B4A Library Unlocking the Full Potential: A Custom StringBuilder for B4A

Introduction​

When it comes to string manipulation, the StringBuilder class becomes a powerful tool in any developer’s arsenal. However, in B4A (Basic4Android), the built-in StringBuilder has its limitations.

The Issue with B4A’s Default StringBuilder​

1. Read-Only Length:
   • B4A’s default StringBuilder lacks a modifiable Length property. This means we can’t easily adjust the string’s size or set it to zero to clear its content.
   • Imagine trying to resize the text or wipe it clean to concatenate new content. Frustrating, right?
2. Missing Methods:
   • Some essential methods are absent from the default StringBuilder. For instance, reversing character order or inserting text at a specific position isn’t straightforward.

The Solution: EnhancedStringBuilder​

Let’s explore its features:

1. Initialization:
   • We ensure that the EnhancedStringBuilder is created only once during the app’s lifetime—no redundant instances!
   • Initialize it with Initialize.
2. Adding Text:
   • Use Append(Texto As String) to add text to your custom EnhancedStringBuilder.
   • Example: Append("The cat").
3. Inserting Text:
   • Insert text at a specific index using Insert(Index As Int, Texto As String).
   • Example: Insert(5, " sleeps.").
4. Deleting Text:
   • Remove characters from the EnhancedStringBuilder with Delete(StartIndex As Int, EndIndex As Int).
   • Example: Delete(2, 6).
5. Reversing:
   • Change character order with Reverse.
   • Perfect for palindromes or secret messages.
6. Getting the Length:
   • Retrieve the current length with GetLength As Int.
   • Goodbye read-only restrictions.
7. SetLength: Adjusting Length
   • The SetLength(Length As Int) method is a hidden gem.
   • Keep only the first N characters by calling SetLength(N).
   • For example, if you have “Hello, world” in your EnhancedStringBuilder and execute SetLength(5), you’ll get “Hello,”.
   • To wipe all content, pass a value of 0 to SetLength.
8. Clear: Quick Cleanup
   • If you want to erase everything from the EnhancedStringBuilder, execute Clear.

Example Code

Sub EnhancedStringBuilderTest
    Dim EnhStrBuilder As EnhancedStringBuilder
    Dim Texto As String
  
    EnhStrBuilder.Initialize
    EnhStrBuilder.Append("The")
    EnhStrBuilder.Append(" ")
    EnhStrBuilder.Append(": ")
    EnhStrBuilder.Append("EnhancedStringBuilder")
  
    Texto = EnhStrBuilder.ToString
  
    Log(Texto)
    Log("Length:" & EnhStrBuilder.GetLength)
  
    EnhStrBuilder.Insert(4, "solution")
    Texto = EnhStrBuilder.ToString
    Log(Texto)
  
    EnhStrBuilder.Reverse
    Texto = EnhStrBuilder.ToString
    Log(Texto)
  
    EnhStrBuilder.Reverse
    Texto = EnhStrBuilder.ToString
    Log(Texto)
  
    EnhStrBuilder.Delete(12, EnhStrBuilder.GetLength)
    Texto = EnhStrBuilder.ToString
    Log(Texto)
  
    EnhStrBuilder.SetLength(3)
    Texto = EnhStrBuilder.ToString
    Log(Texto)
  
    EnhStrBuilder.Clear
    Texto = EnhStrBuilder.ToString
    Log("(" & Texto & ")")
End Sub

Conclusion​

The EnhancedStringBuilder frees developers from the limitations of B4A’s default StringBuilder, saving time and headaches when handling strings. Harness its potential and simplify your code!

I am attaching the EnhancedStringBuilder library along with a sample project for testing. It also demonstrates how to use the function.

If you find this library useful, consider making a donation to my PayPal account paypal.me/Carlos7000

 

[William Lancee]

The Issue with B4A’s Default StringBuilder

1. Read-Only Length:
   • B4A’s default StringBuilder lacks a modifiable Length property. This means we can’t easily adjust the string’s size or set it to zero to clear its content.
   • Imagine trying to resize the text or wipe it clean to concatenate new content. Frustrating, right?
2. Missing Methods:
   • Some essential methods are absent from the default StringBuilder. For instance, reversing character order or inserting text at a specific position isn’t straightforward.

I agree that the built-in StringBuilder has some quirkiness and that this Class could be helpful.
However, for completeness and to avoid misunderstanding by those not familiar with StringBuilder...

1. While sb.Length is read-only, it is easily modifiable by adding or removing a set of characters.
2. sb.Insert is a valid method and works exactly the same as in EnhancedStringBuilder.
3. sb.Remove is a valid method and works the same as .Delete in EnhancedStringBuilder.

It is true that reversing characters in StringBuilder is not built-in, it is very easy to achieve with four lines of code (see code below).
Moreover, in all my programming with B4X, I have not yet needed to reverse characters in a StringBuilder object.

Clearing a StringBuilder object is as easy as initializing it again. I see no limitations.

    Dim sb As StringBuilder
    sb.Initialize
    sb.Append("The cat on the hot tin roof")
    Log(sb)
    'The cat on the hot tin roof
    
    sb.Initialize                                'clear sb
    sb.Append("The quick fox")
    Log(sb)
    'The quick fox

    sb.Remove(sb.Length - 5, sb.Length)            'shorten length by 5
    Log(sb)
    'The quic

    sb.Append("k fox jumped over the ...")        'lengthen by appending text
    Log(sb)
    'The quick fox jumped over the ...
    
    'alternative clearing technique
    sb.Remove(0, sb.Length)
    Log(sb)
    sb.Append("1 2 3 5 6 7")
    
    'insert a substring
    sb.Insert(3, " 4")                            
    Log(sb)
    '1 2 4 3 5 6 7

    'remove a substring
    sb.Remove(3, 3 + 2)                            
    Log(sb)
    '1 2 3 5 6 7
    
    'reverse char order
    Dim sbstr As String = sb.toString
    sb.Initialize
    For i = sbstr.Length - 1 To 0 Step -1
        sb.Append(sbstr.CharAt(i))
    Next
    Log(sb)
    '7 6 5 3 2 1

 

[carlos7000]

Hi William,

I’ve been working with StringBuilder for some time, and while it’s true that the limitations of this class can be mitigated following your suggestions, I believe that reducing the code also improves clarity. When we need to revisit the code later, a more concise approach makes it easier to understand. Additionally, longer code not only complicates comprehension but also increases the likelihood of errors and maintenance challenges.

As you know, time is money, and the faster and simpler we can develop our applications, the better. Although this library I’ve created isn’t a silver bullet, I hope it helps other programmers save time and focus on more critical issues.

Thank you for your understanding and support!

Best regards