属性动画(蓝球下移)

public class MyView extends View{
    private int color;
    private float radius;
    private Paint paint;
    public MyView(Context context) {
        this(context,null);
    }

    public MyView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init(context,attrs);

    }
    private void init(Context  context,AttributeSet attrs){

        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.MyView);
        color = typedArray.getColor(R.styleable.MyView_MyViewColor, Color.BLUE);
        radius = typedArray.getDimension(R.styleable.MyView_MyViewRadius,30);
        typedArray.recycle();

        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setStrokeWidth(2);
        paint.setColor(color);
        paint.setStyle(Paint.Style.FILL);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawCircle(30f,30f,radius,paint);
    }
}
public class WelcomeActivity extends AppCompatActivity {

    private MyView mv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_welcome);
        initView();
        startAnim();
    }
    private void initView(){
        mv = (MyView)findViewById(R.id.mv);
    }
    private void startAnim(){
        ObjectAnimator translationX = new ObjectAnimator().ofFloat(mv,"translationX",0,650f);
        ObjectAnimator translationY = new ObjectAnimator().ofFloat(mv,"translationY",0,1000f);

        AnimatorSet animatorSet = new AnimatorSet();
        animatorSet.playTogether(translationX,translationY);
        animatorSet.setDuration(3000);
        animatorSet.start();

        Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                Intent intent = new Intent(WelcomeActivity.this,MainActivity.class);
                startActivity(intent);
            }
        },3000);
    }
}
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="MyView">
        <attr name="MyViewColor" format="color"></attr>
        <attr name="MyViewRadius" format="dimension"></attr>
    </declare-styleable>
</resources>