Symbian开发笔记(一)

CTest_1AppUi::HandleCommandL(TInt aCommand) { switch ( aCommand ) { case EAknSoftkeyBack: case EEikCmdExit: { _LIT(KQueryDelete,"Are you sure to delete it?"); CAknQueryDialog* dlg = new(ELeave) CAknQueryDialog(const_cast<TDesC&>(KQueryDelete()),CAknQueryDialog::EWarningTone); dlg->ExecuteLD(R_DIALOG_DELETE_QUERY); break; } case ETest_1CmdAppTest: { // Info message shown only in the emulator iEikonEnv->InfoMsg(_L("test")); // Load localized message from the resource file HBufC* message = CEikonEnv::Static()->AllocReadResourceLC(R_MESSAGE_TEXT); // Show information note dialog CAknInformationNote* note = new (ELeave) CAknInformationNote; note->ExecuteLD(message->Des()); CleanupStack::PopAndDestroy(message); break; } // TODO: Add Your command handling code here default: break; } 这里面有几个知识点: 1:_LIT()宏所定义的常量并不是描述符,但可以通过使用一个重载的运算符()将其转换为const TDesC&类型的描述符。 2:CAknQueryDialog的第一个参数需要一个TDesC&类型的参数,所以我们需要把KQueryDelete()强制转换成非const类型的,这需要使用C++中的强制类型转换const_cast<TDesC&>。 3:千万注意要把const_cast<TDesC&>所接的数据加上()。

void CTest_1AppUi::HandleCommandL(TInt aCommand) { switch ( aCommand ) { case EAknSoftkeyBack: case EEikCmdExit: { _LIT(KQueryDelete,"Are you sure to delete it?"); CAknQueryDialog* dlg = new(ELeave) CAknQueryDialog(const_cast<TDesC&>(KQueryDelete()),CAknQueryDialog::EWarningTone); TInt temp = dlg->ExecuteLD(R_DIALOG_DELETE_QUERY); _LIT(KReturnValue,"the return value is :"); HBufC* iBuf = HBufC::NewLC(100); iBuf->Des().Copy(KReturnValue); iBuf->Des().AppendNum(temp); CEikonEnv::Static()->InfoMsg(*iBuf); CleanupStack::PopAndDestroy(iBuf); break; } default: break; } } 从程序执行中我们可以看到,当我们点dlg的NO按钮时,temp的值为一个正数(程序中是3005),而当我们点dlg 的OK的时候,temp的值为0。 所以我们在很多程序中可以看到类似下面的代码: if(dlg->ExecuteLD(R_DIALOG_DELETE_QUERY)) { TInt index = iListBox->CurrentItemIndex(); TName name(db.iName); iUi->iDB->iArrayDB->Delete(index); iUi->iDB->SaveDBL(); CEikonEnv::Static()->ReadResource(info, R_STR_DELETE_TIPS); tips.Format(info, &name); ShowNotify(tips); if(iUi->iDB->iArrayDB->Count()==0) { CEikonEnv::Static()->ReadResource(info, R_STR_NO_CD_TIPS); ShowNotify(info); CreateFunctionListBoxL(); } else { CreateRecordListBoxL(); } } 也就是判断我们是否点击了Dialog的OK按钮。

RESOURCE LOCALISABLE_APP_INFO r_httpenginetest_localisable_app_info
{
short_caption = "HttpEngine";
caption_and_icon =
CAPTION_AND_ICON_INFO
{
caption = "HttpEngineTest";
number_of_icons = 2;
icon_file = "\\resource\\apps\\HttpEngineTestaif.mbm";
};
}

RESOURCE RSS_SIGNATURE {}

RESOURCE TBUF { buf=""; }

RESOURCE EIK_APP_INFO
{
menubar = r_httpenginetest_menubar;
cba = R_AVKON_SOFTKEYS_OPTIONS_BACK;
}

这样写会报告“系统错误”并看不到应用程序的icon，看来签名、文档名缓冲还是要放前面，如下：

RESOURCE RSS_SIGNATURE {}

RESOURCE TBUF { buf=""; }

RESOURCE LOCALISABLE_APP_INFO r_httpenginetest_localisable_app_info
{
short_caption = "HttpEngine";
caption_and_icon =
CAPTION_AND_ICON_INFO
{
caption = "HttpEngineTest";
number_of_icons = 2;
icon_file = "\\resource\\apps\\HttpEngineTestaif.mbm";
};
}

RESOURCE EIK_APP_INFO
{
menubar = r_httpenginetest_menubar;
cba = R_AVKON_SOFTKEYS_OPTIONS_BACK;
}

其实上面这样改，在程序运行到BaseConstructL(EAknEnableSkin)时会报告“User 23”系统错误，原因是我们把LOCALISABLE_APP_INFO放到了EIK_APP_INFO前面去了，应该像下面这样改：

NAME MHWA

#include <eikon.rh>
#include <avkon.rsg>
#include <avkon.rh>
#include <avkon.mbg>
#include <appinfo.rh>

RESOURCE RSS_SIGNATURE {}

RESOURCE TBUF r_default_document_name
{
buf="";
}

RESOURCE EIK_APP_INFO
{
menubar = r_httpenginetest_menubar;
cba = R_AVKON_SOFTKEYS_OPTIONS_BACK;
}

RESOURCE LOCALISABLE_APP_INFO r_httpenginetest_localisable_app_info
{
short_caption = "HttpEngine";
caption_and_icon =
CAPTION_AND_ICON_INFO
{
caption = "HttpEngineTest";
number_of_icons = 2;
icon_file = "\\resource\\apps\\HttpEngineTestaif.mbm";
};
}