app: add a folder picker for local paths0.1.0

Typing absolute paths is error-prone; let the user browse real
filesystem folders and pick one. Stays on real paths (no SAF) so
rsync keeps operating on POSIX paths.

2 files changed, 110 insertions, 0 deletions

diff --git a/app/src/main/java/invalid/lena/rsend/FolderEditActivity.kt b/app/src/main/java/invalid/lena/rsend/FolderEditActivity.kt
index 2fe2b1b..c61276c 100644
--- a/app/src/main/java/invalid/lena/rsend/FolderEditActivity.kt
+++ b/app/src/main/java/invalid/lena/rsend/FolderEditActivity.kt
@@ -1,11 +1,14 @@
 package invalid.lena.rsend
 
+import android.app.Activity
+import android.content.Intent
 import android.os.Bundle
 import android.view.View
 import android.widget.Button
 import android.widget.EditText
 import android.widget.Switch
 import android.widget.Toast
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.appcompat.app.AppCompatActivity
 import java.io.File
 
@@ -20,6 +23,17 @@ class FolderEditActivity : AppCompatActivity() {
     private lateinit var excludes: EditText
     private lateinit var delete: Switch
 
+    // The picker returns a real filesystem path; drop it into the local field and
+    // name the folder after its basename if the name is still blank.
+    private val pickFolder =
+        registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
+            if (result.resultCode == Activity.RESULT_OK) {
+                val path = result.data?.getStringExtra("path") ?: return@registerForActivityResult
+                local.setText(path)
+                if (name.text.isNullOrBlank()) name.setText(File(path).name)
+            }
+        }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_folder)
@@ -43,6 +57,13 @@ class FolderEditActivity : AppCompatActivity() {
             delete.isChecked = f.delete
         }
 
+        findViewById<Button>(R.id.browse).setOnClickListener {
+            pickFolder.launch(
+                Intent(this, FolderPickerActivity::class.java)
+                    .putExtra("start", local.text.toString().trim())
+            )
+        }
+
         findViewById<Button>(R.id.save).setOnClickListener { saveFolder(); finish() }
         val del = findViewById<Button>(R.id.removeFolder)
         del.visibility = if (index < 0) View.GONE else View.VISIBLE
diff --git a/app/src/main/java/invalid/lena/rsend/FolderPickerActivity.kt b/app/src/main/java/invalid/lena/rsend/FolderPickerActivity.kt
new file mode 100644
index 0000000..1adccf3
--- /dev/null
+++ b/app/src/main/java/invalid/lena/rsend/FolderPickerActivity.kt
@@ -0,0 +1,89 @@
+package invalid.lena.rsend
+
+import android.content.Intent
+import android.os.Bundle
+import android.os.Environment
+import android.os.storage.StorageManager
+import android.widget.Button
+import android.widget.TextView
+import androidx.activity.addCallback
+import androidx.appcompat.app.AppCompatActivity
+import java.io.File
+
+// FolderPickerActivity browses the real filesystem and returns one directory's
+// absolute path in the "path" result extra. The app holds all-files access, so
+// rsync works on real paths; this picker stays on real paths too (no SAF, no
+// content URIs). Browsing is rooted at primary shared storage and cannot go
+// above it; SD cards and other volumes are still reachable by typing the path.
+class FolderPickerActivity : AppCompatActivity() {
+
+    private lateinit var pathView: TextView
+    private lateinit var list: android.widget.LinearLayout
+    private lateinit var root: File
+    private lateinit var current: File
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_picker)
+        setSupportActionBar(findViewById(R.id.toolbar))
+        title = "Pick folder"
+        fitSystemBars()
+        pathView = findViewById(R.id.currentPath)
+        list = findViewById(R.id.list)
+
+        root = getSystemService(StorageManager::class.java).primaryStorageVolume.directory
+            ?: Environment.getExternalStorageDirectory()
+
+        // Start where the field already points, if that is a directory under the
+        // root; otherwise at the root itself.
+        val start = intent.getStringExtra("start")?.let { File(it) }
+        current = if (start != null && start.isDirectory &&
+            start.absolutePath.startsWith(root.absolutePath)) start else root
+
+        findViewById<Button>(R.id.use).setOnClickListener {
+            setResult(RESULT_OK, Intent().putExtra("path", current.absolutePath))
+            finish()
+        }
+        findViewById<Button>(R.id.cancel).setOnClickListener { finish() }
+
+        // Hardware back walks up the tree until the root, then leaves the screen.
+        onBackPressedDispatcher.addCallback(this) {
+            if (current.absolutePath != root.absolutePath) {
+                current = current.parentFile ?: root
+                render()
+            } else {
+                isEnabled = false
+                onBackPressedDispatcher.onBackPressed()
+            }
+        }
+
+        render()
+    }
+
+    private fun render() {
+        pathView.text = current.absolutePath
+        list.removeAllViews()
+
+        if (current.absolutePath != root.absolutePath && current.parentFile != null) {
+            addRow("..", current.parentFile!!)
+        }
+
+        val dirs = current.listFiles { f -> f.isDirectory }
+            ?.sortedBy { it.name.lowercase() } ?: emptyList()
+        for (d in dirs) addRow(d.name, d)
+
+        if (dirs.isEmpty()) {
+            list.addView(TextView(this).apply {
+                text = "No subfolders here. Tap \"Use this folder\" to pick it."
+                setTextAppearance(R.style.TextAppearance_Rsend_Caption)
+            })
+        }
+    }
+
+    private fun addRow(label: String, dir: File) {
+        val row = layoutInflater.inflate(R.layout.item_dir, list, false)
+        row.findViewById<TextView>(R.id.dirName).text = label
+        row.setOnClickListener { current = dir; render() }
+        list.addView(row)
+    }
+}