Android之补间动画和属性动画

属性动画

• ValueAnimator
• ObjectAnimator.ofFloat()

ObjectAnimActivity

package com.example.test0508;

import androidx.appcompat.app.AppCompatActivity;

import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class ObjectAnimActivity extends AppCompatActivity {

    private TextView tvTest;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_object_anim);
        tvTest = findViewById(R.id.tv_ani_text);

        //属性动画
        //平移
        //tvTest.animate().translationYBy(500).setDuration(2000).start();

        //渐变为透明
        //tvTest.animate().alpha(0).setDuration(3000).start();

        ValueAnimator valueAnimator = ValueAnimator.ofInt(0,100);
        valueAnimator.setDuration(2000);
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                //实际的值
                Log.d("aaaa",valueAnimator.getAnimatedValue()+"");
                //其实是一个动画的进度0-1
                Log.d("aaaa",valueAnimator.getAnimatedFraction()+"");
            }
        });
        valueAnimator.start();


        /**
         * ObjectAnimator用法
         */
         //向下平移 0 到 500 再到200
        ObjectAnimator objectAnimator = ObjectAnimator.ofFloat(tvTest,"translationY",0,500,200);
        objectAnimator.setDuration(2500).start();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ObjectAnimActivity"
    android:orientation="vertical"
    >

    <TextView
        android:id="@+id/tv_ani_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:gravity="center"
        android:text="动画测试"
        android:textColor="#ffffff"
        android:background="#000000"
        />


</LinearLayout>

补间动画是视觉现象并没有真正改变view的值（不变位置）
属性动画是改变了view的值了（变位置了）