ValueAnimator.ofObject的使用

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/btn"
android:text="开始"/>

<www.weshared.anim.PointView
android:id="@+id/ponitview"
android:layout_width="200dp"
android:layout_height="200dp"
android:background="@android:color/transparent"
android:layout_centerInParent="true" />

</RelativeLayout>

public class PointView extends TextView {

private Paint mPaint;
private int mColor = Color.TRANSPARENT;
private Point point;
private boolean isFirst;

public PointView(Context context) {
super(context);
init();
}

public PointView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}

public PointView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}

/**
* 初始化画笔，设置颜色为蓝色
*/
private void init() {
mColor = Color.CYAN;
mPaint = new Paint();
//抗锯齿
mPaint.setAntiAlias(true);
mPaint.setColor(mColor);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int height = getHeight();
int width = getWidth();
int initR = Math.min(width, height) / 2;
if (!isFirst) {
//初始化点
point = new Point(initR);
isFirst = true;
}
//画圆
canvas.drawCircle(width / 2, height / 2, point.getR(), mPaint);
}

public void showCharAnim() {
ValueAnimator animator = ValueAnimator.ofObject(new CharEvaluator(), new Character('A'), new Character('z'));
animator.setDuration(5000).start();
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
char animatedValue = (char) animation.getAnimatedValue();
//将文字展示到控件上
PointView.this.setText(String.valueOf(animatedValue));
PointView.this.setTextSize(30);
PointView.this.setTextColor(Color.RED);
invalidate();
}
});
}

public void showColorAnim(){
ValueAnimator animator = ValueAnimator.ofArgb(0xFFFF0000, 0xFF0000FF, 0xFFFF0000, 0xFF0000FF);
animator.setDuration(5000).start();
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
int animatedValue = (int) animation.getAnimatedValue();
PointView.this.setTextColor(animatedValue);
invalidate();
}
});
}

public void showPointAnim() {
float width = getMeasuredWidth();
float height = getMeasuredHeight();
float r = Math.min(width, height) / 2;

//用ObjectAnimator也可以实现，不过和属性值无关了，ObjectAnimator是ValueAnimator的子类，实际上还是通过addUpdateListener执行了ValueAnimator动画
//        ObjectAnimator animator = ObjectAnimator.ofObject(this, "---", new PointEvaluator(), new Point(r * 0.1f), new Point(r * 1.2f), new Point(r * 0.3f), new Point(r));
ValueAnimator animator = ValueAnimator.ofObject(new PointEvaluator(), new Point(r), new Point(r * 0.2f), new Point(r * 1.2f), new Point(r * 0.2f), new Point(r));
animator.setInterpolator(new OvershootInterpolator());
animator.setDuration(5000).start();
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
point = (Point) animation.getAnimatedValue();
invalidate();
}
});
}

public class PointEvaluator implements TypeEvaluator<Point> {

@Override
public Point evaluate(float fraction, Point startValue, Point endValue) {
//拿到point的半径值
float startValueR = startValue.getR();
float endValueR = endValue.getR();
float currentValueR = startValueR + (endValueR - startValueR) * fraction;
return new Point(currentValueR);
}
}

public class CharEvaluator implements TypeEvaluator<Character> {

@Override
public Character evaluate(float fraction, Character startValue, Character endValue) {

int start = startValue;
int end = endValue;
char current = (char) (start + (end - start) * fraction);
return current;
}
}
}

public class AnimActivity extends AppCompatActivity {

private Button mButton;
private PointView mPonitView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
initView();
initListener();
}

private void initView() {
setContentView(R.layout.activity_anim);
mButton = (Button) findViewById(R.id.btn);
mPonitView = (PointView) findViewById(R.id.ponitview);
}

private void initListener() {
mButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mPonitView.showPointAnim();
mPonitView.showCharAnim();
mPonitView.showColorAnim();
}
});
}
}

public class Point {

public float r;
public float x;
public float y;

public Point(float r){
this.r=r;
}

public Point(float x, float y,float r){
this.x=x;
this.y=y;
this.r=r;
}

public void setR(float r) {
this.r = r;
}

public void setX(float x) {
this.x = x;
}

public void setY(float y) {
this.y = y;
}

public float getR() {
return r;
}

public float getX() {
return x;
}

public float getY() {
return y;
}
}