5.11. Introduction to Object Oriented Programming in Dart: Exception Handling

Object-oriented programming (OOP) is a programming paradigm that uses objects and their interactions to design applications and software programs. Dart, the programming language used in Flutter, also supports OOP. This article will introduce the concept of exception handling in object-oriented programming in Dart.

In programming, an exception is an abnormal event that occurs during program execution and interrupts the normal flow of the program. Exception handling is a mechanism for handling errors and exceptions in a controlled manner.

In Dart, exception handling is done using try, catch, and finally blocks. The 'try' block is used to wrap code that could potentially throw an exception. The 'catch' block is used to catch and handle the exception if one occurs. The 'finally' block is used to execute code regardless of whether an exception was thrown or not.

Exception Handling in Dart

Here is an example of how exception handling is done in Dart:

try {
  // code that might throw an exception
} catch (e) {
  // handle the exception
} finally {
  // code that will be executed regardless of whether an exception was thrown or not
}

The 'try' block contains code that might throw an exception. If an exception is thrown, execution of the 'try' block is stopped and control is passed to the 'catch' block. The 'catch' block is used to handle the exception. The 'finally' block is executed regardless of whether an exception was thrown or not.

Exception Handling Example

Let's consider an example where we are trying to divide a number by zero. We know that division by zero is undefined, so this will throw an exception.

void main() {
  int num1 = 10;
  int num2 = 0;
  int result;

  try {
    result = num1 ~/ num2;
    print('The result is $result');
  } catch (e) {
    print('Exception Caught: Division by Zero');
  } finally {
    print('This is the Finally block and will always be executed.');
  }
}

In this example, division by zero throws an exception. Since we are catching the exception in the 'catch' block, the exception is handled and the program is not interrupted. The 'finally' block is executed regardless of whether an exception was thrown or not.

Types of Exceptions in Dart

Dart provides many types of built-in exceptions such as IntegerDivisionByZeroException, IOException, TimeoutException, etc. We can also define our own custom exceptions by creating a new exception class.

Conclusion

Exception handling is a crucial aspect of object-oriented programming in Dart. It allows us to handle errors and exceptions in a controlled way, without interrupting the normal flow of the program. Dart provides several exception blocks and types to handle different error scenarios.

Understanding exception handling is essential to building robust and resilient applications in Flutter using Dart. This allows us to create a smooth user experience, handling possible errors and exceptions efficiently.