Fix for android compilation issue with Lamda warning

Just in case anyone else comes accross this issue - I was having difficulty compiling for Android despite using Java version 1.8 and having a minimum SDK build of API 24. I reverted the Lamda functions to Runnable classes which seems to have worked.

Thanks to @claudiofelber for this flutter package! It has been an absolute life saver after file_picker stopped working.

Happy to create a PR if this is in any way helpful.

`package ch.perron2.lean_file_picker;

import android.app.Activity; import android.content.ContentResolver; import android.content.Intent; import android.database.Cursor; import android.net.Uri; import android.provider.OpenableColumns; import android.util.Log; import android.webkit.MimeTypeMap; import androidx.annotation.NonNull; import io.flutter.embedding.engine.plugins.FlutterPlugin; import io.flutter.embedding.engine.plugins.activity.ActivityAware; import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding; import io.flutter.plugin.common.EventChannel; import io.flutter.plugin.common.MethodCall; import io.flutter.plugin.common.MethodChannel; import io.flutter.plugin.common.MethodChannel.MethodCallHandler; import io.flutter.plugin.common.MethodChannel.Result; import io.flutter.plugin.common.PluginRegistry; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.util.ArrayList; import java.util.Collections; import java.util.List;

public class LeanFilePickerPlugin implements FlutterPlugin, MethodCallHandler, ActivityAware, PluginRegistry.ActivityResultListener { private static final String TAG = LeanFilePickerPlugin.class.getSimpleName(); // Random number to prevent clashes with other plugins because Flutter does // not (yet) provide a mechanism to cleanly allocate unique request codes // for calls to startActivityForResult(). private static final int REQUEST_OPEN_DOCUMENT = 487314648;

private MethodChannel channel;
private EventChannel.EventSink eventSink;
private Activity activity;
private Result result;

@Override
public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
    channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), "lean_file_picker");
    channel.setMethodCallHandler(this);
    EventChannel eventChannel = new EventChannel(
        flutterPluginBinding.getBinaryMessenger(), "lean_file_picker_events");
    eventChannel.setStreamHandler(new EventChannel.StreamHandler() {
        @Override
        public void onListen(Object arguments, EventChannel.EventSink events) {
            LeanFilePickerPlugin.this.eventSink = events;
        }

        @Override
        public void onCancel(Object arguments) {
            LeanFilePickerPlugin.this.eventSink = null;
        }
    });
}

@Override
public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
    this.result = result;
    if (call.method.equals("pickFile")) {
        List<String> extensions = call.argument("allowedExtensions");
        if (extensions == null) {
            extensions = Collections.emptyList();
        }
        List<String> mimeTypes = call.argument("allowedMimeTypes");
        if (mimeTypes == null) {
            mimeTypes = Collections.emptyList();
        }
        pickFile(extensions, mimeTypes);
    } else {
        result.notImplemented();
    }
}

@Override
public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
    channel.setMethodCallHandler(null);
}

@Override
public void onAttachedToActivity(@NonNull ActivityPluginBinding binding) {
    activity = binding.getActivity();
    binding.addActivityResultListener(this);
}

@Override
public void onDetachedFromActivityForConfigChanges() {
}

@Override
public void onReattachedToActivityForConfigChanges(@NonNull ActivityPluginBinding binding) {
}

@Override
public void onDetachedFromActivity() {
    activity = null;
}

private void pickFile(List<String> extensions, List<String> mimeTypes) {
    List<String> allMimeTypes = new ArrayList<>(extensions.size() + mimeTypes.size());
    allMimeTypes.addAll(mimeTypes);
    for (String extension : extensions) {
        String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
        if (mimeType != null) {
            allMimeTypes.add(mimeType);
        }
    }

    Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    intent.setType("*/*");
    if (!allMimeTypes.isEmpty()) {
        intent.putExtra(Intent.EXTRA_MIME_TYPES, allMimeTypes.toArray(new String[0]));
    }

    activity.startActivityForResult(intent, REQUEST_OPEN_DOCUMENT);
}

@Override
public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_OPEN_DOCUMENT) {
        if (resultCode == Activity.RESULT_OK && data != null) {
            final Uri documentUri = data.getData();
            if (documentUri != null) {
                String name = queryFileName(activity.getContentResolver(), documentUri);
                File cacheDir = activity.getCacheDir();
                final File outputFile = new File(cacheDir, name);
                eventSink.success(true);
                //Threads reverted to runnable anon classes in place of Lamda's
                new Thread(new Runnable() {
                    @Override
                    public void run(){
                        final boolean success = copyFile(documentUri, outputFile);
                        activity.runOnUiThread(new Runnable() {
                            @Override
                                    public void run(){
                                eventSink.success(false);
                                if (success) {
                                    result.success(outputFile.toString());
                                } else {
                                    result.success(null);
                                }
                            }

                        });
                    }
                }).start();
                return true;
            }
        }
        result.success(null);
        return true;
    }
    return false;
}

private String queryFileName(ContentResolver resolver, Uri uri) {
    Cursor returnCursor = resolver.query(uri, null, null, null, null);
    if (returnCursor != null) {
        int nameIndex = returnCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
        returnCursor.moveToFirst();
        String name = returnCursor.getString(nameIndex);
        returnCursor.close();
        return name;
    }
    return uri.getLastPathSegment();
}

private boolean copyFile(Uri sourceUri, File targetFile) {
    try (InputStream stream = activity.getContentResolver().openInputStream(sourceUri)) {
        try (FileOutputStream outStream = new FileOutputStream(targetFile)) {
            byte[] buffer = new byte[16 * 1024];
            int bytesRead;
            while ((bytesRead = stream.read(buffer)) != -1) {
                outStream.write(buffer, 0, bytesRead);
            }
        }
        return true;
    } catch (Exception ex) {
        Log.d(TAG, "Cannot copy selected file", ex);
    }
    return false;
}

} `

perron2 / lean-file-picker

Fix for android compilation issue with Lamda warning #1