I am not sure of the terminology for what I'm looking to do, so sorry in advance!
I've found a FilePicker plugin for Xamarin.Forms (https://github.com/Studyxnet/FilePicker-Plugin-for-Xamarin-and-Windows) that implements device-specific functionality for selecting files via the CrossFilePicker class.
The way to use leverage this functionality would be something like
CrossFilePicker.Current.OpenFile("Filename.txt");
The most important part of this for me is that CrossFilePicker.Current is static and can be accessible from anywhere in the shared layer of my Xamarin.Forms app.
I need to implement a class with the same characteristics. I want to leverage device Accessibility functionality (i.e. determining if a screen reader is enabled) and I need to be able to do so with a static class.
My eventual plan is to then wrap this static class so that I can use it for unit tests too.
I don't want to import device libraries into my shared project.
TLDR: I need a static class that implements device-specific functionality.
Any help would be greatly appreciated! Thank you :)
EDIT:
Here are the files I have currently implemented in my project
IAccessibilityService Located in the shared .NET project
namespace Bitspace.Services
{
public interface IAccessibilityService
{
public bool IsScreenReaderEnabled();
public void Announcement(string message);
public void NavigationAnnouncement(string message);
}
}
DeviceAccessibility.cs Located in the shared .NET project
using System;
namespace Bitspace.Services
{
public class DeviceAccessibility
{
private static Lazy<IAccessibilityService> Implementation = new Lazy<IAccessibilityService>(() => CreateAccessibilityService(), System.Threading.LazyThreadSafetyMode.PublicationOnly);
public static IAccessibilityService Current
{
get
{
var curr = Implementation.Value;
if (curr == null)
{
throw new Exception();
}
return curr;
}
}
private static IAccessibilityService CreateAccessibilityService()
{
return new DeviceAccessibilityImplementation();
}
}
}
DeviceAccessibilityImplementation.cs Located in the Android project
using Android.Runtime;
namespace Bitspace.Services
{
[Preserve (AllMembers = true)]
public class DeviceAccessibilityImplementation : IAccessibilityService
{
public bool IsScreenReaderEnabled()
{
return true;
}
public void Announcement(string message)
{
}
public void NavigationAnnouncement(string message)
{
}
}
}
If I try to build the project, I get an error on the return new DeviceAccessibilityImplementation(); line in DeviceAccessibility.cs that says DeviceAccessibility.cs(25, 24): [CS0246] The type or namespace name 'DeviceAccessibilityImplementation' could not be found (are you missing a using directive or an assembly reference?)
However, CTRL Clicking on that line takes me to the DeviceAccessibilityImplementation.cs
Godot version: 3.2.3
Issue description:
I am new at using Android Plugins in Godot, so I created this simple plugin with only one method.
public class GodotProva extends GodotPlugin
{
public GodotProva(Godot godot) {
super(godot);
}
#NonNull
#Override
public String getPluginName() {
return "mylibrary";
}
}
I tried to use it in Godot, with the following code:
func _pressed():
if Engine.has_singleton("mylibrary"):
var singleton = Engine.get_singleton("mylibrary")
print(singleton.getPluginName())
I created an apk and installed it on my Android device. The problem is that when I press the button (and the function _pressed() is called), I can see from the logcat the error Nonexistent function 'getPluginName' in base 'JNISingleton'
I am sure that the plugin is found, because the "singleton" variable is not null.
What am I doing wrong?
I found out that in Godot I can only call custom functions. The methods of the class GodotPlugin (such as getPluginName, getPluginMethods...) cannot be directly called.
In my case, I needed to define methods in getPluginMethods in my GodotPlugin like this:
public void firstMethod() {
// TODO
}
public void secondMethod() {
// TODO
}
#SuppressWarnings("deprecation")
#NonNull
#Override
public List<String> getPluginMethods() {
return Arrays.asList("firstMethod", "secondMethod");
}
I don't know why this case is not documented, but I wasted a lot of time on this and I think it would be useful for other people...
I'm following this tutorial and this Custom Detector Example in order to implement Custom Lint Rules. Basically what I've done is:
Create a new Android Project in Android Studio;
Create a java module for project created in step 1;
On module's build.gradle, import Lint API dependencies;
Create an Issue & IssueRegistry & CustomDetector;
Reference the IssueRegistry on module's build.gradle;
Create Unit tests;
My problem is, during the execution of my JUnits, I always receive "No Warning". When I debug the test, I can see that my Custom Detector isn't called, what am I doing wrong?
