Save edited HTML on configuration changed

rich-html-editor/src/main/java/com/infomaniak/lib/richhtmleditor/EditorReloader.kt

@@ -0,0 +1,92 @@
+package com.infomaniak.lib.richhtmleditor
+
+import android.os.Looper
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.launch
+
+/**
+ * A utility class to help easily reload the html content of a [RichHtmlEditorWebView] on configuration changes.
+ *
+ * This class is meant to be instantiated inside a ViewModel to be able to retain the HTML content through configuration changes.
+ *
+ * @param coroutineScope A coroutine scope where the exportation of the HTML will be processed. Preferably the viewModelScope of
+ * the ViewModel where this class has been instantiated.
+ *
+ * @see load
+ * @see save
+ */
+class EditorReloader(private val coroutineScope: CoroutineScope) {
+
+    private var needToReloadHtml: Boolean = false
+    private var savedHtml = MutableStateFlow<String?>(null)
+
+    /**
+     * An alternative for loading the HTML content of the [RichHtmlEditorWebView].
+     *
+     * This method can be called within the `onViewCreated()` method of the Fragment containing your [RichHtmlEditorWebView].
+     * On the initial call, it loads the default HTML content. For all subsequent calls, it reloads the previously loaded HTML
+     * content.
+     *
+     * @param editor The editor to load content into.
+     * @param defaultHtml The HTML to load on the initial call. On subsequent calls, this value won't be taken into account.
+     *
+     * Usage:
+     * ```
+     * override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+     *     super.onViewCreated(view, savedInstanceState)
+     *     lifecycleScope.launch {
+     *         viewModel.editorReloader.load(editor, "<p>Hello World</p>")
+     *     }
+     * }
+     * ```
+     *
+     * @throws IllegalStateException If the method is not called on the main thread.
+     */
+    suspend fun load(editor: RichHtmlEditorWebView, defaultHtml: String) {
+        if (Looper.myLooper() != Looper.getMainLooper()) error("The load method needs to be called on the main thread")
+
+        if (needToReloadHtml) {
+            savedHtml.collectLatest {
+                if (it == null) return@collectLatest
+
+                resetSavedHtml()
+                editor.setHtml(it)
+            }
+        } else {
+            editor.setHtml(defaultHtml)
+        }
+
+        enableHtmlReload()
+    }
+
+    /**
+     * Exports and saves the editor's HTML content for later reloading.
+     *
+     * This method should be called within the `onSaveInstanceState()` method of the Fragment.
+     *
+     * @param editor The editor whose content needs to be saved.
+     *
+     * Usage:
+     * ```
+     * override fun onSaveInstanceState(outState: Bundle) {
+     *     super.onSaveInstanceState(outState)
+     *     viewModel.editorReloader.save(editor)
+     * }
+     * ```
+     */
+    fun save(editor: RichHtmlEditorWebView) {
+        editor.exportHtml {
+            coroutineScope.launch { savedHtml.emit(it) }
+        }
+    }
+
+    private suspend fun resetSavedHtml() {
+        savedHtml.emit(null)
+    }
+
+    private fun enableHtmlReload() {
+        needToReloadHtml = true
+    }
+}

sample/src/main/java/com/infomaniak/lib/richhtmleditor/sample/EditorSampleFragment.kt

@@ -10,6 +10,7 @@ import android.view.inputmethod.InputMethodManager
 import androidx.core.view.forEach
 import androidx.core.view.isVisible
 import androidx.fragment.app.Fragment
+import androidx.fragment.app.activityViewModels
 import androidx.lifecycle.lifecycleScope
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.infomaniak.lib.richhtmleditor.sample.databinding.CreateLinkTextInputBinding
@@ -22,6 +23,8 @@ class EditorSampleFragment : Fragment() {
     private var _binding: FragmentEditorSampleBinding? = null
     private val binding get() = _binding!! // This property is only valid between onCreateView and onDestroyView
 
+    private val editorSampleViewModel: EditorSampleViewModel by activityViewModels()
+
     private val createLinkDialog by lazy { CreateLinkDialog() }
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
@@ -31,25 +34,28 @@ class EditorSampleFragment : Fragment() {
     override fun onViewCreated(view: View, savedInstanceState: Bundle?): Unit = with(binding) {
         super.onViewCreated(view, savedInstanceState)
 
-        val html = readAsset("example1.html")
-
         setToolbarEnabledStatus(false)
+
+        setEditorContent()
         editor.apply {
             // You can add custom scripts and css such as:
             // addCss(readAsset("editor_custom_css.css"))
             // addScript("document.body.style['background'] = '#00FFFF'")
 
-            setHtml(html)
-
             isVisible = true
-
             setOnFocusChangeListener { _, hasFocus -> setToolbarEnabledStatus(hasFocus) }
         }
 
         setEditorButtonClickListeners()
         observeEditorStatusUpdates()
     }
 
+    private fun setEditorContent() {
+        lifecycleScope.launch {
+            editorSampleViewModel.editorReloader.load(binding.editor, readAsset("example1.html"))
+        }
+    }
+
     private fun setEditorButtonClickListeners() = with(binding) {
         buttonBold.setOnClickListener { editor.toggleBold() }
         buttonItalic.setOnClickListener { editor.toggleItalic() }
@@ -89,6 +95,11 @@ class EditorSampleFragment : Fragment() {
         }
     }
 
+    override fun onSaveInstanceState(outState: Bundle) {
+        editorSampleViewModel.editorReloader.save(binding.editor)
+        super.onSaveInstanceState(outState)
+    }
+
     override fun onDestroyView() {
         super.onDestroyView()
         _binding = null

sample/src/main/java/com/infomaniak/lib/richhtmleditor/sample/EditorSampleViewModel.kt

@@ -0,0 +1,9 @@
+package com.infomaniak.lib.richhtmleditor.sample
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.infomaniak.lib.richhtmleditor.EditorReloader
+
+class EditorSampleViewModel : ViewModel() {
+    val editorReloader = EditorReloader(viewModelScope)
+}