由于开发的需要，需要开发类似直播点赞特效的需求，于是自定义View来实现这种效果

案例图：

1.自定义View

import android.animation.Animator;

import android.animation.AnimatorSet;

import android.animation.ObjectAnimator;

import android.animation.TypeEvaluator;

import android.animation.ValueAnimator;

import android.content.Context;

import android.graphics.PointF;

import android.graphics.drawable.Drawable;

import android.util.AttributeSet;

import android.view.View;

import android.view.animation.AccelerateDecelerateInterpolator;

import android.view.animation.AccelerateInterpolator;

import android.view.animation.DecelerateInterpolator;

import android.view.animation.Interpolator;

import android.view.animation.LinearInterpolator;

import android.widget.ImageView;

import android.widget.RelativeLayout;

import com.xinrui.ndkapp.R;

import java.util.Random;

/**

* Created by liuyong

* Data: 2017/8/8

* Github:https://github.com/MrAllRight

* 直播点赞view

*/

public class GivePraiseView extends RelativeLayout {

private RelativeLayout.LayoutParams layoutParams;//图片布局参数

private PointF mPointF0, mPointF1, mPointF2, mPointF3;//通过3阶贝塞尔曲线控制图片的移动轨迹

private int mScreenWidth, mScreenHeight;//屏幕宽高

private Drawable[] mImageDrawables;//加载点赞红心图片，红黄蓝

private int mDrawableWidth, mDrawableHeight;//图片的宽高

private Random mRandom = new Random();

private int count = 0;

private Interpolator[] interpolators = new Interpolator[4];

public GivePraiseView(Context context) {

super(context);

init();

}

public GivePraiseView(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

init();

}

public GivePraiseView(Context context, AttributeSet attrs) {

super(context, attrs);

init();

}

@Override

protected void onSizeChanged(int w, int h, int oldw, int oldh) {

super.onSizeChanged(w, h, oldw, oldh);

mScreenHeight = h;

mScreenWidth = w;

}

//初始化drawable，layoutParams

private void init() {

mImageDrawables = new Drawable[4];

mImageDrawables[0] = getResources().getDrawable(R.drawable.pl_blue);

mImageDrawables[1] = getResources().getDrawable(R.drawable.pl_red);

mImageDrawables[2] = getResources().getDrawable(R.drawable.pl_yellow);

mImageDrawables[3] = getResources().getDrawable(R.drawable.pl_red);

// 插值器

interpolators[0] = new AccelerateDecelerateInterpolator(); // 在动画开始与结束的地方速率改变比较慢，在中间的时候加速

interpolators[1] = new AccelerateInterpolator(); // 在动画开始的地方速率改变比较慢，然后开始加速

interpolators[2] = new DecelerateInterpolator(); // 在动画开始的地方快然后慢

interpolators[3] = new LinearInterpolator(); // 以常量速率改变

mDrawableWidth = mImageDrawables[0].getIntrinsicWidth();

mDrawableHeight = mImageDrawables[0].getIntrinsicHeight();

layoutParams = new LayoutParams(50, 50);

layoutParams.addRule(ALIGN_PARENT_BOTTOM, TRUE);

layoutParams.addRule(ALIGN_PARENT_RIGHT, TRUE);

layoutParams.setMargins(0, 0, 60, 60);//放置在屏幕的右下角

//这里为了演示我们现在布局初始化的时候，放置一个imageview，颜色随机，设置点击屏幕出现点赞效果

ImageView iv = new ImageView(getContext());

iv.setLayoutParams(layoutParams);

iv.setImageDrawable(mImageDrawables[0]);

addView(iv);

this.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

for(int i=0;i<10;i++) {

addGivePraiseImg(count);

count++;

if (count == 4) count = 0;

}

}

});

}

//点击图片是添加imageview到布局中，并添加动画

private void addGivePraiseImg(int count) {

final ImageView givepraiseImg = new ImageView(getContext());

givepraiseImg.setLayoutParams(layoutParams);

givepraiseImg.setImageDrawable(mImageDrawables[count]);

addView(givepraiseImg);

addAnimator(givepraiseImg);//添加动画效果，动画分两部分，第一部分是产生图片时缩放和透明度，第二部是移动图片再进行透明度变化

}

private void addAnimator(final ImageView imageView) {

//点击的时候，让图片经过放大，缩放效果，之后再开始沿着贝塞尔曲线的轨迹移动

ObjectAnimator alpha = ObjectAnimator.ofFloat(imageView, "alpha", 0.3f, 1f);

ObjectAnimator scaleX = ObjectAnimator.ofFloat(imageView, "scaleX", 0.2f, 1f);

ObjectAnimator scaleY = ObjectAnimator.ofFloat(imageView, "scaleY", 0.2f, 1f);

AnimatorSet set = new AnimatorSet();

set.setDuration(100);

set.playTogether(alpha, scaleX, scaleY);

set.setTarget(imageView);

set.addListener(new Animator.AnimatorListener() {

@Override

public void onAnimationStart(Animator animation) {

}

@Override

public void onAnimationEnd(Animator animation) {

//设置贝塞尔曲线移动效果

ValueAnimator va = getBzierAnimator(imageView);//第二部分动画

va.start();

}

@Override

public void onAnimationCancel(Animator animation) {

}

@Override

public void onAnimationRepeat(Animator animation) {

}

});

set.start();

