（四十六）一个属性动画的经典例子（让TextView中的数值从某一个值变成0再变到另一个值）

package com.example.propertyanimation;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.TextView;

public class CustomFontPercedntTextView extends TextView {
private int percentage;

public CustomFontPercedntTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}

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

public CustomFontPercedntTextView(Context context) {
super(context);
}
public int getPercentage() {
return percentage;
}

public void setPercentage(int percentage) {
this.percentage = percentage;
setText(percentage + "%");
}

}

package com.example.propertyanimation;

import android.animation.AnimatorInflater;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.animation.PropertyValuesHolder;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.LinearInterpolator;
import android.widget.TextView;

public class MainActivity extends Activity {
private CustomFontPercedntTextView tv_percentage;

private TextView tv;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView) findViewById(R.id.tv);

}

public void click(View view) {
tv_percentage = (CustomFontPercedntTextView) this
.findViewById(R.id.cftv);

PropertyValuesHolder prvh = PropertyValuesHolder.ofInt("percentage",
30, 0, 70);
ObjectAnimator anim = ObjectAnimator.ofPropertyValuesHolder(
this.tv_percentage, prvh);
anim.setDuration(5000);
anim.setInterpolator(new LinearInterpolator());
anim.start();

AnimatorSet set = (AnimatorSet) AnimatorInflater.loadAnimator(this,
R.animator.property_animator);
set.setTarget(tv);
set.start();
}
}