Feat: Support predicative back gesture

Fixes: #1103

app/src/main/AndroidManifest.xml

@@ -44,6 +44,7 @@
     <application
         android:allowBackup="true"
         android:banner="@drawable/banner"
+        android:enableOnBackInvokedCallback="true"
         android:fullBackupContent="true"
         android:icon="@mipmap/launcher_icon"
         android:label="@string/app_name"

app/src/main/java/me/zhanghai/android/files/filelist/FileListActivity.kt

@@ -43,13 +43,6 @@ class FileListActivity : AppActivity() {
         return super.onKeyUp(keyCode, event)
     }
 
-    override fun onBackPressed() {
-        if (fragment.onBackPressed()) {
-            return
-        }
-        super.onBackPressed()
-    }
-
     companion object {
         fun createViewIntent(path: Path): Intent =
             FileListActivity::class.createIntent()

app/src/main/java/me/zhanghai/android/files/filelist/FileListFragment.kt

@@ -27,6 +27,7 @@ import android.view.View
 import android.view.ViewGroup
 import android.widget.ProgressBar
 import android.widget.TextView
+import androidx.activity.OnBackPressedCallback
 import androidx.activity.result.contract.ActivityResultContract
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.annotation.RequiresApi
@@ -81,12 +82,14 @@ import me.zhanghai.android.files.settings.Settings
 import me.zhanghai.android.files.terminal.Terminal
 import me.zhanghai.android.files.ui.AppBarLayoutExpandHackListener
 import me.zhanghai.android.files.ui.CoordinatorAppBarLayout
+import me.zhanghai.android.files.ui.DrawerLayoutOnBackPressedCallback
 import me.zhanghai.android.files.ui.FixQueryChangeSearchView
 import me.zhanghai.android.files.ui.OverlayToolbarActionMode
 import me.zhanghai.android.files.ui.PersistentBarLayout
 import me.zhanghai.android.files.ui.PersistentBarLayoutToolbarActionMode
 import me.zhanghai.android.files.ui.PersistentDrawerLayout
 import me.zhanghai.android.files.ui.ScrollingViewOnApplyWindowInsetsListener
+import me.zhanghai.android.files.ui.SpeedDialViewOnBackPressedCallback
 import me.zhanghai.android.files.ui.ThemedFastScroller
 import me.zhanghai.android.files.ui.ToolbarActionMode
 import me.zhanghai.android.files.util.DebouncedRunnable
@@ -95,6 +98,7 @@ import me.zhanghai.android.files.util.Loading
 import me.zhanghai.android.files.util.ParcelableArgs
 import me.zhanghai.android.files.util.Stateful
 import me.zhanghai.android.files.util.Success
+import me.zhanghai.android.files.util.addOnBackPressedCallback
 import me.zhanghai.android.files.util.args
 import me.zhanghai.android.files.util.checkSelfPermission
 import me.zhanghai.android.files.util.copyText
@@ -248,6 +252,25 @@ class FileListFragment : Fragment(), BreadcrumbLayout.Listener, FileListAdapter.
             true
         }
 
+        val viewLifecycleOwner = viewLifecycleOwner
+        addOnBackPressedCallback(
+            object : OnBackPressedCallback(false) {
+                override fun handleOnBackPressed() {
+                    viewModel.navigateUp()
+                }
+            }
+                .also { callback ->
+                    viewModel.breadcrumbLiveData.observe(viewLifecycleOwner) {
+                        callback.isEnabled = viewModel.canNavigateUpBreadcrumb
+                    }
+                }
+        )
+        addOnBackPressedCallback(overlayActionMode.onBackPressedCallback)
+        addOnBackPressedCallback(SpeedDialViewOnBackPressedCallback(binding.speedDialView))
+        binding.drawerLayout?.let {
+            addOnBackPressedCallback(DrawerLayoutOnBackPressedCallback(it))
+        }
+
         if (!viewModel.hasTrail) {
             var path = argsPath
             val intent = args.intent
@@ -299,7 +322,6 @@ class FileListFragment : Fragment(), BreadcrumbLayout.Listener, FileListAdapter.
                 viewModel.pickOptions = pickOptions
             }
         }
-        val viewLifecycleOwner = viewLifecycleOwner
         viewModel.currentPathLiveData.observe(viewLifecycleOwner) { onCurrentPathChanged(it) }
         viewModel.searchViewExpandedLiveData.observe(viewLifecycleOwner) {
             onSearchViewExpandedChanged(it)
@@ -526,26 +548,6 @@ class FileListFragment : Fragment(), BreadcrumbLayout.Listener, FileListAdapter.
         return false
     }
 
