayout><LinearLayoutandroid:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:orientation="vertical"android:gravity="center_horizontal"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Z轴倾斜" /><EditTextandroid:id="@+id/editText_Z"android:layout_width="match_parent"android:layout_height="wrap_content"android:inputType="number"android:text="0"/></LinearLayout></LinearLayout><LinearLayoutandroid:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal"android:gravity="center"android:paddingTop="16dp"><Buttonandroid:id="@+id/playButton"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Play"android:layout_marginEnd="8dp"/><Buttonandroid:id="@+id/stopButton"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Stop"android:layout_marginEnd="8dp"/></LinearLayout><FrameLayoutandroid:layout_width="match_parent"android:layout_height="0dp"android:layout_weight="1"android:layout_gravity="center"><!-- WaveView --><com.example.waveanimationbysingleview.animation.WaveViewandroid:id="@+id/wave_view"android:layout_width="match_parent"android:layout_height="606dp"android:layout_gravity="center" /></FrameLayout></LinearLayout>

二、自定义view实现

新建一个WaveView类继承自View，声明类成员变量和实现构造函数初始化

public class WaveView extends View{private RippleAnimationInfo mRippleInfo;//动画属性类，包括最大、最小半径，光圈等private final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);private float centerX, centerY; //绘制画布中心点private float[] mRadiusArray;  // 存储当前绘制每圈光波的半径private float[] mAlphaArray;   //存储当前绘制每圈光波的透明度private float[] mStrokenArray; //存储当前绘制每圈光波的画笔宽度private final Camera mCamera = new Camera();//相机private final Matrix mMatrix = new Matrix();//矩阵private final RectF mRectF = new RectF();private Boolean mIsDrawing = false;//是否绘制标志位private Bitmap mLogoBitmap;//中心点表情😝logoprivate AnimatorSet mAnimatorSet = new AnimatorSet();//多动画组合类private List<Animator> mAnimatorList = new ArrayList<>();//存储动画列表public WaveView(Context context) {super(context);init();}public WaveView(Context context, AttributeSet attrs) {super(context, attrs);init();}public WaveView(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);init();}

构造函数初始化

添加动画

1. 圆圈等比变大动画
2. 透明度渐变动画
3. 画笔由细变粗动画

private void initAnimation() {int rippleDelay = mRippleInfo.durationTime/mRippleInfo.rippleCount;for (int i = 0; i < mRippleInfo.rippleCount; i++) {//动画1-半径变大final int index = i;ValueAnimator radiusAnimator = ValueAnimator.ofFloat(mRippleInfo.minRadius, mRippleInfo.maxRadius);radiusAnimator.setDuration(mRippleInfo.durationTime); // 动画持续时间radiusAnimator.setStartDelay(i * rippleDelay); // 延迟启动radiusAnimator.setRepeatCount(ValueAnimator.INFINITE);radiusAnimator.setRepeatMode(ValueAnimator.RESTART);radiusAnimator.addUpdateListener(animation -> {mRadiusArray[index] = (float) animation.getAnimatedValue();invalidate(); // 重绘视图});//动画2-画笔变粗ValueAnimator strokeAnimator = ObjectAnimator.ofFloat(mRippleInfo.minStrokenWidth, mRippleInfo.maxStrokenWidth);strokeAnimator.setDuration(mRippleInfo.durationTime); // 动画持续时间strokeAnimator.setStartDelay(i * rippleDelay); // 延迟启动strokeAnimator.setRepeatCount(ValueAnimator.INFINITE);strokeAnimator.setRepeatMode(ValueAnimator.RESTART);strokeAnimator.addUpdateListener(animation -> {mStrokenArray[index] = (float) animation.getAnimatedValue();invalidate(); // 重绘视图});//动画3-颜色淡出ValueAnimator alphaAnimator = ObjectAnimator.ofFloat( 0.1f, 0.8f, 0.8f,0.4f, 0);alphaAnimator.setDuration(mRippleInfo.durationTime); // 动画持续时间alphaAnimator.setStartDelay(i * rippleDelay); // 延迟启动alphaAnimator.setRepeatCount(ValueAnimator.INFINITE);alphaAnimator.setRepeatMode(ValueAnimator.RESTART);alphaAnimator.addUpdateListener(animation -> {mAlphaArray[index] = (float) animation.getAnimatedValue();invalidate(); // 重绘视图});mAnimatorList.add(radiusAnimator);mAnimatorList.add(strokeAnimator);mAnimatorList.add(alphaAnimator);}mAnimatorSet.playTogether(mAnimatorList);}

应用矩阵变换

重写ondraw

@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);if (!mIsDrawing){return;}canvas.save();// 计算中心点centerX = getWidth() / 2.0f;centerY = getHeight() / 2.0f;canvas.concat(mMatrix);// 将矩阵应用到画布上//绘制多圈波纹for (int i = 0; i < mRippleInfo.rippleCount; i++) {if (mRadiusArray[i] > 0) {paint.setStrokeWidth(mStrokenArray[i]);paint.setAlpha((int)(255 * mAlphaArray[i]));canvas.drawCircle(centerX, centerY,mRadiusArray[i],paint);}}// 中心点绘制 logocanvas.drawBitmap(mLogoBitmap, (getWidth()- mRippleInfo.minRadius)/2, (getHeight()- mRippleInfo.minRadius)/2, null);canvas.restore();}

二、二维波纹动画

三、三维波纹动画