Android--自定义属性在系统控件上的用法

<com.aruba.animationlibrary.AnimatorScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:discrollve="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.aruba.animationlibrary.AnimatorLinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="600dp"
            android:scaleType="centerCrop"
            android:src="@mipmap/tb_bg" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="200dp"
            android:background="#007788"
            android:fontFamily="serif"
            android:gravity="center"
            android:padding="25dp"
            android:text="带上您的行李箱，准备shopping！"
            android:textColor="@android:color/black"
            android:textSize="25sp"
            discrollve:discrollve_alpha="true" />

        <ImageView
            android:layout_width="200dp"
            android:layout_height="120dp"
            android:layout_gravity="top|right"
            android:src="@mipmap/baggage"
            discrollve:discrollve_alpha="true"
            discrollve:discrollve_translation="fromLeft|fromBottom" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="200dp"
            android:fontFamily="serif"
            android:gravity="center"
            android:padding="25dp"
            android:text="准备好相机，这里有你想象不到的惊喜！"
            android:textColor="@android:color/black"
            android:textSize="25sp"
            discrollve:discrollve_fromBgColor="#ffff00"
            discrollve:discrollve_toBgColor="#88EE66" />

        <ImageView
            android:layout_width="220dp"
            android:layout_height="110dp"
            android:layout_gravity="right"
            android:src="@mipmap/camera"
            discrollve:discrollve_translation="fromRight" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#D97C1F"
            android:fontFamily="serif"
            android:gravity="center"
            android:padding="20dp"
            android:text="这次淘宝造物节真的来了，我们都在造，你造吗？\n
                            7月22日-7月24日\n
                            上海世博展览馆\n
                            在现场，我们造什么？"
            android:textSize="23sp"
            discrollve:discrollve_alpha="true"
            discrollve:discrollve_translation="fromBottom" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="20dp"
            android:src="@mipmap/sweet"
            discrollve:discrollve_scaleX="true"
            discrollve:discrollve_scaleY="true" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="20dp"
            android:src="@mipmap/shoes"
            discrollve:discrollve_alpha="true"
            discrollve:discrollve_scaleX="true"
            discrollve:discrollve_scaleY="true"
            discrollve:discrollve_translation="fromLeft|fromBottom" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="20dp"
            android:src="@mipmap/shoes"
            discrollve:discrollve_alpha="true"
            discrollve:discrollve_scaleY="true"
            discrollve:discrollve_translation="fromRight|fromTop" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="20dp"
            android:src="@mipmap/sweet"
            discrollve:discrollve_alpha="true"
            discrollve:discrollve_scaleY="true"
            discrollve:discrollve_translation="fromLeft" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="20dp"
            android:src="@mipmap/camera"
            discrollve:discrollve_scaleY="true"
            discrollve:discrollve_translation="fromLeft" />

    </com.aruba.animationlibrary.AnimatorLinearLayout>

</com.aruba.animationlibrary.AnimatorScrollView>

/**
 * 自定义动画框架使用的LinearLayout
 */
public class AnimatorLinearLayout extends LinearLayoutCompat {

    public AnimatorLinearLayout(Context context) {
        this(context, null);
    }

    public AnimatorLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        setOrientation(VERTICAL);
    }

    /**
     * 解析自定义属性，并记录下来，用于之后addView使用
     *
     * @param attrs
     * @return
     */
    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new MyLayoutParams(getContext(), attrs);
    }

    /**
     * 干预Activity启动过程中xml解析，偷梁换柱使用自定义动画组件包裹
     *
     * @param child
     * @param params
     */
    @Override
    public void addView(View child, ViewGroup.LayoutParams params) {
        MyLayoutParams p = (MyLayoutParams) params;
        if (!isDiscrollvable(p)) {
            super.addView(child, params);
        } else {
            //将原始child中的属性给AnimatorFrameLayout用
            AnimatorFrameLayout animatorFrameLayout = new AnimatorFrameLayout(getContext());
            animatorFrameLayout.setmDiscrollveAlpha(p.mDiscrollveAlpha);
            animatorFrameLayout.setmDiscrollveFromBgColor(p.mDiscrollveFromBgColor);
            animatorFrameLayout.setmDiscrollveToBgColor(p.mDiscrollveToBgColor);
            animatorFrameLayout.setmDiscrollveScaleX(p.mDiscrollveScaleX);
            animatorFrameLayout.setmDisCrollveTranslation(p.mDisCrollveTranslation);
            animatorFrameLayout.setmDiscrollveScaleY(p.mDiscrollveScaleY);
            //使得child成为AnimatorFrameLayout的子View
            animatorFrameLayout.addView(child);

            //将AnimatorFrameLayout添加到AnimatorLinearLayout中
            super.addView(animatorFrameLayout, params);
        }
    }

    private boolean isDiscrollvable(MyLayoutParams p) {
        return p.mDiscrollveAlpha ||
                p.mDiscrollveScaleX ||
                p.mDiscrollveScaleY ||
                p.mDisCrollveTranslation != -1 ||
                (p.mDiscrollveFromBgColor != -1 &&
                        p.mDiscrollveToBgColor != -1);
    }

    public class MyLayoutParams extends LinearLayoutCompat.LayoutParams {
        public int mDiscrollveFromBgColor;//背景颜色变化开始值
        public int mDiscrollveToBgColor;//背景颜色变化结束值
        public boolean mDiscrollveAlpha;//是否需要透明度动画
        public int mDisCrollveTranslation;//平移值
        public boolean mDiscrollveScaleX;//是否需要x轴方向缩放
        public boolean mDiscrollveScaleY;//是否需要y轴方向缩放

        public MyLayoutParams(Context c, AttributeSet attrs) {
            super(c, attrs);
            //解析attrs得到自定义的属性，保存
            TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.DiscrollView_LayoutParams);
            mDiscrollveAlpha = a.getBoolean(R.styleable.DiscrollView_LayoutParams_discrollve_alpha, false);
            mDiscrollveScaleX = a.getBoolean(R.styleable.DiscrollView_LayoutParams_discrollve_scaleX, false);
            mDiscrollveScaleY = a.getBoolean(R.styleable.DiscrollView_LayoutParams_discrollve_scaleY, false);
            mDisCrollveTranslation = a.getInt(R.styleable.DiscrollView_LayoutParams_discrollve_translation, -1);
            mDiscrollveFromBgColor = a.getColor(R.styleable.DiscrollView_LayoutParams_discrollve_fromBgColor, -1);
            mDiscrollveToBgColor = a.getColor(R.styleable.DiscrollView_LayoutParams_discrollve_toBgColor, -1);
            a.recycle();
        }
    }

}