Introduce and switch to FragmentViewBindingDelegate (#797)

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

app/build.gradle

@@ -80,6 +80,7 @@ dependencies {
     implementation deps.androidx.core_ktx
     implementation deps.androidx.documentfile
     implementation deps.androidx.fragment_ktx
+    implementation deps.androidx.lifecycle_common
     implementation deps.androidx.lifecycle_livedata_ktx
     implementation deps.androidx.lifecycle_viewmodel_ktx
     implementation deps.androidx.local_broadcast_manager

app/src/main/java/com/zeapo/pwdstore/PasswordFragment.kt

@@ -33,6 +33,7 @@ import com.zeapo.pwdstore.ui.adapters.PasswordItemRecyclerAdapter
 import com.zeapo.pwdstore.ui.dialogs.ItemCreationBottomSheet
 import com.zeapo.pwdstore.utils.PasswordItem
 import com.zeapo.pwdstore.utils.PasswordRepository
+import com.zeapo.pwdstore.utils.viewBinding
 import me.zhanghai.android.fastscroll.FastScrollerBuilder
 import java.io.File
 import java.util.Stack
@@ -44,10 +45,9 @@ class PasswordFragment : Fragment() {
 
     private var recyclerViewStateToRestore: Parcelable? = null
     private var actionMode: ActionMode? = null
-    private var _binding: PasswordRecyclerViewBinding? = null
 
     private val model: SearchableRepositoryViewModel by activityViewModels()
-    private val binding get() = _binding!!
+    private val binding by viewBinding(PasswordRecyclerViewBinding::bind)
 
     private fun requireStore() = requireActivity() as PasswordStore
 
@@ -56,7 +56,6 @@ class PasswordFragment : Fragment() {
         container: ViewGroup?,
         savedInstanceState: Bundle?
     ): View? {
-        _binding = PasswordRecyclerViewBinding.inflate(inflater, container, false)
         settings = PreferenceManager.getDefaultSharedPreferences(requireContext())
         initializePasswordList()
         binding.fab.setOnClickListener {
@@ -149,11 +148,6 @@ class PasswordFragment : Fragment() {
         }
     }
 
-    override fun onDestroyView() {
-        _binding = null
-        super.onDestroyView()
-    }
-
     private val actionModeCallback = object : ActionMode.Callback {
         // Called when the action mode is created; startActionMode() was called
         override fun onCreateActionMode(mode: ActionMode, menu: Menu): Boolean {

app/src/main/java/com/zeapo/pwdstore/ToCloneOrNot.kt

@@ -10,25 +10,19 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
-import kotlinx.android.synthetic.main.fragment_to_clone_or_not.clone_from_server_button
-import kotlinx.android.synthetic.main.fragment_to_clone_or_not.local_directory_button
-import kotlinx.android.synthetic.main.fragment_to_clone_or_not.settings_button
+import com.zeapo.pwdstore.databinding.FragmentToCloneOrNotBinding
+import com.zeapo.pwdstore.utils.viewBinding
 
 class ToCloneOrNot : Fragment() {
 
-    override fun onCreateView(
-        inflater: LayoutInflater,
-        container: ViewGroup?,
-        savedInstanceState: Bundle?
-    ): View? {
-        // Inflate the layout for this fragment
-        return inflater.inflate(R.layout.fragment_to_clone_or_not, container, false)
-    }
+    private val binding by viewBinding(FragmentToCloneOrNotBinding::bind)
+
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? = binding.root
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
-        settings_button.setOnClickListener { startActivity(Intent(requireContext(), UserPreference::class.java)) }
-        local_directory_button.setOnClickListener { (requireActivity() as PasswordStore).initRepository(PasswordStore.NEW_REPO_BUTTON) }
-        clone_from_server_button.setOnClickListener { (requireActivity() as PasswordStore).initRepository(PasswordStore.CLONE_REPO_BUTTON) }
+        binding.settingsButton.setOnClickListener { startActivity(Intent(requireContext(), UserPreference::class.java)) }
+        binding.localDirectoryButton.setOnClickListener { (requireActivity() as PasswordStore).initRepository(PasswordStore.NEW_REPO_BUTTON) }
+        binding.cloneFromServerButton.setOnClickListener { (requireActivity() as PasswordStore).initRepository(PasswordStore.CLONE_REPO_BUTTON) }
     }
 }

app/src/main/java/com/zeapo/pwdstore/autofill/oreo/ui/AutofillFilterActivity.kt

@@ -36,6 +36,7 @@ import com.zeapo.pwdstore.autofill.oreo.DirectoryStructure
 import com.zeapo.pwdstore.autofill.oreo.FormOrigin
 import com.zeapo.pwdstore.databinding.ActivityOreoAutofillFilterBinding
 import com.zeapo.pwdstore.utils.PasswordItem
+import com.zeapo.pwdstore.utils.viewBinding
 
