android 根据滑动隐藏或显示导航 类似手机QQ好友个人信息

//重写ScrollView





public class NotifyingScrollView extends ScrollView {

     /**

     * @author Cyril Mottier

     */

    public interface OnScrollChangedListener {

        void onScrollChanged(ScrollView who, int l, int t, int oldl, int oldt);

    }



    private OnScrollChangedListener mOnScrollChangedListener;



    public NotifyingScrollView(Context context) {

        super(context);

    }



    public NotifyingScrollView(Context context, AttributeSet attrs) {

        super(context, attrs);

    }



    public NotifyingScrollView(Context context, AttributeSet attrs, int defStyle) {

        super(context, attrs, defStyle);

    }



    @Override

    protected void onScrollChanged(int l, int t, int oldl, int oldt) {

        super.onScrollChanged(l, t, oldl, oldt);

        if (mOnScrollChangedListener != null) {

            mOnScrollChangedListener.onScrollChanged(this, l, t, oldl, oldt);

        }

    }



    public void setOnScrollChangedListener(OnScrollChangedListener listener) {

        mOnScrollChangedListener = listener;

    }



}

View Code

布局引用重写NotifyingScrollView控件

 <你的项目路径.NotifyingScrollView

            android:id="@id/sv_personal"

            android:layout_width="match_parent"

            android:layout_height="match_parent"

            android:background="@color/layout_bg"

            android:scrollbars="none" >

    

 <LinearLayout

                android:layout_width="match_parent"

                android:layout_height="wrap_content"

                android:background="@color/layout_bg"

                android:orientation="vertical" >

你要显示的内容

</LinearLayout>

        </你的项目路径.NotifyingScrollView>

View Code

activity使用引用

NotifyingScrollView sv_personal=(NotifyingScrollView)findViewById(R.id.sv_personal);

sv_personal.setOnScrollChangedListener(mOnScrollChangedListener);







private NotifyingScrollView.OnScrollChangedListener mOnScrollChangedListener = new NotifyingScrollView.OnScrollChangedListener() {

public void onScrollChanged(ScrollView who, int l, int t, int oldl, int oldt) {

int Height=Utility.dip2px(context, 130);

float ratio =Math.max(Math.min(1, t/Height), 0);

//导航控件

linar_top.setAlpha(ratio* 255);

}

};

View Code

 int Height=Utility.dip2px(context, 130); 130为要滑动的高度