Strings.java
public class Strings {
public static final String STR_ISSUE_001_ID = "VarsMustHaveMoreThanOneCharacter";
public static final String STR_ISSUE_001_DESCRIPTION = "Avoid naming variables with only one character";
public static final String STR_ISSUE_001_EXPLANATION = "Variables named with only one character do not pass any meaning to the reader. " +
"Variables name should clear indicate the meaning of the value it is holding";
}
Issues.java
public class Issues {
public static final
Issue ISSUE_001 = Issue.create(
STR_ISSUE_001_ID,
STR_ISSUE_001_DESCRIPTION,
STR_ISSUE_001_EXPLANATION,
SECURITY,
// Priority ranging from 0 to 10 in severeness
6,
WARNING,
new Implementation(VariableNameDetector.class, ALL_RESOURCES_SCOPE)
);
}
IssuesRegistry.java
public class IssueRegistry extends com.android.tools.lint.client.api.IssueRegistry {
#Override
public List<Issue> getIssues() {
List<Issue> issues = new ArrayList<>();
issues.add(ISSUE_001);
return issues;
}
}
VariableNameDetector.java
public class VariableNameDetector extends Detector implements Detector.JavaScanner {
public VariableNameDetector() {
}
#Override
public boolean appliesToResourceRefs() {
return false;
}
#Override
public boolean appliesTo(Context context, File file) {
return true;
}
#Override
#Nullable
public AstVisitor createJavaVisitor(JavaContext context) {
return new NamingConventionVisitor(context);
}
#Override
public List<String> getApplicableMethodNames() {
return null;
}
#Override
public List<Class<? extends Node>> getApplicableNodeTypes() {
List<Class<? extends Node>> types = new ArrayList<>(1);
types.add(lombok.ast.VariableDeclaration.class);
return types;
}
#Override
public void visitMethod(
JavaContext context,
AstVisitor visitor,
MethodInvocation methodInvocation
) {
}
#Override
public void visitResourceReference(
JavaContext context,
AstVisitor visitor,
Node node,
String type,
String name,
boolean isFramework
) {
}
private class NamingConventionVisitor extends ForwardingAstVisitor {
private final JavaContext context;
NamingConventionVisitor(JavaContext context) {
this.context = context;
}
#Override
public boolean visitVariableDeclaration(VariableDeclaration node) {
StrictListAccessor<VariableDefinitionEntry, VariableDeclaration> varDefinitions =
node.getVariableDefinitionEntries();
for (VariableDefinitionEntry varDefinition : varDefinitions) {
String name = varDefinition.astName().astValue();
if (name.length() == 1) {
context.report(
ISSUE_001,
context.getLocation(node),
STR_ISSUE_001_DESCRIPTION
);
return true;
}
}
return false;
}
}
}
build.gradle
apply plugin: 'java'
configurations {
lintChecks
}
ext {
VERSION_LINT_API = '24.3.1'
VERSION_LINT_API_TESTS = '24.3.1'
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation "com.android.tools.lint:lint-api:$VERSION_LINT_API"
implementation "com.android.tools.lint:lint-checks:$VERSION_LINT_API"
testImplementation "com.android.tools.lint:lint-tests:$VERSION_LINT_API_TESTS"
}
jar {
manifest {
attributes('Lint-Registry': 'br.com.edsilfer.lint_rules.resources.IssueRegistry')
}
}
sourceCompatibility = "1.7"
targetCompatibility = "1.7"
TestVariableNameDetector.java
private static final String ARG_DEFAULT_LINT_SUCCESS_LOG = "No warnings.";
#Override
protected Detector getDetector() {
return new VariableNameDetector();
}
#Override
protected List<Issue> getIssues() {
return Collections.singletonList(Issues.ISSUE_001);
}
public void test_file_with_no_variables_with_length_equals_01() throws Exception {
assertEquals(
ARG_DEFAULT_LINT_SUCCESS_LOG,
lintProject(java("assets/Test.java", "public class Test {public String sampleVariable;}"))
);
}
public void test_file_with_variables_with_length_equals_01() throws Exception {
assertEquals(
ARG_DEFAULT_LINT_SUCCESS_LOG,
lintProject(java("assets/Test3.java", "public class Test {public String a;bnvhgvhj}"))
);
}
}
P.S.: on Java's module I do not have access to assetsor res folder, that is the reason why I've created a String.java and I'm using java(to, source) in my Unit test - I assumed that this java method does the same as the xml from the tutorial link I referenced at the top of this question.