-    fun onBackPressed(): Boolean {
-        val drawerLayout = binding.drawerLayout
-        if (drawerLayout != null && drawerLayout.isDrawerOpen(GravityCompat.START)) {
-            drawerLayout.closeDrawer(GravityCompat.START)
-            return true
-        }
-        if (binding.speedDialView.isOpen) {
-            binding.speedDialView.close()
-            return true
-        }
-        if (overlayActionMode.isActive) {
-            overlayActionMode.finish()
-            return true
-        }
-        if (viewModel.navigateUp(false)) {
-            return true
-        }
-        return false
-    }
-
     private fun onPersistentDrawerOpenChanged(open: Boolean) {
         binding.persistentDrawerLayout?.let {
             if (open) {
@@ -687,7 +689,7 @@ class FileListFragment : Fragment(), BreadcrumbLayout.Listener, FileListAdapter.
 
     private fun navigateUp() {
         collapseSearchView()
-        viewModel.navigateUp(true)
+        viewModel.navigateUp()
     }
 
     private fun showNavigateToPathDialog() {

app/src/main/java/me/zhanghai/android/files/filelist/FileListViewModel.kt

@@ -34,12 +34,7 @@ class FileListViewModel : ViewModel() {
 
     fun resetTo(path: Path) = trailLiveData.resetTo(path)
 
-    fun navigateUp(overrideBreadcrumb: Boolean): Boolean =
-        if (!overrideBreadcrumb && breadcrumbLiveData.valueCompat.selectedIndex == 0) {
-            false
-        } else {
-            trailLiveData.navigateUp()
-        }
+    fun navigateUp(): Boolean = trailLiveData.navigateUp()
 
     val currentPathLiveData = trailLiveData.map { it.currentPath }
     val currentPath: Path
@@ -102,6 +97,8 @@ class FileListViewModel : ViewModel() {
         }
 
     val breadcrumbLiveData: LiveData<BreadcrumbData> = BreadcrumbLiveData(trailLiveData)
+    val canNavigateUpBreadcrumb: Boolean
+        get() = breadcrumbLiveData.valueCompat.selectedIndex > 0
 
     private val _viewTypeLiveData = FileViewTypeLiveData(currentPathLiveData)
     val viewTypeLiveData: LiveData<FileViewType> = _viewTypeLiveData

app/src/main/java/me/zhanghai/android/files/ui/DrawerLayoutOnBackPressedCallback.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2024 Hai Zhang <dreaming.in.code.zh@gmail.com>
+ * All Rights Reserved.
+ */
+
+package me.zhanghai.android.files.ui
+
+import android.view.View
+import androidx.activity.OnBackPressedCallback
+import androidx.core.view.GravityCompat
+import androidx.drawerlayout.widget.DrawerLayout
+import androidx.drawerlayout.widget.DrawerLayout.SimpleDrawerListener
+
+class DrawerLayoutOnBackPressedCallback(
+    private val drawerLayout: DrawerLayout,
+    private val gravity: Int = GravityCompat.START
+) : OnBackPressedCallback(drawerLayout.isDrawerVisibleAndUnlocked(gravity)) {
+    init {
+        drawerLayout.addDrawerListener(
+            object : SimpleDrawerListener() {
+                override fun onDrawerOpened(drawerView: View) {
+                    isEnabled = drawerLayout.isDrawerVisibleAndUnlocked(gravity)
+                }
+
+                override fun onDrawerClosed(drawerView: View) {
+                    isEnabled = drawerLayout.isDrawerVisibleAndUnlocked(gravity)
+                }
+            }
+        )
+    }
+
+    override fun handleOnBackPressed() {
+        drawerLayout.closeDrawer(gravity)
+    }
+}
+
+private fun DrawerLayout.isDrawerVisibleAndUnlocked(gravity: Int): Boolean =
+    isDrawerVisible(gravity) && getDrawerLockMode(gravity) == DrawerLayout.LOCK_MODE_UNLOCKED

