react-native-android

问题 I want to build an app for coloring images in native android, which has images and I want to know how to detect the image borders, and how to detect different shapes and fill color in them? example app link : https://play.google.com/store/apps/details?id=kidgames.coloring.pages&hl=en 回答1: You can use Flood Fill Algorithm. see link: Flood Fill Algorithm private void FloodFill(Bitmap bmp, Point pt, int targetColor, int replacementColor){ Queue<Point> q = new LinkedList<Point>(); q.add(pt);

问题 I want to build an app for coloring images in native android, which has images and I want to know how to detect the image borders, and how to detect different shapes and fill color in them? example app link : https://play.google.com/store/apps/details?id=kidgames.coloring.pages&hl=en 回答1: You can use Flood Fill Algorithm. see link: Flood Fill Algorithm private void FloodFill(Bitmap bmp, Point pt, int targetColor, int replacementColor){ Queue<Point> q = new LinkedList<Point>(); q.add(pt);

问题 Trying to run react-native run-ios or build RN project from xcode, as soon as metro bundler starts, this error appears in the terminal: Loading dependency graph...jest-haste-map: Watchman crawl failed. Retrying once with node crawler. Usually this happens when watchman isn't running. Create an empty `.watchmanconfig` file in your project's root folder or initialize a git or hg repository in your project. Error: Watchman error: resolve_projpath: path `/Users/vorousjames/Desktop/Development

问题 I would try : Source ( Two function in a event on React-Native ) onValueChange={(selected) => { this.setState({selected}); this.state.eventOnChange(); }} But that's Not work That executes the first function , but not the second. 回答1: Component.setState() is asynchronous and may be locked on the second call while it is still doing the first. Do the second call in a callback like this: this.setState({selected},() => { this.state.eventOnChange(); }); 回答2: Try to log a console after all functions

问题 I have two tabbar : ListMusic | Favourite. When I add a song to favourite in tab ListMusic, how can I set listener for tab Favourite know that it need for reload to display new data. Thanks! 回答1: You can set one prop state which will be set on each change of ListMusic and use that prop in Favourite as key in render() 's parent view component. So, whenever state changes it will re-render Favourite. Example: render() { const unconfirmedErrorMsgToken = this.props.unconfirmedErrorMsgToken; return

问题 React native noob here , I wanna know if it's possible to use the FullTextSearch feature of sqlite in react, if so , tell me where i can learn more about it . Thanks ! 回答1: Use Realm Database for React Native , Realm is an object-oriented database. OO model makes it 10x faster than SQLite and saves you from running tons of query which is a common thing for a typical SQL database and fuse.js may help you to search text. 回答2: realm = new Realm({ schema: [StudentScheme] }) const mydata = realm

问题 I have a small problem in this case in my app I set default Portrait.But now this time i want show Portrait and landScape in Tabs not only Mobile phone .In mobile phones show only Portrait(Force Update to Portrait). I followed this link but I am getting this error and i dd't understand how can we create folders where can we place the data. I followed this link: but i didn't get Android: allow portrait and landscape for tablets, but force portrait on phone? 回答1: 1.Go to the Android folder

问题 When I use the -dontobfuscate option in my existing android app with a single React Native screen, release build works fine. (I had to also set react native configurations for pro-guard from https://github.com/facebook/react-native/blob/master/local-cli/generator-android/templates/src/app/proguard-rules.pro) However, I want to obfuscate my existing app and ignore react-native obfuscation only (since it's not supported as per : https://github.com/facebook/react-native/issues/7530) After

问题 I'm trying to run a project written in React Native and the app crashes: The solution stated on this thread is irrelevant since the enableProguardInReleaseBuilds variable is already configured to false. I've also had problems with RCT Video, solved with this thread so maybe it's related. Thanks in advance. 回答1: Solved after debugging in Android Studio. The error I had (java.lang.ClassCastException: android.app.Application cannot be cast to com.facebook.react.ReactApplication) was solved with

问题 I'm trying to run a project written in React Native and the app crashes: The solution stated on this thread is irrelevant since the enableProguardInReleaseBuilds variable is already configured to false. I've also had problems with RCT Video, solved with this thread so maybe it's related. Thanks in advance. 回答1: Solved after debugging in Android Studio. The error I had (java.lang.ClassCastException: android.app.Application cannot be cast to com.facebook.react.ReactApplication) was solved with