自定義scrollview

https://github.com/emilsjolander/StickyListHeaders

https://github.com/emilsjolander/StickyScrollViewItems

用這個開源的包也可以是想我想要的效果，但是這裏沒有引用這個包，而是自己寫了自定義scrollview

1 在widget目錄中定義自定義scrollview控件

public class StickyScrollView extends ScrollView {
	private static final String STICKY = "sticky";
	private View mCurrentStickyView;
	private Drawable mShadowDrawable;
	private List<View> mStickyViews;
	private int mStickyViewTopOffset;
	private int defaultShadowHeight = 10;
	private float density;
	private boolean redirectTouchToStickyView;

	private Runnable mInvalidataRunnable = new Runnable() {

		@Override
		public void run() {
			if (mCurrentStickyView != null) {
				int left = mCurrentStickyView.getLeft();
				int top = mCurrentStickyView.getTop();
				int right = mCurrentStickyView.getRight();
				int bottom = getScrollY()
						+ (mCurrentStickyView.getHeight() + mStickyViewTopOffset);

				invalidate(left, top, right, bottom);
			}
			postDelayed(this, 16);
		}
	};

	public StickyScrollView(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public StickyScrollView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		mShadowDrawable = context.getResources().getDrawable(
				R.drawable.sticky_shadow_default);
		mStickyViews = new LinkedList<View>();
		density = context.getResources().getDisplayMetrics().density;
	}

	/**
	 * 找到設置tag的View
	 * 
	 * @param viewGroup
	 */
	private void findViewByStickyTag(ViewGroup viewGroup) {
		int childCount = ((ViewGroup) viewGroup).getChildCount();
		for (int i = 0; i < childCount; i++) {
			View child = viewGroup.getChildAt(i);

			if (getStringTagForView(child).contains(STICKY)) {
				mStickyViews.add(child);
			}

			if (child instanceof ViewGroup) {
				findViewByStickyTag((ViewGroup) child);
			}
		}

	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
		super.onLayout(changed, l, t, r, b);
		if (changed) {
			findViewByStickyTag((ViewGroup) getChildAt(0));
		}
		showStickyView();
	}

	@Override
	protected void onScrollChanged(int l, int t, int oldl, int oldt) {
		super.onScrollChanged(l, t, oldl, oldt);
		showStickyView();
	}

	/**
	 * 
	 */
	private void showStickyView() {
		View curStickyView = null;
		View nextStickyView = null;

		for (View v : mStickyViews) {
			int topOffset = v.getTop() - getScrollY();

			if (topOffset <= 0) {
				if (curStickyView == null
						|| topOffset > curStickyView.getTop() - getScrollY()) {
					curStickyView = v;
				}
			} else {
				if (nextStickyView == null
						|| topOffset < nextStickyView.getTop() - getScrollY()) {
					nextStickyView = v;
				}
			}
		}

		if (curStickyView != null) {
			mStickyViewTopOffset = nextStickyView == null ? 0 : Math.min(
					0,
					nextStickyView.getTop() - getScrollY()
							- curStickyView.getHeight());
			mCurrentStickyView = curStickyView;
			post(mInvalidataRunnable);
		} else {
			mCurrentStickyView = null;
			removeCallbacks(mInvalidataRunnable);

		}

	}

	private String getStringTagForView(View v) {
		Object tag = v.getTag();
		return String.valueOf(tag);
	}

	/**
	 * 將sticky畫出來
	 */
	@Override
	protected void dispatchDraw(Canvas canvas) {
		super.dispatchDraw(canvas);
		if (mCurrentStickyView != null) {
			// 先保存起來
			canvas.save();
			// 將座標原點移動到(0, getScrollY() + mStickyViewTopOffset)
			int left = DataUtil.dp2Px(getContext(), 10);
			canvas.translate(left, getScrollY() + mStickyViewTopOffset);

			if (mShadowDrawable != null) {
				int top = mCurrentStickyView.getHeight() + mStickyViewTopOffset;
				int right = mCurrentStickyView.getWidth();
				int bottom = top + (int) (density * defaultShadowHeight + 0.5f);
				mShadowDrawable.setBounds(0, top, right, bottom);
				mShadowDrawable.draw(canvas);
			}

			canvas.clipRect(0, mStickyViewTopOffset,
					mCurrentStickyView.getWidth(),
					mCurrentStickyView.getHeight());

			mCurrentStickyView.draw(canvas);

			// 重置座標原點參數
			canvas.restore();
		}
	}

	@Override
	public boolean dispatchTouchEvent(MotionEvent ev) {
		if (ev.getAction() == MotionEvent.ACTION_DOWN) {
			redirectTouchToStickyView = true;
		}

		if (redirectTouchToStickyView) {
			redirectTouchToStickyView = mCurrentStickyView != null;

			if (redirectTouchToStickyView) {
				redirectTouchToStickyView = ev.getY() <= (mCurrentStickyView
						.getHeight() + mStickyViewTopOffset)
						&& ev.getX() >= mCurrentStickyView.getLeft()
						&& ev.getX() <= mCurrentStickyView.getRight();
			}
		}

		if (redirectTouchToStickyView) {
			ev.offsetLocation(
					0,
					-1
							* ((getScrollY() + mStickyViewTopOffset) - mCurrentStickyView
									.getTop()));
		}
		return super.dispatchTouchEvent(ev);
	}

	private boolean hasNotDoneActionDown = true;

	@Override
	public boolean onTouchEvent(MotionEvent ev) {
		if (redirectTouchToStickyView) {
			ev.offsetLocation(0,
					((getScrollY() + mStickyViewTopOffset) - mCurrentStickyView
							.getTop()));
		}

		if (ev.getAction() == MotionEvent.ACTION_DOWN) {
			hasNotDoneActionDown = false;
		}

		if (hasNotDoneActionDown) {
			MotionEvent down = MotionEvent.obtain(ev);
			down.setAction(MotionEvent.ACTION_DOWN);
			super.onTouchEvent(down);
			hasNotDoneActionDown = false;
		}

		if (ev.getAction() == MotionEvent.ACTION_UP
				|| ev.getAction() == MotionEvent.ACTION_CANCEL) {
			hasNotDoneActionDown = true;
		}
		return super.onTouchEvent(ev);
	}
}

2 在xml文件中，需要此效果的srollview中引用此自定義scrollview,並在需要固定的view中，添加屬性： android:tag="sticky"

例如：

 <com.blueware.rpm.widget.StickyScrollView
        android:id="@+id/SV_Pandect"
        style="@style/layout_vertical"
        android:layout_weight="3"
        android:scrollbars="vertical" >
...........
 <Button
                android:id="@+id/B_browser"
                android:layout_width="match_parent"
                android:layout_height="@dimen/stitle_hight"
                android:layout_weight="1"
                android:background="#F8F8F8"
                android:padding="3dp"
                android:text="瀏覽器"
               <span style="background-color: rgb(153, 153, 255);"> android:tag="sticky"</span>
                android:textSize="@dimen/stitle_size" />

.....................
 </com.blueware.rpm.widget.StickyScrollView>