属性动画入门学习

package com.loaderman.customviewdemo;

import android.animation.ValueAnimator;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private TextView tv;
    private Button btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tv = (TextView) findViewById(R.id.tv);

        btn = (Button) findViewById(R.id.btn);
        btn.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                doAnimation();
            }
        });

        tv.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "clicked me", Toast.LENGTH_SHORT).show();
            }
        });
    }
    private void doAnimation(){
        ValueAnimator animator = ValueAnimator.ofInt(0,400);//从屏幕的左上角(0,0)到屏幕(400,400)
        animator.setDuration(1000);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            public void onAnimationUpdate(ValueAnimator animation) {
                int curValue = (Integer)animation.getAnimatedValue();
                tv.layout(curValue,curValue,curValue+tv.getWidth(),curValue+tv.getHeight());
            }
        });
        animator.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"
    android:orientation="vertical"
    tools:context="com.loaderman.customviewdemo.MainActivity">

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:text="start anim"
        />
    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:background="#ffff00"
        android:text="Hello"/>


</LinearLayout>