 @TargetApi(Build.VERSION_CODES.O)
 class AutofillFilterView : AppCompatActivity() {
@@ -72,7 +73,7 @@ class AutofillFilterView : AppCompatActivity() {
 
     private lateinit var formOrigin: FormOrigin
     private lateinit var directoryStructure: DirectoryStructure
-    private lateinit var binding: ActivityOreoAutofillFilterBinding
+    private val binding by viewBinding(ActivityOreoAutofillFilterBinding::inflate)
 
     private val model: SearchableRepositoryViewModel by viewModels {
         ViewModelProvider.AndroidViewModelFactory(application)
@@ -80,7 +81,6 @@ class AutofillFilterView : AppCompatActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        binding = ActivityOreoAutofillFilterBinding.inflate(layoutInflater)
         setContentView(binding.root)
         setFinishOnTouchOutside(true)
 

app/src/main/java/com/zeapo/pwdstore/autofill/oreo/ui/AutofillPublisherChangedActivity.kt

@@ -22,6 +22,7 @@ import com.zeapo.pwdstore.autofill.oreo.AutofillPublisherChangedException
 import com.zeapo.pwdstore.autofill.oreo.FormOrigin
 import com.zeapo.pwdstore.autofill.oreo.computeCertificatesHash
 import com.zeapo.pwdstore.databinding.ActivityOreoAutofillPublisherChangedBinding
+import com.zeapo.pwdstore.utils.viewBinding
 
 @TargetApi(Build.VERSION_CODES.O)
 class AutofillPublisherChangedActivity : AppCompatActivity() {
@@ -45,11 +46,10 @@ class AutofillPublisherChangedActivity : AppCompatActivity() {
     }
 
     private lateinit var appPackage: String
-    private lateinit var binding: ActivityOreoAutofillPublisherChangedBinding
+    private val binding by viewBinding(ActivityOreoAutofillPublisherChangedBinding::inflate)
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        binding = ActivityOreoAutofillPublisherChangedBinding.inflate(layoutInflater)
         setContentView(binding.root)
         setFinishOnTouchOutside(true)
 

app/src/main/java/com/zeapo/pwdstore/git/GitConfigActivity.kt

@@ -14,15 +14,15 @@ import com.google.android.material.snackbar.Snackbar
 import com.zeapo.pwdstore.R
 import com.zeapo.pwdstore.databinding.ActivityGitConfigBinding
 import com.zeapo.pwdstore.utils.PasswordRepository
+import com.zeapo.pwdstore.utils.viewBinding
 import org.eclipse.jgit.lib.Constants
 
 class GitConfigActivity : BaseGitActivity() {
 
-    private lateinit var binding: ActivityGitConfigBinding
+    private val binding by viewBinding(ActivityGitConfigBinding::inflate)
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        binding = ActivityGitConfigBinding.inflate(layoutInflater)
         setContentView(binding.root)
         supportActionBar?.setDisplayHomeAsUpEnabled(true)
 

app/src/main/java/com/zeapo/pwdstore/git/GitServerConfigActivity.kt

@@ -17,6 +17,7 @@ import com.zeapo.pwdstore.databinding.ActivityGitCloneBinding
 import com.zeapo.pwdstore.git.config.ConnectionMode
 import com.zeapo.pwdstore.git.config.Protocol
 import com.zeapo.pwdstore.utils.PasswordRepository
+import com.zeapo.pwdstore.utils.viewBinding
 import java.io.IOException
 
 /**
@@ -25,11 +26,10 @@ import java.io.IOException
  */
 class GitServerConfigActivity : BaseGitActivity() {
 
