TunnelEditorFragment: add hooks for biometric auth

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

ui/src/main/java/com/wireguard/android/databinding/BindingAdapters.kt

@@ -6,6 +6,8 @@ package com.wireguard.android.databinding
 
 import android.text.InputFilter
 import android.view.LayoutInflater
+import android.view.View
+import android.widget.EditText
 import android.widget.LinearLayout
 import android.widget.TextView
 import androidx.databinding.BindingAdapter
@@ -13,6 +15,7 @@ import androidx.databinding.DataBindingUtil
 import androidx.databinding.ObservableList
 import androidx.databinding.ViewDataBinding
 import androidx.databinding.adapters.ListenerUtil
+import androidx.fragment.app.Fragment
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.wireguard.android.BR
@@ -41,10 +44,10 @@ object BindingAdapters {
     }
 
     @JvmStatic
-    @BindingAdapter("items", "layout")
+    @BindingAdapter("items", "layout", "fragment")
     fun <E> setItems(view: LinearLayout,
-                     oldList: ObservableList<E>?, oldLayoutId: Int,
+                     oldList: ObservableList<E>?, oldLayoutId: Int, @Suppress("UNUSED_PARAMETER") oldFragment: Fragment?,
-                     newList: ObservableList<E>?, newLayoutId: Int) {
+                     newList: ObservableList<E>?, newLayoutId: Int, newFragment: Fragment?) {
         if (oldList === newList && oldLayoutId == newLayoutId)
             return
         var listener: ItemChangeListener<E>? = ListenerUtil.getListener(view, R.id.item_change_listener)
@@ -59,7 +62,7 @@ object BindingAdapters {
         if (newList == null || newLayoutId == 0)
             return
         if (listener == null) {
-            listener = ItemChangeListener(view, newLayoutId)
+            listener = ItemChangeListener(view, newLayoutId, newFragment)
             ListenerUtil.trackListener(view, listener, R.id.item_change_listener)
         }
         // Either the list changed, or this is an entirely new listener because the layout changed.
@@ -123,6 +126,13 @@ object BindingAdapters {
         view.setOnBeforeCheckedChangeListener(listener)
     }
 
+    @JvmStatic
+    @BindingAdapter("onFocusChange")
+    fun setOnFocusChange(view: EditText,
+                         listener: View.OnFocusChangeListener?) {
+        view.setOnFocusChangeListener(listener)
+    }
+
     @JvmStatic
     @BindingAdapter("android:text")
     fun setText(view: TextView, text: Optional<*>) {

ui/src/main/java/com/wireguard/android/databinding/ItemChangeListener.kt

@@ -10,13 +10,14 @@ import android.view.ViewGroup
 import androidx.databinding.DataBindingUtil
 import androidx.databinding.ObservableList
 import androidx.databinding.ViewDataBinding
+import androidx.fragment.app.Fragment
 import com.wireguard.android.BR
 import java.lang.ref.WeakReference
 
 /**
  * Helper class for binding an ObservableList to the children of a ViewGroup.
  */
-internal class ItemChangeListener<T>(private val container: ViewGroup, private val layoutId: Int) {
+internal class ItemChangeListener<T>(private val container: ViewGroup, private val layoutId: Int, private val fragment: Fragment?) {
     private val callback = OnListChangedCallback(this)
     private val layoutInflater: LayoutInflater = LayoutInflater.from(container.context)
     private var list: ObservableList<T>? = null
@@ -29,6 +30,7 @@ internal class ItemChangeListener<T>(private val container: ViewGroup, private v
         require(list != null) { "Trying to get a view while list is still null" }
         binding!!.setVariable(BR.collection, list)
         binding.setVariable(BR.item, list!![position])
+        binding.setVariable(BR.fragment, fragment)
         binding.executePendingBindings()
         return binding.root
     }

