Terminal-like app : UItextFied vs UITextView - ios

Question

Thanks in advance for your help. I try to boost my learning curve of Objective-c and defy myself with a lot of cases.
I try to do a simple app which simulates the comportment of a terminal session:
First step: a prompt is waiting and I enter a first command: eg. date. Then I get a result. Second: a prompt is waiting again below the result. Then I give a second command: time
etc.
I did a lot of tests with an UItextField to input different texts and commands, and a UITextView to display the results. I also use an NSMutable Array to stock all inputs/results. Nothing work very well. I would like to get your advice on that matter and that you point me the best approach or a code source to learn to reproduce a terminal gui. Is an array a good solution, how to place the textField at the end of the textView, etc.? Thanks+

Answer 1

This is just a general approach of what you want to achieve.
Use a single UITextView for input and output.
At first, add a simple character to your UITextView, for example ">", so the user starts typing after this character.
Implement this UITextView delegate method to listen on when the user taps "return" :
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
if([text isEqualToString:#"\n"]) {
// Handle what happens when user presses return
return NO;
}
return YES;
}
What I would do here is when the user presses return, get the whole UITextField's content, and use something like NSArray *stringArray = [_textField.text componentsSeparatedByString: #">"];. That way, the last element of your array is the last command the user entered. Then, test the command and append the appropriate answer to the UITextView. Don't forget to add #"\n>" after it so you prompt the user a new command line.
What's left to do here is prevent the user from erasing your ">".
It's an idea, there's probably many other ways to do it. Comment if you need more details on something !
SPOILER ALERT : full code
In my storyboard, I simply have a UITextView linked to ViewController.h, with the name textView. Note that the following code does not handle the user removing text from the UITextView. You can test the code by typing "hello" in the console.
ViewController.m :
#import "ViewController.h"
#interface ViewController () {
// Store supported commands and outputs
NSDictionary *commands;
}
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Initialize textView
_textView.text = #">";
[_textView becomeFirstResponder];
// Init supported commands with associated output
commands = [NSDictionary dictionaryWithObjectsAndKeys:#"Hello World !", #"hello", nil];
}
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
// Deleting something
if([text isEqualToString:#""]) {
UITextPosition *beginning = textView.beginningOfDocument;
UITextPosition *start = [textView positionFromPosition:beginning offset:range.location];
UITextPosition *end = [textView positionFromPosition:start offset:range.length];
UITextRange *textRange = [textView textRangeFromPosition:start toPosition:end];
NSString *textToReplace = [textView textInRange:textRange];
NSLog(#"%#", textToReplace);
if ([textToReplace isEqualToString:#">"]) return NO;
return YES;
}
if([text isEqualToString:#"\n"]) {
// Handle what happens when user presses return
NSArray *stringArray = [_textView.text componentsSeparatedByString: #">"];
NSLog(#"Last command : %#", [stringArray lastObject]);
[self handleCommand:[stringArray lastObject]];
return NO;
}
return YES;
}
-(void)handleCommand:(NSString*)command {
NSString *output = [commands objectForKey:command];
// If an unsupported command was typed
if (output == nil) {
output = #"Unknown command";
}
// Write output to the textView
_textView.text = [_textView.text stringByAppendingString:#"\n"];
_textView.text = [_textView.text stringByAppendingString:output];
_textView.text = [_textView.text stringByAppendingString:#"\n>"];
}
This is the textView's content from the simulator :
>hello
Hello World !
>yes
Unknown command
>
Unknown command
>hello
Hello World !

Answer 2

Many ways to do this. If I were doing it I think I would do the following:
A dictionary to hold the input and output for each command
Very large UITextView with all entries in the dictionary outputted in the format you like
A no border UITextField to act as the prompt.
You would have to write the following:
A method to place the UITextFiled at the right line of the UITextField
A method to populate the Diciotnary
A method to populate the UITextField from the dictionary