android-卡片旋转特效

 直接看图:

实现此功能，会用到属性动画；

但是具体做起来，有两种途径：

1）纯java代码来写：

package com.example.cardrotation;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.FrameLayout;

/**
 * 旋转卡片特效
 * 第1种写法
 * <p>
 * 用纯java代码来写动画特效以及 执行动画
 */
public class MainActivity2 extends AppCompatActivity {

    private FrameLayout mFlCardBack, mFlCardFront, mFlContainer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mFlCardBack = findViewById(R.id.fl_back);
        mFlCardFront = findViewById(R.id.fl_front);
        mFlContainer = findViewById(R.id.main_fl_container);
        mFlContainer.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                flipCard();
            }
        });

        initAnimatorSet();
        setCameraDistance(); // 设置镜头距离
    }

    // 改变视角距离, 贴近屏幕,这个必须设置，因为如果不这么做，沿着Y轴旋转的过程中有可能产生超出屏幕的3D效果。
    private void setCameraDistance() {
        int distance = 16000;
        float scale = getResources().getDisplayMetrics().density * distance;
        mFlCardFront.setCameraDistance(scale);
        mFlCardBack.setCameraDistance(scale);
    }

    private boolean mIsShowBack = false;

    // 翻转卡片
    public void flipCard() {
        // 正面朝上
        if (!mIsShowBack) {
            inSet.setTarget(mFlCardBack);
            outSet.setTarget(mFlCardFront);
            mIsShowBack = true;
        } else { // 背面朝上
            inSet.setTarget(mFlCardFront);
            outSet.setTarget(mFlCardBack);
            mIsShowBack = false;
        }
        inSet.start();
        outSet.start();
    }

    AnimatorListenerAdapter animatorListenerAdapter = new AnimatorListenerAdapter() {
        @Override
        public void onAnimationStart(Animator animation) {
            super.onAnimationStart(animation);
            mFlContainer.setClickable(false);//在动画执行过程中，不许允许接收点击事件
        }

        @Override
        public void onAnimationEnd(Animator animation) {
            super.onAnimationEnd(animation);
            mFlContainer.setClickable(true);//在动画执行过程中，不许允许接收点击事件
        }
    };

    private AnimatorSet inSet, outSet;

    private void initAnimatorSet() {
        inSet = new AnimatorSet();
        ObjectAnimator animator = ObjectAnimator.ofFloat(null, "rotationY", -180f, 0f);
        animator.setDuration(500);
        animator.setStartDelay(0);
        ObjectAnimator animator2 = ObjectAnimator.ofFloat(null, "alpha", 0.0f, 1f);
        animator2.setStartDelay(250);
        animator2.setDuration(0);
        inSet.playTogether(animator, animator2);
        inSet.addListener(animatorListenerAdapter);

        outSet = new AnimatorSet();
        ObjectAnimator animator_ = ObjectAnimator.ofFloat(null, "rotationY", 0, 180f);
        animator_.setDuration(500);
        animator_.setStartDelay(0);
        ObjectAnimator animator2_ = ObjectAnimator.ofFloat(null, "alpha", 1f, 0f);
        animator2_.setStartDelay(250);
        animator2_.setDuration(0);
        outSet.playTogether(animator_, animator2_);
        outSet.addListener(animatorListenerAdapter);
    }

}

2) 用 animator.xml来配置动画特效，然后在java代码中执行动画

package com.example.cardrotation;

import android.animation.Animator;
import android.animation.AnimatorInflater;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.FrameLayout;

/**
 * 旋转卡片特效
 * 第2种写法
 *
 * 用animator.xml的配置来描述动画特效
 * 在代码中，执行动画
 *
 */
public class MainActivity extends AppCompatActivity {

    private FrameLayout mFlCardBack, mFlCardFront, mFlContainer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mFlCardBack = findViewById(R.id.fl_back);
        mFlCardFront = findViewById(R.id.fl_front);
        mFlContainer = findViewById(R.id.main_fl_container);
        mFlContainer.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                flipCard();
            }
        });

        initAnimatorSet(); // 设置动画
        setCameraDistance(); // 设置镜头距离
    }

    // 改变视角距离, 贴近屏幕,这个必须设置，因为如果不这么做，沿着Y轴旋转的过程中有可能产生超出屏幕的3D效果。
    private void setCameraDistance() {
        int distance = 16000;
        float scale = getResources().getDisplayMetrics().density * distance;
        mFlCardFront.setCameraDistance(scale);
        mFlCardBack.setCameraDistance(scale);
    }

    private boolean mIsShowBack = false;

