Android -- Fragment动画异常Unknown animation name: objectAnimator

FragmentTransaction ft = getFragmentManager().beginTransaction();
//setCustomAnimations()必须位于replace()之前，否则效果不起所中。它的两个参数分别为enter，exit的效果。系统目前提供两个效果，分别为android.R.animator.fade_in和android.R.animator.fade_out
ft.setCustomAnimations(R.animator.slide_in_left,R.animator.slide_out_right);
ft.addToBackStack(null);
ft.replace(R.id.details,"detail");
ft.commit();

<?xml version="1.0" encoding="utf-8"?> 
<objectAnimator xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:interpolator/accelerate_decelerate" 
    android:valueFrom="-1280" 
    android:valueTo="0" 
    android:valueType="floatType" 
    android:propertyName="X" 
    android:duration="2000"  />

<?xml version="1.0" encoding="utf-8"?> 
<objectAnimator xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:interpolator/accelerate_decelerate" 
    android:valueFrom="0" 
    android:valueTo="1280" 
    android:valueType="floatType" 
    android:propertyName="X" 
    android:duration="2000" />

<?xml version="1.0" encoding="utf-8"?>  
<set xmlns:android="http://schemas.android.com/apk/res/android" >  
        <objectAnimator android:interpolator="@android:interpolator/accelerate_cubic"  
            android:valueFrom="1"  
            android:valueTo="0"  
            android:valueType="floatType"  
            android:propertyName="alpha"  
            android:duration="1000"/>  
        <objectAnimator android:interpolator="@android:interpolator/accelerate_cubic"  
            android:valueFrom="0"  
            android:valueTo="1280"  
            android:valueType="floatType"  
            android:propertyName="Y"  
            android:duration="1000"/>  
</set>

if (transitionStyle == 0) {
            return null;
        }
        
        //TypedArray attrs = mActivity.obtainStyledAttributes(transitionStyle,
        //        com.android.internal.R.styleable.FragmentAnimation);
        //int anim = attrs.getResourceId(styleIndex, 0);
        //attrs.recycle();
        
        //if (anim == 0) {
        //    return null;
        //}
        
        //return AnimatorInflater.loadAnimator(mActivity, anim);
        return null;

String  name = parser.getName();

            if (name.equals("objectAnimator")) {
                anim = loadObjectAnimator(c, attrs);
            } else if (name.equals("animator")) {
                anim = loadAnimator(c, attrs, null);
            } else if (name.equals("set")) {
                anim = new AnimatorSet();
                TypedArray a = c.obtainStyledAttributes(attrs,
                        com.android.internal.R.styleable.AnimatorSet);
                int ordering = a.getInt(com.android.internal.R.styleable.AnimatorSet_ordering,
                        TOGETHER);
                createAnimatorFromXml(c, parser, attrs, (AnimatorSet) anim,  ordering);
                a.recycle();
            } else {
                throw new RuntimeException("Unknown animator name: " + parser.getName());
            }

private static ObjectAnimator loadObjectAnimator(Context context, AttributeSet attrs)
            throws NotFoundException {

        ObjectAnimator anim = new ObjectAnimator();

        loadAnimator(context, attrs, anim);

        TypedArray a =
                context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.PropertyAnimator);

        String propertyName = a.getString(com.android.internal.R.styleable.PropertyAnimator_propertyName);

        anim.setPropertyName(propertyName);

        a.recycle();

        return anim;
    }