# Android特效專輯（八）——實現心型起泡飛舞的特效，讓你的APP瞬間暖心 * * * > 馬上也要放年假了，家里估計會沒網，更完這篇的話，可能要到年后了，不過在此期間會把更新內容都保存在本地，這樣有網就可以發表了，也是極好的，今天說的這個特效，原本是Only上的一個小彩蛋的，我們來看看圖片  > 只要我點擊了Only這個字，下面就開始上升起起泡了，這個實現起來其實就是一個欲蓋彌彰的動畫而已，準備好三張顏色不一樣的心型圖片咯，這樣的話，我們就開始動手來寫一寫吧！? > **首先新建一個工程——HeartFaom**? > 準備工作就是準備圖片咯 ## BezierEvaluator ~~~ 單位轉換以及計算軌跡 ~~~ ~~~ package com.lgl.heartfaom; import android.animation.TypeEvaluator; import android.graphics.PointF; public class BezierEvaluator implements TypeEvaluator<PointF> { private PointF pointF1; private PointF pointF2; public BezierEvaluator(PointF pointF1, PointF pointF2) { this.pointF1 = pointF1; this.pointF2 = pointF2; } @Override public PointF evaluate(float time, PointF startValue, PointF endValue) { float timeLeft = 1.0f - time; PointF point = new PointF();// 結果 point.x = timeLeft * timeLeft * timeLeft * (startValue.x) + 3 * timeLeft * timeLeft * time * (pointF1.x) + 3 * timeLeft * time * time * (pointF2.x) + time * time * time * (endValue.x); point.y = timeLeft * timeLeft * timeLeft * (startValue.y) + 3 * timeLeft * timeLeft * time * (pointF1.y) + 3 * timeLeft * time * time * (pointF2.y) + time * time * time * (endValue.y); return point; } } ~~~ ## PeriscopeLayout ~~~ 貝塞爾曲線的計算以及氣泡的實現 ~~~ ~~~ package com.lgl.heartfaom; import java.util.Random; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.animation.AnimatorSet; import android.animation.ObjectAnimator; import android.animation.ValueAnimator; import android.annotation.TargetApi; import android.content.Context; import android.graphics.PointF; import android.graphics.drawable.Drawable; import android.os.Build; 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; public class PeriscopeLayout extends RelativeLayout { private Interpolator line = new LinearInterpolator();// 線性 private Interpolator acc = new AccelerateInterpolator();// 加速 private Interpolator dce = new DecelerateInterpolator();// 減速 private Interpolator accdec = new AccelerateDecelerateInterpolator();// 先加速后減速 private Interpolator[] interpolators; private int mHeight; private int mWidth; private LayoutParams lp; private Drawable[] drawables; private Random random = new Random(); private int dHeight; private int dWidth; public PeriscopeLayout(Context context) { super(context); init(); } public PeriscopeLayout(Context context, AttributeSet attrs) { super(context, attrs); init(); } public PeriscopeLayout(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public PeriscopeLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); init(); } private void init() { // 初始化顯示的圖片 drawables = new Drawable[3]; Drawable red = getResources().getDrawable(R.drawable.pl_red); Drawable yellow = getResources().getDrawable(R.drawable.pl_yellow); Drawable blue = getResources().getDrawable(R.drawable.pl_blue); drawables[0] = red; drawables[1] = yellow; drawables[2] = blue; // 獲取圖的寬高 用于后面的計算 // 注意 我這里3張圖片的大小都是一樣的,所以我只取了一個 dHeight = red.getIntrinsicHeight(); dWidth = red.getIntrinsicWidth(); // 底部 并且 水平居中 lp = new LayoutParams(dWidth, dHeight); lp.addRule(CENTER_HORIZONTAL, TRUE);// 這里的TRUE 要注意 不是true lp.addRule(ALIGN_PARENT_BOTTOM, TRUE); // 初始化插補器 interpolators = new Interpolator[4]; interpolators[0] = line; interpolators[1] = acc; interpolators[2] = dce; interpolators[3] = accdec; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); mWidth = getMeasuredWidth(); mHeight = getMeasuredHeight(); } public void addHeart() { ImageView imageView = new ImageView(getContext()); // 隨機選一個 imageView.setImageDrawable(drawables[random.nextInt(3)]); imageView.setLayoutParams(lp); addView(imageView); Animator set = getAnimator(imageView); set.addListener(new AnimEndListener(imageView)); set.start(); } private Animator getAnimator(View target) { AnimatorSet set = getEnterAnimtor(target); ValueAnimator bezierValueAnimator = getBezierValueAnimator(target); AnimatorSet finalSet = new AnimatorSet(); finalSet.playSequentially(set); finalSet.playSequentially(set, bezierValueAnimator); finalSet.setInterpolator(interpolators[random.nextInt(4)]); finalSet.setTarget(target); return finalSet; } private AnimatorSet getEnterAnimtor(final View target) { ObjectAnimator alpha = ObjectAnimator.ofFloat(target, View.ALPHA, 0.2f, 1f); ObjectAnimator scaleX = ObjectAnimator.ofFloat(target, View.SCALE_X, 0.2f, 1f); ObjectAnimator scaleY = ObjectAnimator.ofFloat(target, View.SCALE_Y, 0.2f, 1f); AnimatorSet enter = new AnimatorSet(); enter.setDuration(500); enter.setInterpolator(new LinearInterpolator()); enter.playTogether(alpha, scaleX, scaleY); enter.setTarget(target); return enter; } private ValueAnimator getBezierValueAnimator(View target) { // 初始化一個貝塞爾計算器- - 傳入 BezierEvaluator evaluator = new BezierEvaluator(getPointF(2), getPointF(1)); // 這里最好畫個圖 理解一下 傳入了起點 和 終點 ValueAnimator animator = ValueAnimator.ofObject(evaluator, new PointF( (mWidth - dWidth) / 2, mHeight - dHeight), new PointF(random.nextInt(getWidth()), 0)); animator.addUpdateListener(new BezierListenr(target)); animator.setTarget(target); animator.setDuration(3000); return animator; } /** * 獲取中間的兩個 點 * * @param scale */ private PointF getPointF(int scale) { PointF pointF = new PointF(); pointF.x = random.nextInt((mWidth - 100));// 減去100 是為了控制 x軸活動范圍,看效果 隨意~~ // 再Y軸上 為了確保第二個點 在第一個點之上,我把Y分成了上下兩半 這樣動畫效果好一些 也可以用其他方法 pointF.y = random.nextInt((mHeight - 100)) / scale; return pointF; } private class BezierListenr implements ValueAnimator.AnimatorUpdateListener { private View target; public BezierListenr(View target) { this.target = target; } @Override public void onAnimationUpdate(ValueAnimator animation) { // 這里獲取到貝塞爾曲線計算出來的的x y值 賦值給view 這樣就能讓愛心隨著曲線走啦 PointF pointF = (PointF) animation.getAnimatedValue(); target.setX(pointF.x); target.setY(pointF.y); // 這里順便做一個alpha動畫 target.setAlpha(1 - animation.getAnimatedFraction()); } } private class AnimEndListener extends AnimatorListenerAdapter { private View target; public AnimEndListener(View target) { this.target = target; } @Override public void onAnimationEnd(Animator animation) { super.onAnimationEnd(animation); // 因為不停的add 導致子view數量只增不減,所以在view動畫結束后remove掉 removeView((target)); } } } ~~~ ## activity_main.xml ~~~ 布局的實現 ~~~ ~~~ <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#000" > <Button android:id="@+id/btn_start" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:text="飛舞吧！" /> <com.lgl.heartfaom.PeriscopeLayout android:id="@+id/periscope" android:layout_width="match_parent" android:layout_height="match_parent" > </com.lgl.heartfaom.PeriscopeLayout> </RelativeLayout> ~~~ ## MainActivity ~~~ 接著就是怎么去使用它了 ~~~ ~~~ package com.lgl.heartfaom; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; public class MainActivity extends Activity { private Button btn_start; // 心型氣泡 private PeriscopeLayout periscopeLayout; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // 初始化 periscopeLayout = (PeriscopeLayout) findViewById(R.id.periscope); btn_start = (Button) findViewById(R.id.btn_start); btn_start.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // 調用添加泡泡的方法 periscopeLayout.addHeart(); } }); } } ~~~ > 好，我們接下來就可以運行一下試試實際上的效果了  > 覺得不錯的點個贊哦！ ## Demo下載地址：[http://download.csdn.net/detail/qq_26787115/9422603](http://download.csdn.net/detail/qq_26787115/9422603)