android - 如何隐藏TextView并且只在滚动时显示

Question

我有一个 ScrollView 和 GridView，我想在 GridView 上面放一个 TextView，但在用户滚动到它之前不能看到它。我考虑过负边距，但找不到如何在负边距时使用滚动来获取此 View 的解决方案。

所以基本上:唯一看到的应该是 gridView，但是当用户在 gridView 之上并向上拉时，他应该看到一个 TextView。

编辑:重点是我想从中进行下拉刷新。我不想使用流行的 Internet 库，因为它不能按我想要的方式工作。

编辑 2:

我得到了答案，但这并不完全是我想要实现的。我想平滑地显示隐藏的 TextView(就像在下拉刷新解决方案中一样)并且 setVisibility 使其快速且没有任何平滑度。这是我的代码:

XML:

<com.tas.android.quick.ui.controls.LockableScrollView
        android:id="@+id/scrollView"
        android:fillViewport="true"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

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

            <TextView 
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/pullText"
                android:text="some text" />

            <com.tas.android.quick.ui.controls.ExpandableGridView
                android:id="@+id/gridview"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:clipToPadding="false"
                android:drawSelectorOnTop="true"
                android:fadingEdge="none"
                android:gravity="top"
                android:horizontalSpacing="@dimen/image_grid_hspacing"
                android:listSelector="@drawable/selector_shadow"
                android:numColumns="@integer/grid_num_cols"
                android:paddingBottom="50dp"
                android:scrollbarAlwaysDrawVerticalTrack="false"
                android:scrollbars="none"
                android:scrollingCache="true"
                android:smoothScrollbar="false"
                android:stretchMode="columnWidth"
                android:verticalSpacing="@dimen/image_grid_vspacing"
                android:visibility="visible" />
        </LinearLayout>
    </com.tas.android.quick.ui.controls.LockableScrollView>

和代码:

textview = (TextView) findViewById(R.id.pullText);
        textview.setVisibility(View.VISIBLE);

        scrollView = (LockableScrollView) findViewById(R.id.scrollView);

        scrollView.setScrollingEnabled(false);

...

gridView.setOnScrollListener(new OnScrollListener() {
                        @Override
                        public void onScrollStateChanged(AbsListView view, int scrollState) {
                            switch(scrollState) {
                            case 2: // SCROLL_STATE_FLING 
                                //hide button here
                                textview.setVisibility(View.VISIBLE);
                                break;

                            case 1: // SCROLL_STATE_TOUCH_SCROLL 
                                //hide button here
                                textview.setVisibility(View.GONE);
                                break;

                            case 0: // SCROLL_STATE_IDLE 
                                //show button here
                                textview.setVisibility(View.GONE);
                                break;
                            }
                        }

                        @Override
                        public void onScroll(AbsListView view, int firstVisibleItem,
                                int visibleItemCount, int totalItemCount) {
                                }
                            }
                        }
                    });

Answer 1

您可以通过对 GridView 使用 setOnScrollListener 来完成此操作:

gridview.setOnScrollListener(new OnScrollListener() {

   @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
              int visibleItemCount, int totalItemCount) {

  }

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
        // TODO Auto-generated method stub
  switch(scrollState) {
    case 2: // SCROLL_STATE_FLING 
    //hide button here
    yourTextView.setVisibility(View.GONE);
    break;

    case 1: // SCROLL_STATE_TOUCH_SCROLL 
    //hide button here
    yourTextView.setVisibility(View.GONE);
    break;

    case 0: // SCROLL_STATE_IDLE 
    //show button here
    yourTextView.setVisibility(View.VISIBLE);
    break;

        default:
     //show button here
    btn.setVisibility(View.VISIBLE);
    break;
       }
    }
 });

编辑 1

为了平滑度，试试这个(未测试)

 switch(scrollState) {
case 2: // SCROLL_STATE_FLING 

Animation animation = new TranslateAnimation(0,0,0,1000);
animation.setDuration(1000);
mytextview.startAnimation(animation);
mytextview.setVisibility(View.GONE);

break;

case 1: // SCROLL_STATE_TOUCH_SCROLL 
//hide button here
Animation animation = new TranslateAnimation(0,0,0,1000);
animation.setDuration(1000);
mytextview.startAnimation(animation);
yourTextView.setVisibility(View.GONE);
break;

case 0: // SCROLL_STATE_IDLE 
//show button here
Animation animation = new TranslateAnimation(0,0,0,1000);
animation.setDuration(1000);
mytextview.startAnimation(animation);
yourTextView.setVisibility(View.VISIBLE);
break;

    default:
 //show button here
Animation animation = new TranslateAnimation(0,0,0,1000);
animation.setDuration(1000);
mytextview.startAnimation(animation);
yourTextView.setVisibility(View.VISIBLE);
break;