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updating quick start

Anatoly Pulyaevskiy před 4 roky
rodič
revize
fde224e55c
5 změnil soubory, kde provedl 24 přidání a 11 odebrání
  1. binární
      .DS_Store
  2. 2
    1
      .gitignore
  3. binární
      assets/quick-start-rec-01.mp4
  4. binární
      assets/quick-start-rec-02.gif
  5. 22
    10
      doc/quick-start.md

binární
.DS_Store Zobrazit soubor


+ 2
- 1
.gitignore Zobrazit soubor

@@ -1 +1,2 @@
1
-.idea/
1
+.DS_Store
2
+.idea/

binární
assets/quick-start-rec-01.mp4 Zobrazit soubor


binární
assets/quick-start-rec-02.gif Zobrazit soubor


+ 22
- 10
doc/quick-start.md Zobrazit soubor

@@ -150,18 +150,23 @@ Here is how it might look when we run the app and navigate to editor page:
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151 151
 At this point we can already edit the document and apply styles, however if
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 we navigate back from this page our changes will be lost. Let's fix this and
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-add a button which saves the document to device's file system.
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+add a button which saves the document to the device's file system.
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-First we need a function to save the document:
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+First we need a function to save the document. Update `lib/src/editor_page.dart`
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+as follows:
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 ```dart
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+// change: add these two lines to imports section at the top of the file
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+import 'dart:convert'; // access to jsonEncode()
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+import 'dart:io'; // access to File and Directory classes
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+
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 class EditorPageState extends State<EditorPage> {
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-  // ... add after _loadDocument()
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+  // change: add after _loadDocument()
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   void _saveDocument(BuildContext context) {
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     // Notus documents can be easily serialized to JSON by passing to
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-    // `jsonEncode` directly:
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+    // `jsonEncode` directly
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     final contents = jsonEncode(_controller.document);
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     // For this example we save our document to a temporary file.
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     final file = File(Directory.systemTemp.path + "/quick_start.json");
@@ -173,8 +178,16 @@ class EditorPageState extends State<EditorPage> {
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 }
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 ```
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-> Notice that we pass `BuildContext` to `_saveDocument`. This is required
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-> to get access to our page's `Scaffold` state, so that we can show a `SnackBar`.
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+This function converts our document using `jsonEncode()` function and writes
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+the result to a file `quick_start.json` in the system's temporary directory.
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+
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+Note that `File.writeAsString` is an asynchronous method and returns Dart's
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+`Future`. This is why we register a completion callback with a call to
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+`Future.then`.
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+
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+One more important bit here is that we pass `BuildContext` argument to
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+`_saveDocument`. This is required to get access to our page's `Scaffold` state,
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+so that we can show a `SnackBar`.
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 Now we just need to add a button to the AppBar, so we need to modify `build`
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 method as follows:
@@ -182,7 +195,7 @@ method as follows:
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 ```dart
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 class EditorPageState extends State<EditorPage> {
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-  // ... replace build() method with following
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+  // change: replace build() method with following
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   @override
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   Widget build(BuildContext context) {
@@ -215,12 +228,11 @@ class EditorPageState extends State<EditorPage> {
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 ```
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217 230
 We have to use `Builder` here for our icon button because we need access to
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-build context within the scope of this page's Scaffold. Everything else here
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-should be straightforward.
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+build context which has access to `Scaffold` widget's state.
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 Now we can reload our app, hit "Save" button and see the snack bar.
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-<img src="https://github.com/memspace/zefyr/raw/gitbook/assets/quick-start-screen-02.png" width="375">
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+<img src="https://github.com/memspace/zefyr/raw/gitbook/assets/quick-start-rec-02.gif" width="600">
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225 237
 Since we now have this document saved to a file, let's update our
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 `_loadDocument` method to load saved file if it exists.