Simple Code

Multi-format code editor and viewer for Android

An Android editor and viewer for structured text files, built with Kotlin and Jetpack Compose.

The layout follows the single panel editor of jsoneditoronline.org: a sticky two row header above an editing surface with line numbers, syntax highlighting and block folding.

Supported formats Format Also covers JSON GeoJSON, TopoJSON XML GPX, KML, SVG, RSS HTML XHTML CSS JavaScript CSV TSV Markdown Plain text A markdown document is shown as it will be read as well as as it is written, by a toggle in the second row of the header that no other format offers. The rendered document goes into a frame that is allowed nothing: no script of its own runs and it cannot reach the page that holds it, which carries the bridge to the application. A markdown file can come from anywhere.

View modes Text for every format.

Tree for the nested formats, JSON and XML. Branches open and close one by one or all at once, XML attributes hang under their element marked with a leading sign, and a document that does not read cleanly says so rather than showing half of itself.

A name or a value is edited by tapping it, which is the gesture a phone has where the editor this follows has a double click. What is typed is written into the document in place of the few characters the name or the value occupied, and nothing else is touched: comments, declaration and layout come through an edit unchanged. The type of a JSON value follows what is typed, so a value becomes a number, a boolean or null by being written as one; text that would be read as one of those and is meant as a string is typed between quotes. Renaming an XML element carries its closing tag along. An edit is one step in the history, and there is no separate way to cancel one: undoing is the way back.

A long press on a node opens what can be done to it, which is the gesture a phone has where the editor this follows has a right click: edit the key or the value, copy, cut, paste, duplicate, extract the subtree as the whole document, remove, and insert an object, an array or a value before, after or inside. Copying and pasting go through the clipboard of the system, so a subtree travels to and from anywhere else. Each of these is one step in the history, and each is a handful of characters moved in the document, the punctuation between entries included: what surrounds the node keeps its comments and its layout.

Sorting and transforming are not offered on a node. The toolbar sorts and filters the whole document, and doing it to one branch would mean writing that branch out again, which would cost it the layout every other move here is careful to keep.

Table for CSV, which can be edited either as raw text or as a grid of rows and columns. The grid reads the first row as the column titles, keeps the quoting rules of the format on the way back out, and only quotes the fields that need it.

Sort and filter ask what to work on: a column for CSV, and for JSON the member its elements share, or the values themselves when they have none. An object is sorted and filtered by its keys. Both rewrite the document, so a filter that drops rows is undone in one step like any other edit, and a JSON document written on one line is written back on one line.

The second toolbar row adapts to the open document: a tool that has no meaning for the current format, such as the table mode on an HTML file, is not offered.

Settings Interface language: English by default, French and Spanish available. Theme: system, light or dark. Indentation width. Updates: automatic or manual. Left to itself the application looks once as it opens and says nothing unless there is something to say; asked to wait, it waits for the button under the choice. CSV separator: comma, semicolon or tab. A document that is opened keeps the separator it was written with, which the reader works out on its own; this choice is what a new document gets, what an opened one falls back to when nothing can be worked out, and what the open document is rewritten with when the choice changes.