}

//初始化贝塞尔曲线的4个点

private void initPointF() {

mPointF0 = new PointF(mScreenWidth - 60 - 50, mScreenHeight - 60 - 50);//起点是初始化时的点

mPointF1 = new PointF(mRandom.nextInt(mScreenWidth), mRandom.nextInt((int) mPointF0.y));//第一个控制点必须要在起始点的上方

mPointF2 = new PointF(mRandom.nextInt(mScreenWidth), mRandom.nextInt((int) mPointF1.y));//第二个控制点必须在第一个点的上方

mPointF3 = new PointF(mRandom.nextInt(mScreenWidth), -50);//终点在屏幕的最顶部0-图片的高度

}

/**

* 自定义估值器计算图片移动的轨迹

* 计算公式参考贝塞尔曲线3阶计算公式

* 自定义估值器的方法可百度搜索

* 其中估值器定义返回的结果为PointF

*/

public class BezierEvaluator implements TypeEvaluator {

private PointF pointF1, pointF2;

public BezierEvaluator(PointF p1, PointF p2) {

this.pointF1 = p1;

this.pointF2 = p2;

}

@Override

public PointF evaluate(float t, PointF p0, PointF p3) {

PointF point = new PointF();

point.x = p0.x * (1 - t) * (1 - t) * (1 - t) //

+ 3 * pointF1.x * t * (1 - t) * (1 - t)//

+ 3 * pointF2.x * t * t * (1 - t)//

+ p3.x * t * t * t;//

point.y = p0.y * (1 - t) * (1 - t) * (1 - t) //

+ 3 * pointF1.y * t * (1 - t) * (1 - t)//

+ 3 * pointF2.y * t * t * (1 - t)//

+ p3.y * t * t * t;//

return point;

}

}

private ValueAnimator getValueAnimator(final ImageView imageView) {

initPointF();

BezierEvaluator bezierEvaluator = new BezierEvaluator(mPointF1, mPointF2);

ValueAnimator valueAnimator = ValueAnimator.ofObject(bezierEvaluator, mPointF0, mPointF3);

valueAnimator.setDuration(3000);

valueAnimator.setTarget(imageView);

valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

@Override

public void onAnimationUpdate(ValueAnimator animation) {

//改变imageview位置实现移动效果

PointF point = (PointF) animation.getAnimatedValue();

imageView.setX(point.x);

imageView.setY(point.y);

imageView.setAlpha(1 - animation.getAnimatedFraction());

//动画结束移除imageview

if (animation.getAnimatedFraction() >= 1) {

removeView(imageView);

}

}

});

return valueAnimator;

}

/**

* 贝塞尔动画

* */

private ValueAnimator getBzierAnimator(final ImageView iv) {

// TODO Auto-generated method stub

PointF[] PointFs = getPointFs(iv); // 4个点的坐标

BezierEvaluator evaluator = new BezierEvaluator(PointFs[1], PointFs[2]);

ValueAnimator valueAnim = ValueAnimator.ofObject(evaluator, PointFs[0], PointFs[3]);

valueAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

@Override

public void onAnimationUpdate(ValueAnimator animation) {

// TODO Auto-generated method stub

PointF p = (PointF) animation.getAnimatedValue();

iv.setX(p.x);

iv.setY(p.y);

iv.setAlpha(1- animation.getAnimatedFraction()); // 透明度

//动画结束移除imageview

if (animation.getAnimatedFraction() >= 1) {

removeView(iv);

}

}

});

valueAnim.setTarget(iv);

valueAnim.setDuration(3000);

valueAnim.setInterpolator(interpolators[new Random().nextInt(4)]);

return valueAnim;

}

private PointF[] getPointFs(ImageView iv) {

// TODO Auto-generated method stub

PointF[] PointFs = new PointF[4];

PointFs[0] = new PointF(); // p0

PointFs[0].x = (mScreenWidth- layoutParams.width)/ 2;

PointFs[0].y = mScreenHeight - layoutParams.height;

PointFs[1] = new PointF(); // p1

PointFs[1].x = new Random().nextInt(mScreenWidth);

PointFs[1].y = new Random().nextInt(mScreenHeight /2) + mScreenHeight / 2 + layoutParams.height;

PointFs[2] = new PointF(); // p2

PointFs[2].x = new Random().nextInt(mScreenWidth);

PointFs[2].y = new Random().nextInt(mScreenHeight /2);

PointFs[3] = new PointF(); // p3

PointFs[3].x = new Random().nextInt(mScreenWidth);

PointFs[3].y = 0;

return PointFs;

}

}

2.givepraise_layout.xml

android:layout_width="match_parent"

android:layout_height="match_parent"

android:background="@android:color/darker_gray">

android:layout_width="match_parent"

android:layout_height="match_parent"/>

3.Activity 部分代码

import android.app.Activity;

import android.os.Bundle;

public class GivePraiseActivity extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.givepraise_layout);

}

}

4.估值器的运算

p0坐标：x坐标((布局的宽-心形图片宽)除以2)，y坐标(布局的高 -心形图片高)，这样获得的是顶部部水平中心点的坐标。

p1坐标：x坐标(横坐标中的随机位置)，y坐标(布局一半的高度 加上 0到一半高度范围内的随机坐标+心形的高度的一半)。这样取到的横坐标是在布局宽度之内的随机坐标，纵坐标为整个路径高度中部以上的随机坐标。

p2坐标：与p1类似，横坐标是在布局宽度之内的随机坐标，纵坐标为整个路径高度中部以下的随机坐标。

p3坐标：控件底部中心点

知道4个坐标了，那么就可以开始计算路径

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。