[file_selector] Add Android support

packages/file_selector/file_selector/.metadata

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+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled.
+
+version:
+  revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+  channel: stable
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+      base_revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+    - platform: android
+      create_revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+      base_revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'

packages/file_selector/file_selector_android/.metadata

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+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled.
+
+version:
+  revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+  channel: stable
+
+project_type: plugin
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+      base_revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+    - platform: android
+      create_revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+      base_revision: 4f9d92fbbdf072a70a70d2179a9f87392b94104c
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'

packages/file_selector/file_selector_android/AUTHORS

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+# Below is a list of people and organizations that have contributed
+# to the Flutter project. Names should be added to the list like so:
+#
+#   Name/Organization <email address>
+
+Google Inc.
+SOUTHWORKS <[email protected]>

packages/file_selector/file_selector_android/CHANGELOG.md

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+## 0.0.1
+
+* Initial Android implementation of `file_selector`.

packages/file_selector/file_selector_android/LICENSE

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+Copyright 2013 The Flutter Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+    * Neither the name of Google Inc. nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

packages/file_selector/file_selector_android/README.md

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+# file\_selector\_anrdoid
+
+The Android implementation of [`file_selector`][1].
+
+## Usage
+
+This package is [endorsed][2], which means you can simply use `file_selector`
+normally. This package will be automatically included in your app when you do.
+
+[1]: https://pub.dev/packages/file_selector
+[2]: https://flutter.dev/docs/development/packages-and-plugins/developing-packages#endorsed-federated-plugin

packages/file_selector/file_selector_android/android/.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+.DS_Store
+/build
+/captures
+.cxx

packages/file_selector/file_selector_android/android/build.gradle

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+group 'io.flutter.plugins.file_selector'
+version '1.0'
+
+buildscript {
+    repositories {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:7.1.2'
+    }
+}
+
+rootProject.allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+apply plugin: 'com.android.library'
+
+android {
+    compileSdkVersion 31
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    defaultConfig {
+        minSdkVersion 21
+    }
+
+    lintOptions {
+        disable 'InvalidPackage'
+        disable 'GradleDependency'
+    }
+
+    dependencies {
+        testImplementation 'junit:junit:4.13.2'
+        testImplementation 'org.mockito:mockito-core:4.8.0'
+        testImplementation 'androidx.test:core:1.4.0'
+        testImplementation "org.robolectric:robolectric:4.8.1"
+    }
+
+    testOptions {
+        unitTests.includeAndroidResources = true
+        unitTests.returnDefaultValues = true
+        unitTests.all {
+            testLogging {
+               events "passed", "skipped", "failed", "standardOut", "standardError"
+               outputs.upToDateWhen {false}
+               showStandardStreams = true
+            }
+        }
+    }
+}
+
+dependencies {
+    implementation project(path: ':flutter_plugin_android_lifecycle')
+}

packages/file_selector/file_selector_android/android/settings.gradle

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+rootProject.name = 'file_selector_android'

packages/file_selector/file_selector_android/android/src/main/AndroidManifest.xml

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+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+  package="io.flutter.plugins.file_selector">
+
+</manifest>

packages/file_selector/file_selector_android/android/src/main/java/io/flutter/plugins/file_selector/ActivityStateHelper.java

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+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.file_selector;
+
+import android.app.Activity;
+import android.app.Application;
+import androidx.annotation.VisibleForTesting;
+import androidx.lifecycle.Lifecycle;
+import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding;
+import io.flutter.embedding.engine.plugins.lifecycle.FlutterLifecycleAdapter;
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugin.common.MethodChannel;
+import io.flutter.plugin.common.PluginRegistry;
+
+/**
+ * Move all activity-lifetime-bound states into this helper object, so that {@code setup} and {@code
+ * tearDown} would just become constructor and finalize calls of the helper object.
+ */
+public class ActivityStateHelper {
+  private Application application;
+  private Activity activity;
+  private FileSelectorDelegate delegate;
+  private MethodChannel channel;
+  private LifeCycleHelper observer;
+  private ActivityPluginBinding activityBinding;
+
+  // This is null when not using v2 embedding;
+  private Lifecycle lifecycle;
+
+  // Default constructor
+  ActivityStateHelper(
+      final String CHANNEL,
+      final Application application,
+      final Activity activity,
+      final BinaryMessenger messenger,
+      final MethodChannel.MethodCallHandler handler,
+      final PluginRegistry.Registrar registrar,
+      final ActivityPluginBinding activityBinding) {
+    this.application = application;
+    this.activity = activity;
+    this.activityBinding = activityBinding;
+
+    delegate = constructDelegate(activity);
+    channel = new MethodChannel(messenger, CHANNEL);
+    channel.setMethodCallHandler(handler);
+    observer = new LifeCycleHelper(activity);
+    if (registrar != null) {
+      // V1 embedding setup for activity listeners.
+      application.registerActivityLifecycleCallbacks(observer);
+      registrar.addActivityResultListener(delegate);
+      registrar.addRequestPermissionsResultListener(delegate);
+    } else {
+      // V2 embedding setup for activity listeners.
+      activityBinding.addActivityResultListener(delegate);
+      activityBinding.addRequestPermissionsResultListener(delegate);
+      lifecycle = FlutterLifecycleAdapter.getActivityLifecycle(activityBinding);
+      lifecycle.addObserver(observer);
+    }
+  }
+
+  // Only invoked by {@link #FileSelectorPlugin(FileSelectorDelegate, Activity)}
+  // for testing.
+  ActivityStateHelper(final FileSelectorDelegate delegate, final Activity activity) {
+    this.activity = activity;
+    this.delegate = delegate;
+  }
+
+  void release() {
+    if (activityBinding != null) {
+      activityBinding.removeActivityResultListener(delegate);
+      activityBinding.removeRequestPermissionsResultListener(delegate);
+      activityBinding = null;
+    }
+
+    if (lifecycle != null) {
+      lifecycle.removeObserver(observer);
+      lifecycle = null;
+    }
+
+    if (channel != null) {
+      channel.setMethodCallHandler(null);
+      channel = null;
+    }
+
+    if (application != null) {
+      application.unregisterActivityLifecycleCallbacks(observer);
+      application = null;
+    }
+
+    activity = null;
+    observer = null;
+    delegate = null;
+  }
+
+  Activity getActivity() {
+    return activity;
+  }
+
+  FileSelectorDelegate getDelegate() {
+    return delegate;
+  }
+
+  @VisibleForTesting
+  FileSelectorDelegate constructDelegate(final Activity setupActivity) {
+    return new FileSelectorDelegate(setupActivity);
+  }
+}