如何从滚动视图中删除子视图?-尊龙凯时

问题描述

如何从我的滚动视图中删除所有子视图...

how do i remove all subviews from my scrollview...

我在滚动视图中有一个 uiview 和它上方的按钮，如下所示....

i have a uiview and a button above it in the scrollview something like this....

这是我在滚动视图中添加子视图的代码

here is my code to add subview in scroll view

-(void)addonebutton:(nsinteger)mybuttontag {
lastbuttonnumber = lastbuttonnumber   1;
if ((lastbuttonnumber == 1) || ((lastbuttonnumber%2) == 1)) {
btnleft = 8;}
else if ((lastbuttonnumber == 2) || ((lastbuttonnumber%2) == 0)) {
btnleft = 162;
}
cgrect frame1 = cgrectmake(btnleft, btntop, 150, 150);
cgrect frame2 = cgrectmake(btnleft, btntop, 150, 150);
uibutton *button = [uibutton buttonwithtype:uibuttontypecustom];
button.frame = frame1;
button.tag = mybuttontag;
[button addtarget:self action:@selector(buttonclick:) forcontrolevents:uicontroleventtouchupinside];
[button setbackgroundcolor:[uicolor clearcolor]];
[button setbackgroundimage:[uiimage imagenamed:@"waitscreen.png"] forstate:uicontrolstatehighlighted];
    graphthumbviewcontrollerobj = [[graphthumbviewcontroller alloc] initwithpagenumber:[[graphidarray objectatindex:mybuttontag]intvalue]];
    graphthumbviewcontrollerobj.view.frame=frame2;
    graphthumbviewcontrollerobj.lblcounter.text=[nsstring stringwithformat:@"%d of %d",mybuttontag 1,flashcardsid.count];
    graphthumbviewcontrollerobj.lblquestion.text=[flashcardtext objectatindex:mybuttontag];
    [myscrollview addsubview:graphthumbviewcontrollerobj.view];
[myscrollview addsubview:button];
if ((lastbuttonnumber == 2) || ((lastbuttonnumber%2) == 0)) {
btntop = btntop   162;
}
if (btntop 150 > myscrollview.frame.size.height) {
myscrollview.contentsize = cgsizemake((myscrollview.frame.size.width), (btntop 160));}
}

这是删除子视图的代码

if(myscrollview!=nil)
{
        while ([myscrollview.subviews count] > 0) {
            //nslog(@"subviews count=%d",[[myscrollview subviews]count]);
            [[[myscrollview subviews] objectatindex:0] removefromsuperview];
}

推荐答案

要从任何视图中删除所有子视图，您可以遍历子视图并为每个子视图发送 removefromsuperview 调用:

to remove all the subviews from any view, you can iterate over the subviews and send each a removefromsuperview call:

// with some valid uiview *view:
for(uiview *subview in [view subviews]) {
    [subview removefromsuperview];
}

不过，这完全是无条件的，并且会删除给定视图中的所有子视图.如果你想要更细粒度的东西，你可以采取几种不同的方法:

this is entirely unconditional, though, and will get rid of all subviews in the given view. if you want something more fine-grained, you could take any of several different approaches:

• 维护您自己的不同类型的视图数组，以便稍后以相同的方式向它们发送 removefromsuperview 消息
• 保留您创建它们的所有视图并保留指向这些视图的指针，以便您可以根据需要单独发送它们 removefromsuperview
• 在上述循环中添加 if 语句，检查类是否相等.例如，要仅删除视图中存在的所有 uibutton(或 uibutton 的自定义子类)，您可以使用以下内容:

• maintain your own arrays of views of different types so you can send them removefromsuperview messages later in the same manner
• retain all your views where you create them and hold on to pointers to those views, so you can send them removefromsuperview individually as necessary
• add an if statement to the above loop, checking for class equality. for example, to only remove all the uibuttons (or custom subclasses of uibutton) that exist in a view, you could use something like:

// again, valid uiview *view:
for(uiview *subview in [view subviews]) {
    if([subview iskindofclass:[uibutton class]]) {
        [subview removefromsuperview];
    } else {
        // do nothing - not a uibutton or subclass instance
    }
}