app/src/main/java/me/zhanghai/android/files/ui/SpeedDialViewOnBackPressedCallback.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2024 Hai Zhang <dreaming.in.code.zh@gmail.com>
+ * All Rights Reserved.
+ */
+
+package me.zhanghai.android.files.ui
+
+import androidx.activity.OnBackPressedCallback
+import com.leinardi.android.speeddial.SpeedDialView
+
+class SpeedDialViewOnBackPressedCallback(
+    private val speedDialView: SpeedDialView
+) : OnBackPressedCallback(speedDialView.isOpen) {
+    init {
+        speedDialView.setOnChangeListener(
+            object : SpeedDialView.OnChangeListener {
+                override fun onMainActionSelected(): Boolean = false
+
+                override fun onToggleChanged(isOpen: Boolean) {
+                    isEnabled = speedDialView.isOpen
+                }
+            }
+        )
+    }
+
+    override fun handleOnBackPressed() {
+        speedDialView.close()
+    }
+}

app/src/main/java/me/zhanghai/android/files/ui/ThemedSpeedDialView.kt

@@ -42,6 +42,8 @@ import me.zhanghai.android.files.util.shortAnimTime
 import me.zhanghai.android.files.util.withModulatedAlpha
 
 class ThemedSpeedDialView : SpeedDialView {
+    private var onChangeListener: OnChangeListener? = null
+
     private var mainFabAnimator: Animator? = null
 
     constructor(context: Context) : super(context)
@@ -86,8 +88,9 @@ class ThemedSpeedDialView : SpeedDialView {
         }
         mainFabAnimationRotateAngle = 0f
         setMainFabClosedDrawable(mainFabDrawable)
-        setOnChangeListener(object : OnChangeListener {
-            override fun onMainActionSelected(): Boolean = false
+        super.setOnChangeListener(object : OnChangeListener {
+            override fun onMainActionSelected(): Boolean =
+                onChangeListener?.onMainActionSelected() ?: false
 
             override fun onToggleChanged(isOpen: Boolean) {
                 mainFabAnimator?.cancel()
@@ -99,10 +102,15 @@ class ThemedSpeedDialView : SpeedDialView {
                     })
                     start()
                 }
+                onChangeListener?.onToggleChanged(isOpen)
             }
         })
     }
 
+    override fun setOnChangeListener(onChangeListener: OnChangeListener?) {
+        this.onChangeListener = onChangeListener
+    }
+
     private fun createMainFabAnimator(isOpen: Boolean): Animator =
         AnimatorSet().apply {
             playTogether(

app/src/main/java/me/zhanghai/android/files/ui/ToolbarActionMode.kt

@@ -8,6 +8,7 @@ import android.graphics.drawable.Drawable
 import android.view.Menu
 import android.view.MenuItem
 import android.view.ViewGroup
+import androidx.activity.OnBackPressedCallback
 import androidx.annotation.DrawableRes
 import androidx.annotation.MenuRes
 import androidx.annotation.StringRes
@@ -29,6 +30,12 @@ abstract class ToolbarActionMode(
         }
     }
 
+    val onBackPressedCallback: OnBackPressedCallback = object : OnBackPressedCallback(false) {
+        override fun handleOnBackPressed() {
+            finish()
+        }
+    }
+
     var navigationIcon: Drawable?
         get() = toolbar.navigationIcon
         set(value) {
@@ -78,6 +85,7 @@ abstract class ToolbarActionMode(
 
     fun start(callback: Callback, animate: Boolean = true) {
         this.callback = callback
+        onBackPressedCallback.isEnabled = true
         show(bar, animate)
         callback.onToolbarActionModeStarted(this)
     }
@@ -87,6 +95,7 @@ abstract class ToolbarActionMode(
     fun finish(animate: Boolean = true) {
         val callback = callback ?: return
         this.callback = null
+        onBackPressedCallback.isEnabled = false
         toolbar.menu.close()
         hide(bar, animate)
         callback.onToolbarActionModeFinished(this)

app/src/main/java/me/zhanghai/android/files/util/FragmentExtensions.kt

@@ -13,6 +13,7 @@ import android.os.Bundle
 import android.view.animation.Animation
 import android.view.animation.Interpolator
 import android.widget.Toast
+import androidx.activity.OnBackPressedCallback
 import androidx.annotation.AnimRes
 import androidx.annotation.AnyRes
 import androidx.annotation.ArrayRes
@@ -33,6 +34,10 @@ import me.zhanghai.android.files.compat.getColorCompat
 import me.zhanghai.android.files.compat.getColorStateListCompat
 import me.zhanghai.android.files.compat.getDrawableCompat
 