    // 翻转卡片
    public void flipCard() {
        // 正面朝上
        if (!mIsShowBack) {
            mRightOutSet.setTarget(mFlCardFront);
            mLeftInSet.setTarget(mFlCardBack);
            mIsShowBack = true;
        } else { // 背面朝上
            mRightOutSet.setTarget(mFlCardBack);
            mLeftInSet.setTarget(mFlCardFront);
            mIsShowBack = false;
        }
        mRightOutSet.start();
        mLeftInSet.start();
    }

    private AnimatorSet mRightOutSet, mLeftInSet;
    AnimatorListenerAdapter animatorListenerAdapter = new AnimatorListenerAdapter() {
        @Override
        public void onAnimationStart(Animator animation) {
            super.onAnimationStart(animation);
            mFlContainer.setClickable(false);//在动画执行过程中，不许允许接收点击事件
        }

        @Override
        public void onAnimationEnd(Animator animation) {
            super.onAnimationEnd(animation);
            mFlContainer.setClickable(true);//在动画执行过程中，不许允许接收点击事件
        }
    };


    private void initAnimatorSet() {
        mRightOutSet = (AnimatorSet) AnimatorInflater.loadAnimator(this, R.animator.anim_out);
        mLeftInSet = (AnimatorSet) AnimatorInflater.loadAnimator(this, R.animator.anim_in);

        // 设置点击事件
        mRightOutSet.addListener(animatorListenerAdapter);
        mLeftInSet.addListener(animatorListenerAdapter);
    }
}

这里用到了xml配置，所以必须在res中写xml

下面贴出anim_in.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <!-- 这里做个说明- 用XML来配置动画效果，下面这种平行的写法其实是让旋转，和透明动画 同时执行，
    startOffset是执行延时，对应ObjectAnimator的 setStartDelay(long startDelay) 方法 -->

    <!--旋转-->
    <objectAnimator
        android:duration="500"
        android:propertyName="rotationY"
        android:valueFrom="-180"
        android:valueTo="0" />

    <!--出现-->
    <objectAnimator
        android:duration="0"
        android:propertyName="alpha"
        android:startOffset="250"
        android:valueFrom="0.0"
        android:valueTo="1.0" />
    <!-- 所以说这个startOffSet的意思就是，这个动画延迟多久ms以后执行 -->
</set>

和anim_out.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <!--旋转-->
    <objectAnimator
        android:duration="500"
        android:propertyName="rotationY"
        android:valueFrom="0"
        android:valueTo="180" />

    <!--消失-->
    <objectAnimator
        android:duration="0"
        android:propertyName="alpha"
        android:startOffset="250"
        android:valueFrom="1.0"
        android:valueTo="0.0" />
</set>

OK，关键代码上面已经给出。

下面是公共部分布局的代码：

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_fl_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <include layout="@layout/cell_card_back" />

    <include layout="@layout/cell_card_front" />

</FrameLayout>

　　

卡片反面cell_card_back.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/fl_back"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="20dp">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/colorPrimary"
        android:gravity="center"
        android:text="反面"
        android:textColor="@color/colorAccent"
        android:textSize="30sp" />

</FrameLayout>

卡片正面 cell_card_front.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="20dp"
    android:id="@+id/fl_front">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/darker_gray"
        android:gravity="center"
        android:text="正面"
        android:textColor="@color/colorPrimary"
        android:textSize="30sp" />
</FrameLayout>

OK，完事。

所有的动画特效基本都有这两种写法。

具体用什么，看心情吧。 

用纯java，可能api查起来方便一点，毕竟xml写配置，不能alt点进去看属性说明。

用xml的话，可能在代码端就简洁一点，属性，自己想办法上网查好了。

就这样了·····