background

问题 I'd like to create a a new stateless widget class that is defined by 2 images(top, bottom) and a line(defined by a function, e.g. (x){x+500} , a width(can be 0, if it shouldn't be drawn), and a color) separating the two images. For each pixel: If the y position of a pixel is greater than the result of f(x) + width/2 a pixel of bottom shall be drawn If it's smaller than f(x) - width / 2 a pixel of top shall be drawn Else a pixel of the given line color shall be drawn Blow see an example of

问题 How do I use an image as the background for a ggplot2 plot? For example, the code: mtcars %>% ggplot(aes(cyl)) + geom_bar() + theme(plot.background = element_rect(fill = "black")) It results in the following: and the background color is black. How can I choose an image to be the background, and not only choose its color? 回答1: you can plot one on top of the other, library(ggplot2) p <- ggplot(mtcars, aes(cyl)) + geom_bar() + theme(plot.background = element_rect(fill=NA)) library(grid) grid

问题 I'm using flutter_beacon for detecting iBeacons in one of my flutter project. Its working fine in foreground and in background for android version below 8. But its not detecting beacons in background for android version 8 and above. As per background location limits: Android 8.0 (API level 26) limits how frequently background apps can retrieve the user's current location. Apps can receive location updates only a few times each hour. I've also reported an issue to github with the example code

问题 Hi all i want to run a java application as backend process.that is like tomcat server.For that i had developed one application.and made one class as main class and calling from one script file .i.e(startup.sh) file.in startup.sh file i was calling one class.that is MainMethodClass.In main method class i had written my business logic.when i am running this app in linux server from using putty is is working until putty window is not closed.As closed after putty window it is also stopped.but i

问题 I am working with other contributors on an open-source project in which we have made an Android App. Whenever the app is opened we get a notification that the app is running in the background and even when the app session is terminated, the notification doesn't go away. Here is the link for the project The app has a lot of classes which could be the reason but we are not able to narrow it down. Though we do think that it could be the BluetoothService activity which uses Bluetooth signals. The

问题 Location updates correctly when app is in foreground or when sent to background while user is moving but if app goes into stationary region while app is closed or is background location stops to update. Even if I travel distance once app goes to stationary region from background or terminate state it does not exit stationary region and stops updating location on server. Environment: React Native version: 0.59.9 Plugin version: 0.6.3 Platform: Android OS version: 7 Device manufacturer and

问题 Location updates correctly when app is in foreground or when sent to background while user is moving but if app goes into stationary region while app is closed or is background location stops to update. Even if I travel distance once app goes to stationary region from background or terminate state it does not exit stationary region and stops updating location on server. Environment: React Native version: 0.59.9 Plugin version: 0.6.3 Platform: Android OS version: 7 Device manufacturer and

问题 I am using the new iOS13 background task framework, with the implementation of a BGAppRefreshTask type. My problem is, my device is never calling the task, even after waiting several hours, but I am able to successfully run the code using the Debugger trick of calling _simulateLaunchForTaskWithIdentifier. I have setup the following: Enabled my app with the Background Modes capability, a checking the "Background fetch". Added my background Id to Info.plist under "Permitted background task

问题 How to change the background color of the floating hint in a text input layout outline box style to transparent. I think the attached picture clearly states the issue It should be red above the stroke and white below). What I did to change the background itself was: <style name="App.TextInputLayout" parent="Widget.MaterialComponents.TextInputLayout.OutlinedBox.Dense"> <item name="boxBackgroundColor">@color/white</item> </style> Any help is greatly appreciated 回答1: If you look at the style

问题 I have this HTML <html> <head> </head> <body bgcolor="#FFFFFF" style="margin:0px;padding:0px;" <div style=width:100%;color:#000000;padding:25px;font-family: Segoe UI;font-size: 17px;"></div></body></html> Here i have set bgcolor="#FFFFFF" but i want it to be transparent how to do it ? 回答1: HTML provides no means to specify a transparent background (and the means it has to specify backgrounds of any kind are obsolete and should not be used). You can do this in CSS. body { background-color: