<?xml version="1.0" encoding="utf-8"?>
<Window size="300,200" caption="0,0,300,20">
<HorizontalLayout name="aaaa" bkcolor="#FFEEEEEE" >
<VerticalLayout name="xxxxxx" float="true" pos="50,20,250,195" hscrollbar="true" vscrollbar="true" sepheight="4" >
<Label name="child1" text="text1" float="false" pos="0,0,300,200" bordercolor="#FFEE00EE" bkcolor="#FF0000EE" textcolor="#FF010101"/>
<Label name="child2" text="text2" float="false" pos="0,0,200,200" bordercolor="#FFEE00EE" bkcolor="#FF0000EE" textcolor="#FF01FF01"/>
</VerticalLayout>
</HorizontalLayout>
</Window>
這是一個窗口,它包含一個豎的佈局,顯示出來初始狀態是這樣的:
在佈局中,2個子控件所需要的長和寬,比佈局本身的大小要大,所以需要2個滾動條來拉動顯示。
我們可以看到橫豎兩個滾動條。
不過,我們拉動滾動條,卻不能完全展示子控件。如下圖:
雖然橫向滾動條拉到了最右邊,但Label控件child1的右邊沒有展示出來。
檢查代碼,發現CVerticalLayoutUI的SetPos方法如下:
void CVerticalLayoutUI::SetPos(RECT rc)
{
...省略若干代碼
// Process the scrollbar
ProcessScrollBar(rc, 0, cyNeeded);
}
在最後面,調用了基類CContainerUI的ProcessScrollBar方法,來設置滾動條信息,ProcessScrollBar函數的第二個參數是設置橫向滾動條信息,第三個參數是豎向滾動條。此時設置橫向的參數爲0,豎向的是cyNeeded。顯然,這裏忽略了橫向的,所以在豎向佈局VerticalLayout中,橫向滾動條不能正常顯示。
在CVerticalLayoutUI::SetPos中,所有涉及到cyNeeded的代碼如下:
int cyNeeded = 0;
int cyExpand = 0;
if( nAdjustables > 0 ) cyExpand = MAX(0, (szAvailable.cy - cyFixed) / nAdjustables);
// Position the elements
SIZE szRemaining = szAvailable;
int iPosY = rc.top;
if( m_pVerticalScrollBar && m_pVerticalScrollBar->IsVisible() ) {
iPosY -= m_pVerticalScrollBar->GetScrollPos();
}
int iPosX = rc.left;
if( m_pHorizontalScrollBar && m_pHorizontalScrollBar->IsVisible() ) {
iPosX -= m_pHorizontalScrollBar->GetScrollPos();
}
int iAdjustable = 0;
int cyFixedRemaining = cyFixed;
for( int it2 = 0; it2 < m_items.GetSize(); it2++ ) {
CControlUI* pControl = static_cast<CControlUI*>(m_items[it2]);
if( !pControl->IsVisible() ) continue;
if( pControl->IsFloat() ) {
SetFloatPos(it2);
continue;
}
RECT rcPadding = pControl->GetPadding();
szRemaining.cy -= rcPadding.top;
SIZE sz = pControl->EstimateSize(szRemaining);
if( sz.cy == 0 ) {
iAdjustable++;
sz.cy = cyExpand;
// Distribute remaining to last element (usually round-off left-overs)
if( iAdjustable == nAdjustables ) {
sz.cy = MAX(0, szRemaining.cy - rcPadding.bottom - cyFixedRemaining);
}
if( sz.cy < pControl->GetMinHeight() ) sz.cy = pControl->GetMinHeight();
if( sz.cy > pControl->GetMaxHeight() ) sz.cy = pControl->GetMaxHeight();
}