It turned out that in my case the problem was with the JUnit itself. I think that the way I was attempting to simulate the file was wrong. The text below is part of the README.md of a sample project that I've created in order to document what I've learned from this API and answers the question in the title:
Create
Create a new Android Project;
Create a new Java Library Module - Custom Lint Rules are packaged into .jar libraries once they are ready, therefore the easiest way to implement them using them is inside a Java Module Library;
On module's build.gradle:
add target and source compatibility to Java 1.7;
add dependencies for lint-api, lint-checks and test dependencies;
add jar packing task containing two attributes: Manifest-Version and Lint-Registry, set the first to 1.0 and the second as the full path to a class that will later on contain the issue's catalog;
add a default tasl assemble;
[OPTIONAL]: add a task that will copy the generated .jar into ~/.android/lint;
Check REF001 and choose a Detector that best suits your needs, based on it create and implement a class to fulfill the Detector's role;
Still based on REF0001 chosen file, create and implement a Checker class, later referring to it inside Detector's createJavaVisitor() method;
for the sake of SRP, do not place Checker in the same file of Detector's class;
Copy the generated .jar file from build/lib to ~/.android/lint - if you added a task on build.gradle that does this you can skip this step;
Restart the computer - once created and moved into ~/.android/lint, the Custom Rules should be read by Lint next time the program starts. In order to have the alert boxes inside Android Studio, it is enough to invalidate caches and restart the IDE, however, to have your custom rules caught on Lint Report when ./gradlew check, it might be necessary to restart your computer;
Testing Detectors and Checkers
Testing Custom Rules is not an easy task to do - mainly due the lack of documentation for official APIs. This section will present two approaches for dealing with this. The main goal of this project is to create custom rules that will be run against real files, therefore, test files will be necessary for testing them. They can be places in src/test/resources folder from your Lint Java Library Module;
Approach 01: LintDetectorTest
Make sure you've added all test dependencies - checkout sample project's build.gradle;
Copy EnhancedLintDetectorTest.java and FileUtils.java into your project's test directory;
There is a known bug with Android Studio that prevents it from seeing files from src/test/resources folder, these files are a workaround for that;
EnhancedLintDetectorTest.java should return all issues that will be subject of tests. A nice way to do so is getting them from Issue Registry;
Create a test class that extends from EnhancedLintDetectorTest.java;
Implement getDetector() method returning an instance of the Detector to be tested;
Use lintFiles("test file path taking resources dir as root") to perform the check of the Custom Rules and use its result object to assert the tests;
Note that LintDetectorTest.java derives from TestCase.java, therefore, you're limited to JUnit 3.
Approach 02: Lint JUnit Rule
You might have noticed that Approach 01 might be a little overcomplicated, despite the fact that you're limited to JUnit 3 features. Because of that GitHub user a11n created a Lint JUnit Rule that allows the test of Custom Lint Rules in a easier way that counts with JUnit 4 and up features. Please, refer to his project README.md for details about how to create tests using this apprach.
Currently, Lint JUnit Rule do not correct the root dir for test files and you might no be able to see the tests passing from the IDE - however it works when test are run from command line. An issue and PR were created in order to fix this bug.
I'm not sure how to use the AST Api, however I'm personally using Psi and this is one of my lint checks that are working for me.