-    private lateinit var binding: ActivityGitCloneBinding
+    private val binding by viewBinding(ActivityGitCloneBinding::inflate)
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        binding = ActivityGitCloneBinding.inflate(layoutInflater)
         val isClone = intent?.extras?.getInt(REQUEST_ARG_OP) ?: -1 == REQUEST_CLONE
         if (isClone) {
             binding.saveButton.text = getString(R.string.clone_button)

app/src/main/java/com/zeapo/pwdstore/sshkeygen/SshKeyGenFragment.kt

@@ -19,6 +19,7 @@ import com.jcraft.jsch.JSch
 import com.jcraft.jsch.KeyPair
 import com.zeapo.pwdstore.R
 import com.zeapo.pwdstore.databinding.FragmentSshKeygenBinding
+import com.zeapo.pwdstore.utils.viewBinding
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -28,17 +29,9 @@ import java.io.FileOutputStream
 class SshKeyGenFragment : Fragment() {
 
     private var keyLength = 4096
-    private var _binding: FragmentSshKeygenBinding? = null
-    private val binding get() = _binding!!
+    private val binding by viewBinding(FragmentSshKeygenBinding::bind)
 
-    override fun onCreateView(
-        inflater: LayoutInflater,
-        container: ViewGroup?,
-        savedInstanceState: Bundle?
-    ): View? {
-        _binding = FragmentSshKeygenBinding.inflate(inflater, container, false)
-        return binding.root
-    }
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?) = binding.root
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
@@ -60,7 +53,6 @@ class SshKeyGenFragment : Fragment() {
 
     override fun onDestroyView() {
         super.onDestroyView()
-        _binding = null
     }
 
     // Invoked when 'Generate' button of SshKeyGenFragment clicked. Generates a

app/src/main/java/com/zeapo/pwdstore/utils/FragmentViewBindingDelegate.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package com.zeapo.pwdstore.utils
+
+
+import android.view.LayoutInflater
+import android.view.View
+import androidx.appcompat.app.AppCompatActivity
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.observe
+import androidx.viewbinding.ViewBinding
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+/**
+ * Imported from https://medium.com/@Zhuinden/simple-one-liner-viewbinding-in-fragments-and-activities-with-kotlin-961430c6c07c
+ */
+class FragmentViewBindingDelegate<T : ViewBinding>(
+    val fragment: Fragment,
+    val viewBindingFactory: (View) -> T
+) : ReadOnlyProperty<Fragment, T> {
+
+    private var binding: T? = null
+
+    init {
+        fragment.lifecycle.addObserver(object : DefaultLifecycleObserver {
+            override fun onCreate(owner: LifecycleOwner) {
+                fragment.viewLifecycleOwnerLiveData.observe(fragment) { viewLifecycleOwner ->
+                    viewLifecycleOwner.lifecycle.addObserver(object : DefaultLifecycleObserver {
+                        override fun onDestroy(owner: LifecycleOwner) {
+                            binding = null
+                        }
+                    })
+                }
+            }
+        })
+    }
+
+    override fun getValue(thisRef: Fragment, property: KProperty<*>): T {
+        val binding = binding
+        if (binding != null) {
+            return binding
+        }
+
+        val lifecycle = fragment.viewLifecycleOwner.lifecycle
+        if (!lifecycle.currentState.isAtLeast(Lifecycle.State.INITIALIZED)) {
+            throw IllegalStateException("Should not attempt to get bindings when Fragment views are destroyed.")
+        }
+
+        return viewBindingFactory(thisRef.requireView()).also { this.binding = it }
+    }
+}
+
+fun <T : ViewBinding> Fragment.viewBinding(viewBindingFactory: (View) -> T) =
+    FragmentViewBindingDelegate(this, viewBindingFactory)
+
+inline fun <T : ViewBinding> AppCompatActivity.viewBinding(crossinline bindingInflater: (LayoutInflater) -> T) =
+    lazy(LazyThreadSafetyMode.NONE) {
+        bindingInflater.invoke(layoutInflater)
+    }

dependencies.gradle

@@ -32,6 +32,7 @@ ext.deps = [
         core_ktx: 'androidx.core:core-ktx:1.3.0-rc01',
         documentfile: 'androidx.documentfile:documentfile:1.0.1',
         fragment_ktx: 'androidx.fragment:fragment-ktx:1.3.0-alpha03',
+        lifecycle_common: 'androidx.lifecycle:lifecycle-common-java8:2.3.0-alpha01',
         lifecycle_livedata_ktx: 'androidx.lifecycle:lifecycle-livedata-ktx:2.3.0-alpha01',
         lifecycle_viewmodel_ktx: 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.0-alpha01',
         local_broadcast_manager: 'androidx.localbroadcastmanager:localbroadcastmanager:1.1.0-alpha01',