+fun Fragment.addOnBackPressedCallback(callback: OnBackPressedCallback) {
+    requireActivity().onBackPressedDispatcher.addCallback(viewLifecycleOwner, callback)
+}
+
 fun Fragment.checkSelfPermission(permission: String): Int =
     requireContext().checkSelfPermissionCompat(permission)
 

app/src/main/java/me/zhanghai/android/files/viewer/text/TextEditorActivity.kt

@@ -28,15 +28,8 @@ class TextEditorActivity : AppActivity() {
         }
     }
 
-    override fun onBackPressed() {
-        if (fragment.onFinish()) {
-            return
-        }
-        super.onBackPressed()
-    }
-
     override fun onSupportNavigateUp(): Boolean {
-        if (fragment.onFinish()) {
+        if (fragment.onSupportNavigateUp()) {
             return true
         }
         return super.onSupportNavigateUp()

app/src/main/java/me/zhanghai/android/files/viewer/text/TextEditorFragment.kt

@@ -14,6 +14,7 @@ import android.view.MenuItem
 import android.view.SubMenu
 import android.view.View
 import android.view.ViewGroup
+import androidx.activity.OnBackPressedCallback
 import androidx.appcompat.app.AppCompatActivity
 import androidx.core.view.children
 import androidx.core.widget.doAfterTextChanged
@@ -28,6 +29,7 @@ import me.zhanghai.android.files.ui.ThemedFastScroller
 import me.zhanghai.android.files.util.ActionState
 import me.zhanghai.android.files.util.DataState
 import me.zhanghai.android.files.util.ParcelableArgs
+import me.zhanghai.android.files.util.addOnBackPressedCallback
 import me.zhanghai.android.files.util.args
 import me.zhanghai.android.files.util.extraPath
 import me.zhanghai.android.files.util.fadeInUnsafe
@@ -48,6 +50,8 @@ class TextEditorFragment : Fragment(), ConfirmReloadDialogFragment.Listener,
 
     private val viewModel by viewModels { { TextEditorViewModel(argsFile) } }
 
+    private lateinit var onBackPressedCallback: OnBackPressedCallback
+
     private var isSettingText = false
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -56,6 +60,18 @@ class TextEditorFragment : Fragment(), ConfirmReloadDialogFragment.Listener,
         setHasOptionsMenu(true)
 
         lifecycleScope.launchWhenStarted {
+            onBackPressedCallback = object : OnBackPressedCallback(false) {
+                override fun handleOnBackPressed() {
+                    ConfirmCloseDialogFragment.show(this@TextEditorFragment)
+                }
+            }
+            launch {
+                viewModel.isTextChanged.collect {
+                    onBackPressedCallback.isEnabled = viewModel.isTextChanged.value
+                }
+            }
+            addOnBackPressedCallback(onBackPressedCallback)
+
             launch { viewModel.encoding.collect { onEncodingChanged(it) } }
             launch { viewModel.textState.collect { onTextStateChanged(it) } }
             launch { viewModel.isTextChanged.collect { onIsTextChangedChanged(it) } }
@@ -148,9 +164,9 @@ class TextEditorFragment : Fragment(), ConfirmReloadDialogFragment.Listener,
             else -> super.onOptionsItemSelected(item)
         }
 
-    fun onFinish(): Boolean {
-        if (viewModel.isTextChanged.value) {
-            ConfirmCloseDialogFragment.show(this)
+    fun onSupportNavigateUp(): Boolean {
+        if (onBackPressedCallback.isEnabled) {
+            onBackPressedCallback.handleOnBackPressed()
             return true
         }
         return false