Parser du Json avec MIT App Inventor

Bonsoir,

Je crois que ce qui suit est un objet Json (je m'initie) qui renferme selon moi 7 objets.

Code:

{"blues":[{"id":"1","codeb":7000001,"prenom":"je","nom":"test","piece":"v","datecreation":"1989-12-11T23:00:00.000Z","datesortie":"1990-12-12T23:00:00.000Z","dateretour":"1990-12-13T23:00:00.000Z","etat":"g"},{"id":"1","codeb":7000002,"prenom":"je","nom":"test","piece":"v","datecreation":"1989-12-12T23:00:00.000Z","datesortie":"1990-12-13T23:00:00.000Z","dateretour":"1990-12-14T23:00:00.000Z","etat":"g"},{"id":"1","codeb":7000003,"prenom":"je","nom":"test","piece":"v","datecreation":"1989-12-13T23:00:00.000Z","datesortie":"1990-12-14T23:00:00.000Z","dateretour":"1990-12-15T23:00:00.000Z","etat":"g"},{"id":"1","codeb":7000004,"prenom":"je","nom":"test","piece":"p","datecreation":"1989-12-14T23:00:00.000Z","datesortie":"1990-12-15T23:00:00.000Z","dateretour":"1990-12-16T23:00:00.000Z","etat":"g"},{"id":"1","codeb":7000022,"prenom":"je","nom":"test","piece":"p","datecreation":"1989-12-15T23:00:00.000Z","datesortie":"1990-12-16T23:00:00.000Z","dateretour":"1990-12-17T23:00:00.000Z","etat":"g"},{"id":"1","codeb":7000005,"prenom":"je","nom":"test","piece":"p","datecreation":"1989-12-16T23:00:00.000Z","datesortie":"1990-12-17T23:00:00.000Z","dateretour":"1990-12-18T23:00:00.000Z","etat":"g"},{"id":"1","codeb":7000006,"prenom":"je","nom":"test","piece":"p","datecreation":"1989-12-17T23:00:00.000Z","datesortie":"1990-12-18T23:00:00.000Z","dateretour":"1990-12-19T23:00:00.000Z","etat":"g"}]}

Pour parser sur App Inventor on peut passer par l'utilisation des listes voir copie d'ecran jointe.

Pour l'instant je me contente de compter le nombre d'éléments de cette liste et j'obtiens 1.
Pièce jointe 481175

J'ai eu beau me triturer les méninges ou ce qu'il en reste, parcourir plusieurs forum, je ne comprends pas.

Merci à qui aura pris le temps de me lire