Dart StringBuffer by Examples

In this Dart tutorial, we learn how to use StringBuffer class, a class for concatenating strings efficiently in Dart programming language.

How to use StringBuffer class to build a String

In the following example Dart program we use StringBuffer to build a String by using write() method to add String content and then use toString() method to get the final String.

void main() {
  StringBuffer stringBuffer = new StringBuffer();
  stringBuffer.write("Hello, ");
  stringBuffer.write("Mobile");
  stringBuffer.write("Code");
  stringBuffer.write(".Dev");

  print(stringBuffer.toString());
}

The output is:

Hello, MobileCode.Dev

The writeln() method to write a line of String value.

void main() {
  StringBuffer stringBuffer = new StringBuffer();
  stringBuffer.writeln("Hello, ");
  stringBuffer.writeln("Mobile");
  stringBuffer.writeln("Code");
  stringBuffer.writeln(".Dev");

  print(stringBuffer.toString());
}

The output is:

Hello,
Mobile
Code
.Dev

The clear() method to clear StringBuffer content.

void main() {
  StringBuffer stringBuffer = new StringBuffer();
  stringBuffer.write("First ");
  stringBuffer.write("String");
  
  print(stringBuffer.toString());
  stringBuffer.clear();

  stringBuffer.write("Second ");
  stringBuffer.write("String");
  
  print(stringBuffer.toString());
  stringBuffer.clear();

  stringBuffer.write("Third ");
  stringBuffer.write("String");
  
  print(stringBuffer.toString());
}

The output is:

First String
Second String
Third String

Check a StringBuffer is empty or not

Using isEmpty property.

void main() {
  StringBuffer stringBuffer = new StringBuffer();
  
  if(stringBuffer.isEmpty) {
    print("StringBuffer is empty");
  } else {
    print("StringBuffer is not empty");
  }
}

The output is:

StringBuffer is empty

void main() {
  StringBuffer stringBuffer = new StringBuffer("mobilecode.dev");
  
  if(stringBuffer.isEmpty) {
    print("StringBuffer is empty");
  } else {
    print("StringBuffer is not empty");
  }
}

The output is:

StringBuffer is not empty

Using isNotEmpty property.

void main() {
  StringBuffer stringBuffer = new StringBuffer();
  
  if(stringBuffer.isNotEmpty) {
    print("StringBuffer is not empty");
  } else {
    print("StringBuffer is empty");
  }
}

The output is:

StringBuffer is empty

void main() {
  StringBuffer stringBuffer = new StringBuffer("mobilecode.dev");
  
  if(stringBuffer.isNotEmpty) {
    print("StringBuffer is not empty");
  } else {
    print("StringBuffer is empty");
  }
}

The output is:

StringBuffer is not empty

Happy Coding 😊

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