ui/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.kt

@@ -6,6 +6,7 @@ package com.wireguard.android.fragment
 
 import android.content.Context
 import android.os.Bundle
+import android.text.InputType
 import android.util.Log
 import android.view.LayoutInflater
 import android.view.Menu
@@ -15,9 +16,9 @@ import android.view.View
 import android.view.ViewGroup
 import android.view.WindowManager
 import android.view.inputmethod.InputMethodManager
+import android.widget.EditText
 import android.widget.Toast
 import com.google.android.material.snackbar.Snackbar
-import com.google.android.material.textfield.TextInputLayout
 import com.wireguard.android.Application
 import com.wireguard.android.R
 import com.wireguard.android.backend.Tunnel
@@ -34,6 +35,7 @@ import com.wireguard.config.Config
  * Fragment for editing a WireGuard configuration.
  */
 class TunnelEditorFragment : BaseFragment(), AppExclusionListener {
+    private var haveShownKeys = false
     private var binding: TunnelEditorFragmentBinding? = null
     private var tunnel: ObservableTunnel? = null
     private fun onConfigLoaded(config: Config) {
@@ -76,7 +78,6 @@ class TunnelEditorFragment : BaseFragment(), AppExclusionListener {
             setUpScrollingContent(mainContainer, null)
             privateKeyTextLayout.setEndIconOnClickListener { config?.`interface`?.generateKeyPair() }
         }
-        requireActivity().window.addFlags(WindowManager.LayoutParams.FLAG_SECURE)
         return binding?.root
     }
 
@@ -226,6 +227,23 @@ class TunnelEditorFragment : BaseFragment(), AppExclusionListener {
         super.onViewStateRestored(savedInstanceState)
     }
 
+    fun onKeyClick(view: View) = onKeyFocusChange(view, true)
+
+    fun onKeyFocusChange(view: View, isFocused: Boolean) {
+        if (!isFocused) return
+        val edit = view as? EditText ?: return
+        if (!haveShownKeys && edit.text.isNotEmpty()) {
+            if (true /* TODO: do biometric auth prompt */) {
+                haveShownKeys = true
+            } else {
+                /* Unauthorized, so return and don't change visibility. */
+                return
+            }
+        }
+        requireActivity().window.addFlags(WindowManager.LayoutParams.FLAG_SECURE)
+        edit.inputType = InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS or InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD
+    }
+
     companion object {
         private const val KEY_LOCAL_CONFIG = "local_config"
         private const val KEY_ORIGINAL_NAME = "original_name"

ui/src/main/res/layout/tunnel_editor_fragment.xml

@@ -102,9 +102,11 @@
                                 android:id="@+id/private_key_text"
                                 android:layout_width="match_parent"
                                 android:layout_height="wrap_content"
-                                android:inputType="textNoSuggestions|textVisiblePassword"
+                                android:inputType="textNoSuggestions|textPassword"
+                                android:onClick="@{fragment::onKeyClick}"
                                 android:text="@={config.interface.privateKey}"
-                                app:filter="@{KeyInputFilter.newInstance()}" />
+                                app:filter="@{KeyInputFilter.newInstance()}"
+                                app:onFocusChange="@{fragment::onKeyFocusChange}" />
                         </com.google.android.material.textfield.TextInputLayout>
 
                         <com.google.android.material.textfield.TextInputLayout
@@ -234,6 +236,7 @@
                     android:layout_height="wrap_content"
                     android:divider="@null"
                     android:orientation="vertical"
+                    app:fragment="@{fragment}"
                     app:items="@{config.peers}"
                     app:layout="@{@layout/tunnel_editor_peer}"
                     tools:ignore="UselessLeaf" />

ui/src/main/res/layout/tunnel_editor_peer.xml

@@ -15,6 +15,10 @@
         <variable
             name="item"
             type="com.wireguard.android.viewmodel.PeerProxy" />
+
+        <variable
+            name="fragment"
+            type="com.wireguard.android.fragment.TunnelEditorFragment" />
     </data>
 
     <com.google.android.material.card.MaterialCardView
@@ -91,8 +95,11 @@
                     android:layout_width="match_parent"
                     android:layout_height="wrap_content"
                     android:hint="@string/hint_optional"
-                    android:inputType="textNoSuggestions|textVisiblePassword"
+                    android:inputType="textNoSuggestions|textPassword"
-                    android:text="@={item.preSharedKey}" />
+                    android:onClick="@{fragment::onKeyClick}"
+                    android:text="@={item.preSharedKey}"
+                    app:filter="@{KeyInputFilter.newInstance()}"
+                    app:onFocusChange="@{fragment::onKeyFocusChange}" />
             </com.google.android.material.textfield.TextInputLayout>
 
             <com.google.android.material.textfield.TextInputLayout