What are the basic topics needed for app development .I had learned the concepts of inheritence , virtual functions and polymorphism. Is template concept is needed ? Please give the list of all topics needed or oops concepts .
I have made a BMI calculator based on a tutorial from Youtube. I added a wallpaper to my app. I want to add a transparent frame to my background and all the controls would be put on that frame.
I tried this code:
The problem is that all the child nodes get affected by opacity and marigin settings.
I want to have opacity just in fram, not child nodes. Also, Child nodes must have their own padding.
How to fix this problem?
I'm new in Android programming and about to begin my classes on it. Before that, I had to install Android Studio on my PC. I downloaded Android Studio 4.1.3 for Windows 64-bit from developer.android.com. After successful installation and initial setup I launched it by selecting an Empty Activity Project Template. Once the IDE got ready with the default Hello World programme with its default code in MainActivity.java, I tried to run it with the default virtual device- Pixel_3a_API_30_x86. Now this is where the problem arises. Once the virtual device pops up, it's screen remains black and never fires up. I tried creating another virtual device in AVD manager and launch it from there, but of no avail, the problem still persists. As an alternative, I deleted all virtual devices from AVD manager, closed the project, re-opened it and created a virtual device anew. But again the same problem, the screen of the virtual device doesn't fire up and even the timeout for the app to connect the virtual device expires after sometime. I deleted the application and created a new one from the scratch and followed all the steps mentioned above, but with no effect. Assuming something wrong in the current release, I downloaded a previous release of Android Studio, i.e., Android Studio 4.1.1 for Windows 64-bit. But the problem still prevails in this one too. I spoke to a couple of Android programmers working on PCs running on Intel as well as AMD processors, but they never came across such a problem; everything is running fine on their PCs. I'm not even getting any error so that I can look into it. The only error being generated while creating a new virtual device in AVD manager for the first time, which says: "The ADB binary found at C:\Users\Admin\AppData\Local\Android\Sdk\platform-tools\adb.exe is obsolete and has serious performance problems with the Android Emulator. Please update to a newer version to get significantly faster app/file transfer." But as far I can see, I already have the updated version of the platform tools.
I tried all the options mentioned here and here, but none of them solved my problem. So I want to know why is Emulator not running on my PC and how can I make it work? Is it hardware problem? Do I need to update my processor, motherboard and RAM? Or is there some other issue I'm missing? I tried everything in my hand, but to no use. I'm absolutely new in Android and am not familiar with the settings and commands of the Android IDE. My classes are getting unreasonably delayed for this, because if the Emulator doesn't work, how will I run and test the codes and see how it actually works in a device. A whole month got wasted on this and I can't even write my first Hello World programme. Therefore I seek assistance from fellow Android programmers and experts to get me out of this deadlock anyhow. Please help.
Summary of my PC is given below:
OS Name: Microsoft Windows 10 Pro (64 bit OS)
OS Version: 10.0.19042 Build 19042.906
OS Experience: Windows Feature Experience Pack 120.2212.551.0
Once the virtual device pops up, it's screen remains black and never fires up.
How long are you waiting. At home, I used to have an Intel Core 2 Duo E7300 running at 2.66GHz with 4GB of RAM and it took over 2 minutes for my emulator to completely boot up. At work I had a slightly faster CPU and 8GB of RAM and it still took over a minute.
I tried creating another virtual device in AVD manager...
With what specs? The default is probably taxing your PC's RAM. On the two aforementioned PCs, I would scale the emulator specs down to the bare minimum.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
I'm waiting so long as the timeout for the app to connect the virtual device expires, for around fifteen minutes, but in vain.
With what specs?
While creating a virtual device in AVD manager, I tried with the default specs, i.e. Android 11 API level 30, 1536 MB RAM, 384 MB VM Heap, 800 MB Internal Storage, 512 MB SD Card memory (Studio-managed). It didn't work. Thereafter, I tried with Android 5.0 API level 21 and Android 5.1 API level 22, but to no effect. In terms of memory and storage settings, I increased specs more than the default settings with 2048 MB RAM, 2048 MB VM Heap, 2048 MB Internal Storage, 2048 MB SD Card memory (Studio-managed). Result is the same black screen. Next time, I scaled down the specs way below the default settings, i.e., 500 MB RAM, 250 MB VM Heap, 500 MB Internal Storage, 250 MB SD Card memory (Studio-managed). As usual, it yielded to nothing but the same black screen. Regarding Emulated Performance Graphics, I switched between Automatic, Hardware and Software, but of no avail.
I am not an expert but I learned somewhere that you can Install HAXM and Switch to x86. Using an x86 system image can speed up the emulator. Creating an x86 AVD is simple. All you need to do is when you’re creating a new AVD, simply select the ‘x86 Images’ tab in the ‘System Image’ window.
HAXM is needed in a machine that runs on an Intel processor. Mine is an AMD Phenom processor for which you need to install Android Emulator Hypervisor Driver for AMD Processors, which is the equivalent of HAXM on AMD machines. However, for diagnosis, I already installed HAXM which can be seen in the screenshot of the SDK tools of my SDK Manager here. But that didn't yield to anything.
Regarding using x86 system image, that's what I tried multiple times but with no effect. While creating a virtual device, I tried selecting the default x86 image [Release Name: R, API Level: 30, ABI: x86, Target: Android 11.0 (Google APIs)] that is available in the "Recommended" tab of the System Image window. That produced no effect other than the black emulator screen. Assuming the emulator and image specs to be too high for my RAM/PC, I scaled it down by using the following two images from the "x86 Images" tab of the System Image window as you mentioned:
1. Release Name: Lollipop, API Level: 22, ABI: x86, Target: Android 5.1
2. Release Name: Lollipop, API Level: 21, ABI: x86, Target: Android 5.0
Both yielded the same black dead emulator screen.
I tried using other non-x86 arm and armeabi images, but to no avail. None could produce any activity on the emulator screen.
As more reading on the topic brought forward, I guess, in case of AMD processors, emulator is supported only by the Ryzen series and above. Any processor below it won't work. Android emulators are developed keeping in mind Intel processors primarily. So, I believe, the only safe bet to get rid of this problem and be future-proof is to update my hardware (processor, motherboard, RAM), specifically with a contemporary Intel processor. I don't see any other solution as of now. Although, any better advice is always welcome!