| NONSHARABLE_CLASS | ( | TulTextResourceUtils | ) |
Utility that provides methods to load and format resource strings. String Loader API provides an interface to load and format resource strings that may contain parameter(s) (%U for (unicode) text or or %N for numerical). Resource strings are usually defined in an RSS file.
The API consists of the TulTextResourceUtils class. All methods are static, so there is no need to explicitly allocate memory for the interface class. The implementation needs a CCoeEnv instance to access for example the resource files.
Usage:
Applications load and format resource strings from normal resources with static methods of the TulTextResourceUtils class. The loading is done with the LoadL and LoadLC methods and with the Load method in situations where memory allocation from the heap is not possible. Formatting is done automatically after loading in the LoadL and LoadLC methods, but it can also be done separately with the Format method in situations where memory allocation from the heap is not possible. For reading the resource strings with the Load, LoadL and LoadLC methods, the user should provide a pointer to CCoeEnv for efficiency reasons. If the pointer is not provided, the implementation uses the CCoeEnv::Static method internally to get it.
Different size displays can handle different length strings. To take full advantage of this fact, TulTextResourceUtils supports resource strings with multiple options for strings, separated by the character 0x0001. Each such string can contain the same or different sub string keys (%U and %N). TulTextResourceUtils returns all strings, it is the responsibility of the caller to parse the result and choose the proper string to display.
Setting the maximum sub string length may be done in the text resources. Sub string maximum lengths can be localized separately for every language. The maximum sub string length is of the format: %U[NN] where NN is a number [01..99]. Please note that NN must always consist of two characters, i.e. if the sub string maximum length is eight characters, the value to be used is 08, not plain 8. If the number of characters exceeds the maximum length, the sub string is cut to fit and the last character is replaced with an ellipsis character.
The following examples describe the usage of the String Loader API.
Usage when one TInt is added:
// In .loc -file
// #define text_example "You have %N undone tasks."
// In .rss -file
// RESOURCE TBUF r_text_example { buf = text_example; }
// (In the .cpp -file)
#include <coeutils.h>
// Get CCoeEnv instance
CEikonEnv* iEikonEnv = CEikonEnv::Static();
TInt number(324);
// Method reads a resource string with memory allocation
// and replaces the first %N-string in it with replacement TInt.
// The heap descriptor must be destroyed when it is no longer needed.
// iEikonEnv is needed for loading the resource string.
HBufC* stringholder = TulTextResourceUtils::LoadL(R_TEXT_EXAMPLE, number, iEikonEnv);
// The 'number' is added to the resource string. The result is
// that stringholder points to a heap descriptor containing string:
// "You have 324 undone tasks."
// Delete the heap descriptor
delete stringholder;
Usage when several strings are added:
An index can be included to parameters. Several parameters can have same index if the same replacement is needed multiple times.
// In .loc -file
// #define text_example "I'm %2U%1U %3U%0U fine."
// In .rss -file
// RESOURCE TBUF r_text_example { buf = text_example; }
// In the .cpp -file
#include <coeutils.h>
// Get CCoeEnv instance
CEikonEnv* iEikonEnv = CEikonEnv::Static();
CDesCArrayFlat* strings = new CDesCArrayFlat(4);
CleanupStack::PushL(strings);
strings->AppendL(_L("orking")); //First string
strings->AppendL(_L("ll")); //Second string
strings->AppendL(_L("sti")); //Third string
strings->AppendL(_L("w")); //Fourth string
// Method reads a resource string with memory allocation and replaces
// the %(index)U strings in it with replacement strings from an array.
// The heap descriptor must be destroyed when it is no longer needed.
// iEikonEnv is needed for loading the resource string.
HBufC* stringholder = TulTextResourceUtils::LoadL(R_TEXT_EXAMPLE, *strings, iEikonEnv);
// Four strings are added to the resource string. The result is
// that stringholder points to a heap descriptor containing string:
// "I'm still working fine."
// Pop and delete strings array
CleanupStack::PopAndDestroy();
// Delete the heap descriptor
delete stringholder;
Usage with scalable UI support:
// In .loc -file
// #define TEXT_EXAMPLE "You have missed %N messages from %U."<0x0001>"Missed %N msgs from %U."<0x0001>"Missed %N msgs."
// In .rss -file
// RESOURCE TBUF R_TEXT_EXAMPLE { buf = TEXT_EXAMPLE; }
// In the .cpp -file
#include <coeutils.h>
// Get CCoeEnv instance
CEikonEnv* iEikonEnv = CEikonEnv::Static();
TInt number(12);
_LIT(name, "John Doe");
// Method reads a resource string with memory allocation,
// replaces all %N strings in it with a replacement TInt and
// all %U strings in it with a replacement string.
// The heap descriptor must be destroyed when it is no longer needed.
// iEikonEnv is needed for loading the resource string.
HBufC stringholder = TulTextResourceUtils::LoadL(R_TEXT_EXAMPLE, name, number, iEikonEnv);
// The number and name are added to the resource string. The result is
// that stringholder points to a heap descriptor containing string:
// "You have missed 12 messages from John Doe.\001Missed 12 msgs from John
// Doe.\001Missed 12 msgs."
// Delete the heap descriptor
delete stringholder;
Error handling:
The leave mechanism of the Symbian OS environment is used to handle memory exhaustion. The panic mechanism is used to handle programming errors while debugging. TulTextResourceUtils panics for seven different reasons. The panic category is named TulTextResourceUtils. The panic codes are:
ETooFewArguments = 0 (Unsolved parameters in resource string.)
ETooManyArguments = 1 (Already solved all parameters in resource string.)
EKeyStringNotFound = 2 (The key string wasn't found in formatting.)
EInvalidIndex = 3 (Invalid index in Format-method)
EDescriptorTooSmall = 4 (Too small destination descriptor.)
ECCoeEnvNotInitialized = 5 (CCoeEnv is not initialized)
EInvalidSubstitute = 6 (Substituted string contains KSubStringSeparator)