How do I put imageCache.clear(); into my Flutter app? Five of my six images are loading but one refusing to load. I tried flutter clean and restarting Android Studio. When I do this at the top of the program:
import 'package:flutter/material.dart';
imageCache.clear();
I get this error message:
lib/main.dart:2:19: Error: Expected a function body or '=>'.
Try adding {}.
imageCache.clear();
I tried this
imageCache.clear() {}
but that got a different error message.
You probably put the function in the wrong place.
You can put in the initState
void initState() {
super.initState();
imageCache.clear();
}
or wherever a function should be not where a widget should be.
Related
I'm using the Video Player package in Flutter.
My problem:
When the videoPlayerController is initialized with no/invalid data on iOS, the app silently crashes without any error message and doesn't leave any opportunity to react to the error by showing an error widget etc.
Here is my current approach to catch an error message out of this, but I think in case there IS an error/exception available, it would be written into the terminal anyway. Right now the error just kills the app silently with no chance to react to it...
Any suggestions? Thank you in advance!
//other code
..
..
controller = VideoPlayerController.asset("my_non_valid_asset");
controller?.initialize().catchError((onError) => throw Exception(
"catchError: VideoPlayerController couldn't get initialized. Maybe error with video data?"))
.onError((error, stackTrace) =>
throw Exception("onError: VideoPlayerController couldn't get initialized. Maybe error with video data?"));
Platform-specific errors are usually handled with the PlatformException class. But it totally depends on the author, the author is free to use any custom exception class by extending Exception class provided by Flutter framework.
I'm trying to build a Flutter web fr my app project.
After passing "Flutter Create ." and trying to run in Chrome it shows a blank page and stops on the web_entrypoint.dart file.
Anyone knows what could be wrong?
perhaps you want to remove the Future<void> before main
Future<void> main() async{} //<--- remove Future<void>
// do
void main() async{
/* body */
}
i am trying to find a way to take a screenshot of entire screen. Flutter library is only allowing me to make a screenshot of a widget, but i want a screenshot of entire android.
I did find this link:
How to programmatically take a screenshot on Android?
and this is resolwing my problem, but i tried to use that java code as it is in documentation:
https://flutter.dev/docs/development/platform-integration/platform-channels?tab=android-channel-java-tab
sadly i am not able to run that code, maybie im making some kind of mistakes? i find a error, while i whas following docs instruction, after that program whas working (not exacly, java whas not able to find my battery, but code whas compiling), and then i copy first answer from that stack link and i tried to pase it in "MainActivity" folder, sadly program whas not working, my "old" java code whas comipilng, from the docs, not the new one.
If you know the solution how to make a photo of entire android screen using some kind of buttor in flutter, or how to implement code from that link into my MainActivity.java folder, please help
Try this package native_screenshot
https://pub.dev/packages/native_screenshot
You can simply run this function to take the screenshot of your phone:
Future<void> _capturePng() async {
String path = await NativeScreenshot.takeScreenshot();
print(path);
}
You can learn more about this package here
It work fine with Android and IOS
Hope it will be useful
You can use screenshot plugin:https://pub.dev/packages/screenshot to take a widget screenshot.
A screenshot is a simple plugin to capture widgets as Images. This plugin wraps your widgets inside RenderRepaintBoundary
Use this package as a library
Add this to your package's pubspec.yaml file:
dependencies:
screenshot: ^0.2.0
Now in your Dart code, Import it:
import 'package:screenshot/screenshot.dart';
This handy plugin can be used to capture any Widget including full-screen screenshots & individual widgets like Text().
Create Instance of Screenshot Controller
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
File _imageFile;
//Create an instance of ScreenshotController
ScreenshotController screenshotController = ScreenshotController();
#override
void initState() {
// TODO: implement initState
super.initState();
}
...
}
Wrap the widget that you want to capture inside Screenshot Widget. Assign the controller to screenshotController that you have created earlier
Screenshot(
controller: screenshotController,
child: Text("This text will be captured as image"),
),
Take the screenshot by calling the capture method. This will return a File
screenshotController.capture().then((File image) {
//Capture Done
setState(() {
_imageFile = image;
});
}).catchError((onError) {
print(onError);
});
Duplicate: How to take a screenshot of the current widget - Flutter
I want to clear shared preferences when I send a FCM message and app is in background. Inside myBackgroundMessageHandler method I am calling a method to clear them.
static Future<dynamic> myBackgroundMessageHandler(
Map<String, dynamic> message) {
clearPreferences();
}
static void clearPreferences() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
prefs.clear();
}
I am getting the following error:
Unhandled Exception: MissingPluginException(No implementation found
for method getAll on channel plugins.flutter.io/shared_preferences)
step 1)
go to Application.kt/Application.java (in my case is kotlin)
step 2)
add these line into Application class (in kotlin)
if (!registry!!.hasPlugin("io.flutter.plugins.sharedpreferences")) {
SharedPreferencesPlugin.registerWith(registry!!.registrarFor("io.flutter.plugins.sharedpreferences.SharedPreferencesPlugin"));
}
remember import this as well
import io.flutter.plugins.sharedpreferences.SharedPreferencesPlugin
step 3)
run flutter clean -> flutter get -> uninstall your app
The code is completely fine.
Just restart your emulator. If you didn't do a full restart by closing the emulator and open it up again, this error can propably occur, because it doesnt have the newly added plugins.
Add SharedPreferences.setMockInitialValues({}) to your code before the runApp() function inside the main function of Flutter App.
this fixed the error for me
I am trying to force my Flutter app to only use Portrait mode. My main() method looks like this.
void main() {
SystemChrome.setSystemUIOverlayStyle(uiOverlayStyle);
SystemChrome.setPreferredOrientations(ALLOWED_ORIENTATIONS)
.then((_) => runApp(MyApp()));
}
Here is the definition of ALLOWED_ORIENTATIONS:
const List<DeviceOrientation> ALLOWED_ORIENTATIONS = [
DeviceOrientation.portraitUp
];
I just separated all the settings and such to another file to make modifying them later on easier.
When I run this code, I get the following error.
[VERBOSE-2:ui_dart_state.cc(157)] Unhandled Exception:
ServicesBinding.defaultBinaryMessenger was accessed before the binding was initialized.
If you're running an application and need to access the binary messenger before `runApp()`
has been called (for example, during plugin initialization), then you need to explicitly
call the `WidgetsFlutterBinding.ensureInitialized()` first.
It looks like there is some race condition that's failing. I am just not sure what is causing it. Removing the SystemChrome.setPreferredOrientations() line makes the app compile as expected. So, I am thinking the error has something to do with that line.
Any advice?
Like the error says
If you're running an application and need to access the binary
messenger before runApp() has been called (for example, during
plugin initialization), then you need to explicitly call the
WidgetsFlutterBinding.ensureInitialized() first.
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
SystemChrome.setSystemUIOverlayStyle(uiOverlayStyle);
await SystemChrome.setPreferredOrientations(ALLOWED_ORIENTATIONS);
runApp(MyApp());
}