else {
if( sz.cy < pControl->GetMinHeight() ) sz.cy = pControl->GetMinHeight();
if( sz.cy > pControl->GetMaxHeight() ) sz.cy = pControl->GetMaxHeight();
cyFixedRemaining -= sz.cy;
}
sz.cx = pControl->GetFixedWidth();
if( sz.cx == 0 ) sz.cx = szAvailable.cx - rcPadding.left - rcPadding.right;
if( sz.cx < 0 ) sz.cx = 0;
if( sz.cx < pControl->GetMinWidth() ) sz.cx = pControl->GetMinWidth();
if( sz.cx > pControl->GetMaxWidth() ) sz.cx = pControl->GetMaxWidth();
RECT rcCtrl = { iPosX + rcPadding.left, iPosY + rcPadding.top, iPosX + rcPadding.left + sz.cx, iPosY + sz.cy + rcPadding.top + rcPadding.bottom };
pControl->SetPos(rcCtrl);
iPosY += sz.cy + m_iChildPadding + rcPadding.top + rcPadding.bottom;
cyNeeded += sz.cy + rcPadding.top + rcPadding.bottom;
szRemaining.cy -= sz.cy + m_iChildPadding + rcPadding.bottom;
}
cyNeeded += (nEstimateNum - 1) * m_iChildPadding;
在for循環裏,會統計所有非float子控件的高度
在 cyNeeded += sz.cy + rcPadding.top + rcPadding.bottom; 裏,sz.cy是1個子控件的高度,而rcPadding = pControl->GetPadding(); 是控件的padding屬性,也就是外邊距。
最後yNeeded += (nEstimateNum - 1) * m_iChildPadding; m_iChildPadding是佈局的childpadding屬性,也就是子控件之間的額外距離。
我們可以仿照cyNeeded的計算方式,來算出cxNeeded。因爲是豎向佈局,所以 cyNeeded += sz.cy 這裏是累加,但是橫向值,應該取最寬的控件的值,
所以for循環中的代碼應該是這樣:
int tmp = sz.cx + rcPadding.left + rcPadding.right;
cxNeeded = (tmp > cxNeeded) ? tmp: cxNeeded;
最後cxNeeded += (nEstimateNum - 1) * m_iChildPadding;
此時通過對代碼的瞭解,可以得知:佈局在計算容量面積時,只計算非float類型的子控件,忽略了float類型的子控件。
算出了佈局的寬度後,就應用起來
修改原來的代碼爲:ProcessScrollBar(rc, cxNeeded, cyNeeded);
改完後,發現問題依然。於是,檢查了下ProcessScrollBar的代碼,如下
void CContainerUI::ProcessScrollBar(RECT rc, int cxRequired, int cyRequired)
{
if( m_pHorizontalScrollBar != NULL && m_pHorizontalScrollBar->IsVisible() ) {
RECT rcScrollBarPos = { rc.left, rc.bottom, rc.right, rc.bottom + m_pHorizontalScrollBar->GetFixedHeight()};
m_pHorizontalScrollBar->SetPos(rcScrollBarPos);
}
if( m_pVerticalScrollBar == NULL ) return;
if( cyRequired > rc.bottom - rc.top && !m_pVerticalScrollBar->IsVisible() ) {
m_pVerticalScrollBar->SetVisible(true);
m_pVerticalScrollBar->SetScrollRange(cyRequired - (rc.bottom - rc.top));
m_pVerticalScrollBar->SetScrollPos(0);
m_bScrollProcess = true;
SetPos(m_rcItem);
m_bScrollProcess = false;
return;
}
// No scrollbar required
if( !m_pVerticalScrollBar->IsVisible() ) return;
// Scroll not needed anymore?
