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，家裡估計會沒網，更完這篇的話，可能要到年後了，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，准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<喎?/kf/ware/vc/" target="_blank" class="keylink">vc3Ryb25nPjxiciAvPg0KCde8sbi5pNf3vs3Kx9e8sbjNvMasv6k8L3A+DQo8L2Jsb2NrcXVvdGU+DQo8aDIgaWQ9"bezierevaluator">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 {

    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();// 先加速後減速
    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 用於後面的計算
        // 注意 我這裡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 並且 水平居中
        lp = new LayoutParams(dWidth, dHeight);
        lp.addRule(CENTER_HORIZONTAL, TRUE);// 這裡的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));

        // 這裡最好畫個圖 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) {
            // 這裡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);
            // 這裡順便做一個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動畫結束後remove掉
            removeView((target));
        }
    }
}

activity_main.xml

布局的實現

<code class=" hljs avrasm"><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">

    </relativelayout></code><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！"><code class=" hljs avrasm">

    <com.lgl.heartfaom.periscopelayout android:id="@+id/periscope" android:layout_width="match_parent" android:layout_height="match_parent">
    </com.lgl.heartfaom.periscopelayout>

</code></button>

MainActivity

接著就是怎麼去使用它了

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！