Android——动画

帧动画

帧动画就是很多张图片，一帧一帧的播放，形成的一个动画效果。

frame.xml

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"><itemandroid:drawable="@drawable/diqiu"android:duration="120" /><itemandroid:drawable="@drawable/huoxing"android:duration="120" /><itemandroid:drawable="@drawable/tuxing"android:duration="120" /><itemandroid:drawable="@drawable/shuixing"android:duration="120" />
</animation-list>

将其设置为background

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:id="@+id/main"android:layout_width="match_parent"android:layout_height="match_parent"android:background="@drawable/frame"tools:context=".FrameAnimationActivity"></RelativeLayout>

执行动画

    @Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_frame_animation);RelativeLayout relativeLayout = findViewById(R.id.main);AnimationDrawable anim = (AnimationDrawable) relativeLayout.getBackground();relativeLayout.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {if (flag) {anim.start();flag = false;} else {anim.stop();flag = true;}}});}

案例代码

补间动画

补间动画包括alpha（透明度）、rotate（旋转）、scale（缩放）、translate（平移）

• alpha.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"><alphaandroid:duration="2000"android:fromAlpha="0"android:toAlpha="1" />
</set>

• rotate.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"><rotateandroid:duration="2000"android:fromDegrees="0"android:pivotX="50%"android:pivotY="50%"android:toDegrees="360" />
</set>

• scale.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"><scaleandroid:duration="2000"android:fromXScale="1"android:fromYScale="1"android:pivotX="50%"android:pivotY="50%"android:toXScale="0.5"android:toYScale="0.5" />
</set>

• translate.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"><translateandroid:duration="2000"android:fromXDelta="0"android:fromYDelta="0"android:toXDelta="400"android:toYDelta="400" />
</set>

启动动画

        ImageView iv = findViewById(R.id.iv);iv.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {
//                Animation animation = AnimationUtils.loadAnimation(AlphaActivity.this, R.anim.alpha);
//                Animation animation = AnimationUtils.loadAnimation(AlphaActivity.this, R.anim.rotate);
//                Animation animation = AnimationUtils.loadAnimation(AlphaActivity.this, R.anim.scale);Animation animation = AnimationUtils.loadAnimation(AlphaActivity.this, R.anim.translate);iv.startAnimation(animation);}});

案例代码

属性动画

声明一个属性值，通过属性值的改变，达到动画的效果。

• ValueAnimator

        ValueAnimator valueAnimator = ValueAnimator.ofFloat(0f, 1f);valueAnimator.setDuration(2000);valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {@Overridepublic void onAnimationUpdate(@NonNull ValueAnimator animation) {float value = (float) animation.getAnimatedValue();Log.e("leo", "value:" + value);}});valueAnimator.start();

• ObjectAnimator

可以直接指定要控制的对象

        TextView tv = findViewById(R.id.tv);ObjectAnimator objectAnimator = ObjectAnimator.ofFloat(tv, "alpha", 0f, 1f);objectAnimator.setDuration(4000);objectAnimator.start();

监听

        objectAnimator.addListener(new Animator.AnimatorListener() {@Overridepublic void onAnimationStart(@NonNull Animator animation) {//开始}@Overridepublic void onAnimationEnd(@NonNull Animator animation) {//结束}@Overridepublic void onAnimationCancel(@NonNull Animator animation) {//取消}@Overridepublic void onAnimationRepeat(@NonNull Animator animation) {//重复}});

案例代码