[webview_flutter] Add file chooser on Android

packages/webview_flutter/webview_flutter/CHANGELOG.md

@@ -1,5 +1,6 @@
 ## NEXT
 
+* Add file chooser on Android
 * Updated Android lint settings.
 
 ## 2.0.12

packages/webview_flutter/webview_flutter/android/src/main/AndroidManifest.xml

@@ -1,2 +1,23 @@
-<manifest package="io.flutter.plugins.webviewflutter">
+<manifest package="io.flutter.plugins.webviewflutter"
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <application>
+        <activity
+            android:name="io.flutter.plugins.webviewflutter.RequestCameraPermissionActivity"
+            android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen" />
+        <activity
+            android:name="io.flutter.plugins.webviewflutter.FileChooserActivity"
+            android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen" />
+
+        <provider
+            android:name="io.flutter.plugins.webviewflutter.GenericFileProvider"
+            android:authorities="${applicationId}.generic.provider"
+            android:exported="false"
+            android:grantUriPermissions="true"
+            >
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/provider_paths"
+                />
+        </provider>
+    </application>
 </manifest>

packages/webview_flutter/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/Constants.java

@@ -0,0 +1,20 @@
+// 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.webviewflutter;
+
+public class Constants {
+  static final String ACTION_REQUEST_CAMERA_PERMISSION_FINISHED =
+      "action_request_camera_permission_denied";
+  static final String ACTION_FILE_CHOOSER_FINISHED = "action_file_chooser_completed";
+
+  static final String EXTRA_TITLE = "extra_title";
+  static final String EXTRA_ACCEPT_TYPES = "extra_types";
+  static final String EXTRA_SHOW_VIDEO_OPTION = "extra_show_video_option";
+  static final String EXTRA_SHOW_IMAGE_OPTION = "extra_show_image_option";
+  static final String EXTRA_FILE_URIS = "extra_file_uris";
+  static final String EXTRA_ALLOW_MULTIPLE_FILES = "extra_allow_multiple_files";
+
+  static final String WEBVIEW_STORAGE_DIRECTORY = "storage";
+}

packages/webview_flutter/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/FileChooserActivity.java

