ScrollView增加标题并且控制显示和隐藏

标签：scrollerview   scroller   view   滑动   

转载请著名出处: http://blog.csdn.net/forwardyzk/article/details/46636997

我们知道XLIstview有上拉刷新和下拉加载,现在模拟一下XlistView的下拉刷新,使Scroller也有标题,通过滑动控制标题的显示和隐藏.

我们先来看一下效果:

首先创建标题View

scroller_header.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/darker_gray">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:gravity="center_vertical"
        android:text="我是第一个孩子"
        android:textSize="25sp" />
</LinearLayout>

public class ScrollHeader extends LinearLayout {
    private LinearLayout mContainer;
    private Context mContext;

    public ScrollHeader(Context context, AttributeSet attrs) {
        super(context, attrs);
        mContext = context;
        initView();
    }

    private void initView() {
        // 初始情况
        LayoutParams lp = new LayoutParams(
                android.view.ViewGroup.LayoutParams.FILL_PARENT, 0);
        mContainer = (LinearLayout) LayoutInflater.from(mContext).inflate(
                R.layout.scroller_header, null);

        addView(mContainer, lp);
        setGravity(Gravity.BOTTOM);
    }


    /**
     * 设置显示的高度
     *
     * @param height
     */
    public void setVisiableHeight(int height) {
        if (height < 0)
            height = 0;
        LayoutParams lp = (LayoutParams) mContainer
                .getLayoutParams();
        lp.height = height;
        mContainer.setLayoutParams(lp);
    }

    /**
     * 获取显示的高度
     *
     * @return
     */
    public int getVisiableHeight() {
        return mContainer.getHeight();
    }
}

setVisiableHeight动态设置标题的高度

getVisiableHeight获取标题的高度

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <com.example.yang.listviewtitle.view.MyScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <com.example.yang.listviewtitle.view.ScrollHeader
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第2个孩子" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第3个孩子" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第4个孩子" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第5个孩子" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第6个孩子" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第7个孩子" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第8个孩子" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第9个孩子" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:layout_marginBottom="10dp"
                android:background="@android:color/holo_blue_dark"
                android:gravity="center_vertical"
                android:padding="10dp"
                android:text="我是第10个孩子" />

        </LinearLayout>


    </com.example.yang.listviewtitle.view.MyScrollView>

</LinearLayout>

1.MyScrllerView的子View是Linearlayout,如果要换成其他的布局,要在代码中做相应的改变

2.要把自定义的标题作为MyScrllerView子View的第一个子View. 

自定义MyScrollerView

public class MyScrollView extends ScrollView {
    private ScrollHeader mHeader;
    private float mLastY = -1;
    private Context mContext;
    private int MAX_VISI_HEIGHT;
    private Scroller mScroller;

    public MyScrollView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mContext = context;
        MAX_VISI_HEIGHT = getScreenHeight() / 3;
        mScroller = new Scroller(context, new DecelerateInterpolator());

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //获取Scroller的第一个孩子,就是包裹所有孩子的View
        LinearLayout firstLL = (LinearLayout) getChildAt(0);
        mHeader = (ScrollHeader) firstLL.getChildAt(0);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (mLastY == -1) {
            mLastY = ev.getRawY();
        }
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mLastY = ev.getRawY();
                break;
            case MotionEvent.ACTION_MOVE:
                final float deltaY = ev.getRawY() - mLastY;
                mLastY = ev.getRawY();
                if (deltaY > 0) {
                    int height = mHeader.getVisiableHeight();
                    if (MAX_VISI_HEIGHT > height) {
                        //更新header高度
                        mHeader.setVisiableHeight((int) deltaY + height);
                    }

                }

                break;
            case MotionEvent.ACTION_UP:
                Log.d("MyScrollerView", "MOVE_UP");
                if (mHeader.getVisiableHeight() > 0) {
                    resetHeaderHeight();
                }


                break;
        }
        return super.onTouchEvent(ev);
    }

    /**
     * 获取屏幕的高度
     *
     * @return
     */
    private int getScreenHeight() {
        WindowManager windowManager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics displayMetrics = new DisplayMetrics();
        windowManager.getDefaultDisplay().getMetrics(displayMetrics);
        return displayMetrics.heightPixels;
    }

    private void resetHeaderHeight() {
        int height = mHeader.getVisiableHeight();
        Log.d("MyScrollerView", "移动的高度:" + (0 - height));
        mScroller.startScroll(0, height, 0, 0 - height,
                400);
        invalidate();
    }

    @Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            mHeader.setVisiableHeight(mScroller.getCurrY());
            postInvalidate();
        }
        super.computeScroll();
    }
}

1.获取到不局文件中的标题View

2.通过监听滑动ScrllerView手势,如果是向下拉,那么计算出滑动的距离,

3.讲滑动的距离来移动标题View

4.当手离开了屏幕,那么使用Scroller来平移标题View到初始的位置

在onMeasure中获取要操作的标题View

//获取Scroller的第一个孩子,就是包裹所有孩子的View
        LinearLayout firstLL = (LinearLayout) getChildAt(0);
        mHeader = (ScrollHeader) firstLL.getChildAt(0);

在onTouchEvent的MotionEvent.MOVE_UP:设置标题的回到初始的位置

 mScroller.startScroll(0, height, 0, 0 - height,
                400);
        invalidate();

@Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            mHeader.setVisiableHeight(mScroller.getCurrY());
            postInvalidate();
        }
        super.computeScroll();
    }

回弹的时间:现在设置的400毫秒,这个时间可以根据需求来改变.

最主要的标题的显示:需更改变,只需更改scroller_header.xml布局.

到此效果已经实现.

源码下载:http://download.csdn.net/detail/forwardyzk/8838455

ScrollView增加标题并且控制显示和隐藏

标签：scrollerview   scroller   view   滑动   

原文地址：http://blog.csdn.net/forwardyzk/article/details/46636997