How to set formatted JSON response string in a TextView?

Question

How to display JSON response string with formatting something similar to https://jsonformatter.org/json-parser ?

For example: How to display following code in textview ?

{
    "age":100,
    "name":"mkyong.com",
    "messages":["msg 1","msg 2","msg 3"]
}

P.S: Preferably color formatted.

In short ..

1.How to format and display JSON string ?
2.How to format and display Java code ?

Answer 1

I wrote the following utility method to format and indent (no colors yet):

public static String formatString(String text){

    StringBuilder json = new StringBuilder();
    String indentString = "";

    for (int i = 0; i < text.length(); i++) {
        char letter = text.charAt(i);
        switch (letter) {
            case '{':
            case '[':
                json.append("\n" + indentString + letter + "\n");
                indentString = indentString + "\t";
                json.append(indentString);
                break;
            case '}':
            case ']':
                indentString = indentString.replaceFirst("\t", "");
                json.append("\n" + indentString + letter);
                break;
            case ',':
                json.append(letter + "\n" + indentString);
                break;

            default:
                json.append(letter);
                break;
        }
    }

    return json.toString();
}

Answer 2

Much simpler approch, there is a toString method with indent space param for JSONObject,

can be used like this :

JSONObject jsonObject = new JSONObject(jsonString);
textView.setText(jsonObject.toString(4));// 4 is number of spaces for indent

same is applicable for JSONArray

reference :

https://developer.android.com/reference/org/json/JSONObject#toString(int)

https://alvinalexander.com/android/android-json-print-json-string-human-readable-format-debugging