@@ -0,0 +1,220 @@
+// 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.webviewflutter;
+
+import static io.flutter.plugins.webviewflutter.Constants.ACTION_FILE_CHOOSER_FINISHED;
+import static io.flutter.plugins.webviewflutter.Constants.EXTRA_ACCEPT_TYPES;
+import static io.flutter.plugins.webviewflutter.Constants.EXTRA_ALLOW_MULTIPLE_FILES;
+import static io.flutter.plugins.webviewflutter.Constants.EXTRA_FILE_URIS;
+import static io.flutter.plugins.webviewflutter.Constants.EXTRA_SHOW_IMAGE_OPTION;
+import static io.flutter.plugins.webviewflutter.Constants.EXTRA_SHOW_VIDEO_OPTION;
+import static io.flutter.plugins.webviewflutter.Constants.EXTRA_TITLE;
+import static io.flutter.plugins.webviewflutter.Constants.WEBVIEW_STORAGE_DIRECTORY;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.Bundle;
+import android.provider.MediaStore;
+import android.provider.OpenableColumns;
+import android.util.Log;
+import androidx.annotation.Nullable;
+import androidx.core.content.FileProvider;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Date;
+
+public class FileChooserActivity extends Activity {
+
+  private static final String TAG = "FileChooserActivity";
+  private static final int FILE_CHOOSER_REQUEST_CODE = 12322;
+  private static final SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMdd_HHmmss");
+
+  // List of Uris that point to files where there MIGHT be the output of the capture. At most one of these can be valid
+  private final ArrayList<Uri> potentialCaptureOutputUris = new ArrayList<>();
+
+  @Override
+  protected void onCreate(@Nullable Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    showFileChooser(
+        getIntent().getBooleanExtra(EXTRA_SHOW_IMAGE_OPTION, false),
+        getIntent().getBooleanExtra(EXTRA_SHOW_VIDEO_OPTION, false));
+  }
+
+  private void showFileChooser(boolean showImageIntent, boolean showVideoIntent) {
+    Intent getContentIntent = createGetContentIntent();
+    Intent captureImageIntent =
+        showImageIntent ? createCaptureIntent(MediaStore.ACTION_IMAGE_CAPTURE, "jpg") : null;
+    Intent captureVideoIntent =
+        showVideoIntent ? createCaptureIntent(MediaStore.ACTION_VIDEO_CAPTURE, "mp4") : null;
+
+    if (getContentIntent == null && captureImageIntent == null && captureVideoIntent == null) {
+      // cannot open anything: cancel file chooser
+      sendBroadcast(new Intent(ACTION_FILE_CHOOSER_FINISHED));
+      finish();
+    } else {
+      ArrayList<Intent> intentList = new ArrayList<>();
+
+      if (getContentIntent != null) {
+        intentList.add(getContentIntent);
+      }
+
+      if (captureImageIntent != null) {
+        intentList.add(captureImageIntent);
+      }
+      if (captureVideoIntent != null) {
+        intentList.add(captureVideoIntent);
+      }
+
+      Intent chooserIntent = new Intent(Intent.ACTION_CHOOSER);
+      chooserIntent.putExtra(Intent.EXTRA_TITLE, getIntent().getStringExtra(EXTRA_TITLE));
+
+      chooserIntent.putExtra(Intent.EXTRA_INTENT, intentList.get(0));
+      intentList.remove(0);
+      if (intentList.size() > 0) {
+        chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentList.toArray(new Intent[0]));
+      }
+
+      startActivityForResult(chooserIntent, FILE_CHOOSER_REQUEST_CODE);
+    }
+  }
+
+  private Intent createGetContentIntent() {
+    Intent filesIntent = new Intent(Intent.ACTION_GET_CONTENT);
+
+    if (getIntent().getBooleanExtra(EXTRA_ALLOW_MULTIPLE_FILES, false)) {
+      filesIntent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
+    }
+
+    String[] acceptTypes = getIntent().getStringArrayExtra(EXTRA_ACCEPT_TYPES);
+
+    if (acceptTypes.length == 0 || (acceptTypes.length == 1 && acceptTypes[0].length() == 0)) {
+      // empty array or only 1 empty string? -> accept all types
+      filesIntent.setType("*/*");
+    } else if (acceptTypes.length == 1) {
+      filesIntent.setType(acceptTypes[0]);
+    } else {
+      // acceptTypes.length > 1
+      filesIntent.setType("*/*");
+      filesIntent.putExtra(Intent.EXTRA_MIME_TYPES, acceptTypes);
+    }
+
+    return (filesIntent.resolveActivity(getPackageManager()) != null) ? filesIntent : null;
+  }
+
+  private Intent createCaptureIntent(String type, String fileFormat) {
+    Intent captureIntent = new Intent(type);
+    if (captureIntent.resolveActivity(getPackageManager()) == null) {
+      return null;
+    }
+
+    // Create the File where the output should go
+    Uri captureOutputUri = getTempUri(fileFormat);
+    potentialCaptureOutputUris.add(captureOutputUri);
+
+    captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, captureOutputUri);
+
+    return captureIntent;
+  }
+
+  private File getStorageDirectory() {
+    File imageDirectory = new File(getCacheDir(), WEBVIEW_STORAGE_DIRECTORY);
+    if (!imageDirectory.exists() && !imageDirectory.mkdir()) {
+      Log.e(TAG, "Unable to create storage directory");
+    }
+    return imageDirectory;
+  }
+
+  private Uri getTempUri(String format) {
+    String fileName = "CAPTURE-" + simpleDateFormat.format(new Date()) + "." + format;
+    File file = new File(getStorageDirectory(), fileName);
+    return FileProvider.getUriForFile(
+        this, getApplicationContext().getPackageName() + ".generic.provider", file);
+  }
+
+  private String getFileNameFromUri(Uri uri) {
+    Cursor returnCursor = getContentResolver().query(uri, null, null, null, null);
+    assert returnCursor != null;
+    int nameIndex = returnCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
+    returnCursor.moveToFirst();
+    String name = returnCursor.getString(nameIndex);
+    returnCursor.close();
+    return name;
+  }
+
+  private Uri copyToLocalUri(Uri uri) {
+    File destination = new File(getStorageDirectory(), getFileNameFromUri(uri));
+
+    try (InputStream in = getContentResolver().openInputStream(uri);
+        OutputStream out = new FileOutputStream(destination)) {
+      byte[] buffer = new byte[1024];
+      int len;
+      while ((len = in.read(buffer)) != -1) {
+        out.write(buffer, 0, len);
+      }
+      return FileProvider.getUriForFile(
+          this, getApplicationContext().getPackageName() + ".generic.provider", destination);
+    } catch (IOException e) {
+      Log.e(TAG, "Unable to copy selected image", e);
+      e.printStackTrace();
+      return null;
+    }
+  }
+
+  @Override
+  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
+    if (requestCode == FILE_CHOOSER_REQUEST_CODE) {
+      Intent fileChooserFinishedIntent = new Intent(ACTION_FILE_CHOOSER_FINISHED);
+      if (resultCode == Activity.RESULT_OK) {
+        if (data != null && (data.getDataString() != null || data.getClipData() != null)) {
+          if (data.getDataString() != null) {
+            // single result from file browser OR video from camera
+            Uri localUri = copyToLocalUri(data.getData());
+            if (localUri != null) {
+              fileChooserFinishedIntent.putExtra(
+                  EXTRA_FILE_URIS, new String[] {localUri.toString()});
+            }
+          } else if (data.getClipData() != null) {
+            // multiple results from file browser
+            int uriCount = data.getClipData().getItemCount();
+            String[] uriStrings = new String[uriCount];
+
+            for (int i = 0; i < uriCount; i++) {
+              Uri localUri = copyToLocalUri(data.getClipData().getItemAt(i).getUri());
+              if (localUri != null) {
+                uriStrings[i] = localUri.toString();
+              }
+            }
+            fileChooserFinishedIntent.putExtra(EXTRA_FILE_URIS, uriStrings);
+          }
+        } else {
+          // image result from camera (videos from the camera are handled above, but this if-branch could handle them too if this varies from device to device)
+          for (Uri captureOutputUri : potentialCaptureOutputUris) {
+            try {
+              // just opening an input stream (and closing immediately) to test if the Uri points to a valid file
+              // if it's not a real file, the below catch-clause gets executed and we continue with the next Uri in the loop.
+              getContentResolver().openInputStream(captureOutputUri).close();
+              fileChooserFinishedIntent.putExtra(
+                  EXTRA_FILE_URIS, new String[] {captureOutputUri.toString()});
+              // leave the loop, as only one of the potentialCaptureOutputUris is valid and we just found it
+              break;
+            } catch (IOException ignored) {
+            }
+          }
+        }
+      }
+      sendBroadcast(fileChooserFinishedIntent);
+      finish();
+    } else {
+      super.onActivityResult(requestCode, resultCode, data);
+    }
+  }
+}