int cyScroll = cyRequired - (rc.bottom - rc.top);
if( cyScroll <= 0 && !m_bScrollProcess) {
m_pVerticalScrollBar->SetVisible(false);
m_pVerticalScrollBar->SetScrollPos(0);
m_pVerticalScrollBar->SetScrollRange(0);
SetPos(m_rcItem);
}
else
{
RECT rcScrollBarPos = { rc.right, rc.top, rc.right + m_pVerticalScrollBar->GetFixedWidth(), rc.bottom };
m_pVerticalScrollBar->SetPos(rcScrollBarPos);
if( m_pVerticalScrollBar->GetScrollRange() != cyScroll ) {
int iScrollPos = m_pVerticalScrollBar->GetScrollPos();
m_pVerticalScrollBar->SetScrollRange(::abs(cyScroll));
if( m_pVerticalScrollBar->GetScrollRange() == 0 ) {
m_pVerticalScrollBar->SetVisible(false);
m_pVerticalScrollBar->SetScrollPos(0);
}
if( iScrollPos > m_pVerticalScrollBar->GetScrollPos() ) {
SetPos(m_rcItem);
}
}
}
}
很明顯,cxRequired根本沒有用到。
對於橫向滾動條,只使用了這3行代碼:
if( m_pHorizontalScrollBar != NULL && m_pHorizontalScrollBar->IsVisible() ) {
RECT rcScrollBarPos = { rc.left, rc.bottom, rc.right, rc.bottom + m_pHorizontalScrollBar->GetFixedHeight()};
m_pHorizontalScrollBar->SetPos(rcScrollBarPos);
}
於是,我們需要仿照設置豎向滾動條的方式,來設置橫向滾動條:
void CContainerUI::ProcessScrollBar(RECT rc, int cxRequired, int cyRequired)
{
while(m_pHorizontalScrollBar)
{
if (cxRequired > rc.right - rc.left && !m_pHorizontalScrollBar->IsVisible())
{
m_pHorizontalScrollBar->SetVisible(true);
m_pHorizontalScrollBar->SetScrollRange(cxRequired - (rc.right - rc.left));
m_pHorizontalScrollBar->SetScrollPos(0);
m_bScrollProcess = true;
SetPos(m_rcItem);
m_bScrollProcess = false;
break;
}
if( !m_pHorizontalScrollBar->IsVisible() ) break;
int cxScroll = cxRequired - (rc.right - rc.left);
if (cxScroll <= 0 && !m_bScrollProcess)
{
m_pHorizontalScrollBar->SetVisible(false);
m_pHorizontalScrollBar->SetScrollPos(0);
m_pHorizontalScrollBar->SetScrollRange(0);
SetPos(m_rcItem);
}
else
{
RECT rcScrollBarPos = { rc.left, rc.bottom, rc.right, rc.bottom + m_pHorizontalScrollBar->GetFixedHeight() };
m_pHorizontalScrollBar->SetPos(rcScrollBarPos);
if( m_pHorizontalScrollBar->GetScrollRange() != cxScroll ) {
int iScrollPos = m_pHorizontalScrollBar->GetScrollPos();
m_pHorizontalScrollBar->SetScrollRange(::abs(cxScroll));
if( m_pHorizontalScrollBar->GetScrollRange() == 0 ) {
m_pHorizontalScrollBar->SetVisible(false);
m_pHorizontalScrollBar->SetScrollPos(0);
}
if( iScrollPos > m_pHorizontalScrollBar->GetScrollPos() ) {
SetPos(m_rcItem);
}
}
}
break;
}
while(m_pVerticalScrollBar)
{
if( cyRequired > rc.bottom - rc.top && !m_pVerticalScrollBar->IsVisible() ) {
m_pVerticalScrollBar->SetVisible(true);
m_pVerticalScrollBar->SetScrollRange(cyRequired - (rc.bottom - rc.top));
m_pVerticalScrollBar->SetScrollPos(0);
m_bScrollProcess = true;
SetPos(m_rcItem);
m_bScrollProcess = false;
break;
}
// No scrollbar required
if( !m_pVerticalScrollBar->IsVisible() ) break;
// Scroll not needed anymore?
int cyScroll = cyRequired - (rc.bottom - rc.top);
if( cyScroll <= 0 && !m_bScrollProcess) {
m_pVerticalScrollBar->SetVisible(false);
m_pVerticalScrollBar->SetScrollPos(0);
m_pVerticalScrollBar->SetScrollRange(0);
SetPos(m_rcItem);
}
else
{
RECT rcScrollBarPos = { rc.right, rc.top, rc.right + m_pVerticalScrollBar->GetFixedWidth(), rc.bottom };
m_pVerticalScrollBar->SetPos(rcScrollBarPos);
if( m_pVerticalScrollBar->GetScrollRange() != cyScroll ) {
int iScrollPos = m_pVerticalScrollBar->GetScrollPos();
m_pVerticalScrollBar->SetScrollRange(::abs(cyScroll));
if( m_pVerticalScrollBar->GetScrollRange() == 0 ) {
m_pVerticalScrollBar->SetVisible(false);
m_pVerticalScrollBar->SetScrollPos(0);
}
if( iScrollPos > m_pVerticalScrollBar->GetScrollPos() ) {
SetPos(m_rcItem);
}
}
}
break;
}
}
看看效果
可以看到控件child1的右邊框。
HorizontalLayout也有同樣的問題,可類似修改。