public final class RxJava2MethodCheckReturnValueDetector extends Detector implements Detector.JavaPsiScanner {
static final Issue ISSUE_METHOD_MISSING_CHECK_RETURN_VALUE =
Issue.create("MethodMissingCheckReturnValue", "Method is missing the #CheckReturnValue annotation",
"Methods returning RxJava Reactive Types should be annotated with the #CheckReturnValue annotation.",
MESSAGES, 8, WARNING,
new Implementation(RxJava2MethodCheckReturnValueDetector.class, EnumSet.of(JAVA_FILE, TEST_SOURCES)));
#Override public List<Class<? extends PsiElement>> getApplicablePsiTypes() {
return Collections.<Class<? extends PsiElement>>singletonList(PsiMethod.class);
}
#Override public JavaElementVisitor createPsiVisitor(#NonNull final JavaContext context) {
return new CheckReturnValueVisitor(context);
}
static class CheckReturnValueVisitor extends JavaElementVisitor {
private final JavaContext context;
CheckReturnValueVisitor(final JavaContext context) {
this.context = context;
}
#Override public void visitMethod(final PsiMethod method) {
final PsiType returnType = method.getReturnType();
if (returnType != null && Utils.isRxJava2TypeThatRequiresCheckReturnValueAnnotation(returnType)) {
final PsiAnnotation[] annotations = method.getModifierList().getAnnotations();
for (final PsiAnnotation annotation : annotations) {
if ("io.reactivex.annotations.CheckReturnValue".equals(annotation.getQualifiedName())) {
return;
}
}
final boolean isMethodMissingCheckReturnValueSuppressed = context.getDriver().isSuppressed(context, ISSUE_METHOD_MISSING_CHECK_RETURN_VALUE, method);
if (!isMethodMissingCheckReturnValueSuppressed) {
context.report(ISSUE_METHOD_MISSING_CHECK_RETURN_VALUE, context.getLocation(method.getNameIdentifier()), "Method should have #CheckReturnValue annotation");
}
}
}
}
}
Checkout the many more I wrote here.
I'm trying to use the LoaderManager in my code however I'm getting an incompatible types error:
#Override
public Loader<List<String>> onCreateLoader(int id, Bundle args) {
return new FileLoader(MainActivity.this);
}
shouldn't this statement return new FileLoader(MainActivity.this) returns a Loader? And here is the implementation of the LoaderManager:
public class FileLoader extends AsyncTaskLoader<List<String>>{
public FileLoader(Context context){
super(context);
}
#Override
public List<String> loadInBackground() {
.........
........
return listFiles;
}
}
I had the same problem(incompatible types required), but when see your post ,it helps me to learn more.In my code, it was imported:
"import androidx.loader.content.AsyncTaskLoader;"
, so i change it to:
"import android.content.AsyncTaskLoader;"
then my problem solved.
Because "AsyncTaskLoader" : This class was deprecated in API level 28,by below ref.
https://developer.android.com/reference/android/content/AsyncTaskLoader
by this advice,"You should also consider migrating existing projects to AndroidX", the webpage below:
https://developer.android.com/jetpack/androidx/migrate/class-mappings
finally I succeeded to solve the problem ... it was that didn't Import the support library in the AsyncTaskLoader file , while using it at the Main file ...so i just removed
import android.content.AsyncTaskLoader;
and Import the following support library
import android.support.v4.content.AsyncTaskLoader;
I'm currently trying to develop an application under Android using Mono.
I'd like to add support for plugins to my application so additional features could be brought to it.
I was able to load simple .dll at runtime in my program, however whenever I try creating a dll implementing both my interface and a custom activity, an exception of type Java.Lang.NoClassDefFoundError is thrown.
There is the class inside the dll code:
[Activity (Label = "Vestiaire")]
public class Vestiaire : Activity, IModule
{
public string Name { get; set; }
public string Version { get; set; }
void OnClickVestiaireButton(object sender, System.EventArgs e)
{
;
}
public void InitVestiaireModule()
{
Run();
}
public Type LaunchActivity ()
{
return typeof(Vestiaire);
}
public void Init()
{
Name = "Vestiaire Module";
Version = "0.1";
}
public void Run()
{
}
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
}
}
The line responsible for the exception: (from the program core)
LoadedPlugin.Add((IModule)(Activator.CreateInstance(Plugin)));
Things I'm actually wonderring are:
- Is it possible to actually achieve what i'm trying to ?
If yes, help would be apreciated on that problem :P
Otherwise what would be the best alternative ?
Global point is to be able to load a custom menu at runtime loaded from a dll.
Thanks.
i think the key to your problem is that the Activity needs to be registered in you Manifest.xml file.
For Activities in you main app, MonoDroid does this for you - but I don't think this will work for your plugin.
Things you could try are:
putting the Activity in the Manifest yourself (MonoDroid does seem very capable at merging these files)
if that doesn't work, then you could try using a Fragment instead - and loading the Fragment into a custom FragmentActivity in your main app.