21.property animation 属性动画

一、ValueAnimator

1.获取value对应的值

2.设置监听，获取监听的过程

3.启动动画

4.实现步骤

5.总体代码

package com.example.myvalueanimator;
import androidx.appcompat.app.AppCompatActivity;
import android.animation.ValueAnimator;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ValueAnimator valueAnimator = ValueAnimator.ofFloat(1f, 2f);
        valueAnimator.setDuration(2000);
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                float value = (float) animation.getAnimatedValue();
                Log.e("he","onAnimationUpdate: "+value);
            }
        });
        valueAnimator.start();
    }
}

6.效果图

二、ObjectAnimator

1.实现步骤

2.总体代码

package com.example.myvalueanimator;
import androidx.appcompat.app.AppCompatActivity;
import android.animation.ObjectAnimator;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TextView textview = findViewById(R.id.tv_one);
        //对控件进行透明度从0到1的变化
        ObjectAnimator objectAnimator = ObjectAnimator.ofFloat(textview, "alpha", 0f, 1f);
        objectAnimator.setDuration(6000);
        objectAnimator.start();
    }
}

3.效果图

三、监听器

1.onAnimationStart() 动画开始的时候调用

2.onAnimationEnd() 动画结束的时候调用

3.onAnimationCancel() 动画被取消的时候调用

4.onAnimationRepeat() 动画重复执行的时候调用

5.实现步骤

6.总体代码

package com.example.myvalueanimator;
import androidx.appcompat.app.AppCompatActivity;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TextView textview = findViewById(R.id.tv_one);
        //对控件进行透明度从0到1的变化
        ObjectAnimator objectAnimator = ObjectAnimator.ofFloat(textview, "alpha", 0f, 1f);
        objectAnimator.setDuration(6000);
        objectAnimator.start();
        objectAnimator.addListener(new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation) {
            }
            @Override
            public void onAnimationEnd(Animator animation) {
            }
            @Override
            public void onAnimationCancel(Animator animation) {
            }
            @Override
            public void onAnimationRepeat(Animator animation) {
            }
        });
        //适配的方式
        objectAnimator.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationStart(Animator animation) {
                super.onAnimationStart(animation);
            }
        });
    }
}