files

android/src/main/AndroidManifest.xml

@@ -1,3 +1,15 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="io.swipelab.ux">
+
+  <application>
+    <provider
+      android:name="androidx.core.content.FileProvider"
+      android:authorities="${applicationId}.ux.fileprovider"
+      android:exported="false"
+      android:grantUriPermissions="true">
+      <meta-data
+        android:name="android.support.FILE_PROVIDER_PATHS"
+        android:resource="@xml/ux_file_paths" />
+    </provider>
+  </application>
 </manifest>

android/src/main/kotlin/io/swipelab/ux/FilePlugin.kt

@@ -0,0 +1,131 @@
+package io.swipelab.ux
+
+import android.app.Activity
+import android.content.ActivityNotFoundException
+import android.content.Context
+import android.content.Intent
+import android.webkit.MimeTypeMap
+import androidx.core.content.FileProvider
+import io.flutter.embedding.engine.plugins.FlutterPlugin
+import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import java.io.File
+
+class FilePlugin : NativePlugin, MethodChannel.MethodCallHandler {
+    private var methodChannel: MethodChannel? = null
+    private var context: Context? = null
+    private var activity: Activity? = null
+
+    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+        context = binding.applicationContext
+        methodChannel = MethodChannel(binding.binaryMessenger, "ux/file").also {
+            it.setMethodCallHandler(this)
+        }
+    }
+
+    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+        methodChannel?.setMethodCallHandler(null)
+        methodChannel = null
+        context = null
+    }
+
+    override fun onAttachedToActivity(binding: ActivityPluginBinding) {
+        activity = binding.activity
+    }
+
+    override fun onDetachedFromActivity() {
+        activity = null
+    }
+
+    override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
+        when (call.method) {
+            "share" -> handleShare(call, result)
+            "open" -> handleOpen(call, result)
+            else -> result.notImplemented()
+        }
+    }
+
+    private fun handleShare(call: MethodCall, result: MethodChannel.Result) {
+        val ctx = context ?: return result.error("no_context", "no application context", null)
+        val act = activity ?: return result.error("no_activity", "plugin not attached to an activity", null)
+        val path = call.argument<String>("path")
+            ?: return result.error("bad_args", "path is required", null)
+        val title = call.argument<String>("title")
+        val mimeType = call.argument<String>("mimeType")
+
+        val authority = "${ctx.packageName}.ux.fileprovider"
+        val uri = try {
+            FileProvider.getUriForFile(ctx, authority, File(path))
+        } catch (e: IllegalArgumentException) {
+            return result.error("bad_path", "file is outside FileProvider paths: ${e.message}", null)
+        }
+
+        val intent = Intent(Intent.ACTION_SEND).apply {
+            type = mimeType ?: "*/*"
+            putExtra(Intent.EXTRA_STREAM, uri)
+            title?.let { putExtra(Intent.EXTRA_SUBJECT, it) }
+            addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+        }
+
+        val chooser = Intent.createChooser(intent, title).apply {
+            addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+        }
+        act.startActivity(chooser)
+        result.success(true)
+    }
+
+    private fun handleOpen(call: MethodCall, result: MethodChannel.Result) {
+        val ctx = context ?: return result.error("no_context", "no application context", null)
+        val act = activity ?: return result.error("no_activity", "plugin not attached to an activity", null)
+        val path = call.argument<String>("path")
+            ?: return result.error("bad_args", "path is required", null)
+        val mimeType = inferMime(call.argument<String>("mimeType"), path)
+
+        val authority = "${ctx.packageName}.ux.fileprovider"
+        val uri = try {
+            FileProvider.getUriForFile(ctx, authority, File(path))
+        } catch (e: IllegalArgumentException) {
+            return result.error("bad_path", "file is outside FileProvider paths: ${e.message}", null)
+        }
+
+        val intent = Intent(Intent.ACTION_VIEW).apply {
+            setDataAndType(uri, mimeType)
+            addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_ACTIVITY_NEW_TASK)
+        }
+        try {
+            act.startActivity(intent)
+            result.success(true)
+        } catch (_: ActivityNotFoundException) {
+            result.success(false)
+        }
+    }
+
+    private fun inferMime(supplied: String?, path: String): String {
+        if (!supplied.isNullOrBlank() && supplied != "application/octet-stream") {
+            return supplied
+        }
+        val dot = path.lastIndexOf('.')
+        val ext = if (dot in 0 until path.length - 1) path.substring(dot + 1).lowercase() else ""
+        if (ext.isNotEmpty()) {
+            val guessed = MimeTypeMap.getSingleton().getMimeTypeFromExtension(ext)
+            if (!guessed.isNullOrBlank()) return guessed
+            if (ext in textExtensions) return "text/plain"
+        }
+        return supplied ?: "*/*"
+    }
+
+    companion object {
+        private val textExtensions = setOf(
+            "dart", "swift", "kt", "kts", "java", "scala", "groovy",
+            "py", "rb", "php", "pl", "sh", "bash", "zsh", "fish",
+            "ts", "tsx", "jsx", "mjs", "cjs",
+            "go", "rs", "c", "h", "cpp", "hpp", "cc", "hh", "m", "mm",
+            "lua", "tcl", "r", "ex", "exs", "elm", "hs", "clj", "cljs", "scm",
+            "proto", "thrift", "sql",
+            "yml", "yaml", "toml", "ini", "conf", "cfg", "env", "properties",
+            "gradle", "lock", "diff", "patch",
+            "md", "markdown", "log", "txt",
+        )
+    }
+}

android/src/main/kotlin/io/swipelab/ux/UxPlugin.kt

@@ -8,6 +8,7 @@ class UxPlugin : FlutterPlugin, ActivityAware {
     private val plugins: List<NativePlugin> = listOf(
         KeyboardPlugin(),
         SensorPlugin(),
+        FilePlugin(),
     )
 
     override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) =

android/src/main/res/xml/ux_file_paths.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths>
+  <cache-path name="ux_share" path="ux_share/" />
+  <external-cache-path name="ux_share_ext" path="ux_share/" />
+</paths>