You can force Android to hide the virtual keyboard using the InputMethodManager, calling hideSoftInputFromWindow, passing in the token of the window containing your focused view.
// Check if no view has focus:
View view = this.getCurrentFocus();
if (view != null) {
InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}
This will force the keyboard to be hidden in all situations. In some cases, you will want to pass in InputMethodManager.HIDE_IMPLICIT_ONLY as the second parameter to ensure you only hide the keyboard when the user didn't explicitly force it to appear (by holding down the menu).
Note: If you want to do this in Kotlin, use:
context?.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
Kotlin Syntax
// Only runs if there is a view that is currently focused
this.currentFocus?.let { view ->
val imm = getSystemService(Context.INPUT_METHOD_SERVICE) as? InputMethodManager
imm?.hideSoftInputFromWindow(view.windowToken, 0)
}
Inserts, updates, deletes and reads are generally OK from multiple threads, but Brad's answer is not correct. You have to be careful with how you create your connections and use them. There are situations where your update calls will fail, even if your database doesn't get corrupted.
The basic answer.
The SqliteOpenHelper object holds on to one database connection. It appears to offer you a read and write connection, but it really doesn't. Call the read-only, and you'll get the write database connection regardless.
So, one helper instance, one db connection. Even if you use it from multiple threads, one connection at a time. The SqliteDatabase object uses java locks to keep access serialized. So, if 100 threads have one db instance, calls to the actual on-disk database are serialized.
So, one helper, one db connection, which is serialized in java code. One thread, 1000 threads, if you use one helper instance shared between them, all of your db access code is serial. And life is good (ish).
If you try to write to the database from actual distinct connections at the same time, one will fail. It will not wait till the first is done and then write. It will simply not write your change. Worse, if you don’t call the right version of insert/update on the SQLiteDatabase, you won’t get an exception. You’ll just get a message in your LogCat, and that will be it.
So, multiple threads? Use one helper. Period. If you KNOW only one thread will be writing, you MAY be able to use multiple connections, and your reads will be faster, but buyer beware. I haven't tested that much.
Here's a blog post with far more detail and an example app.
Gray and I are actually wrapping up an ORM tool, based off of his Ormlite, that works natively with Android database implementations, and follows the safe creation/calling structure I describe in the blog post. That should be out very soon. Take a look.
In the meantime, there is a follow up blog post:
Also checkout the fork by 2point0 of the previously mentioned locking example:
Best Answer
From Lollipop (API 21) onwards, Android defines the VectorDrawable class, for defining drawables based on vector graphics. Android Studio 1.4 adds the "Vector Asset Studio" to make them easier to work with, including an SVG import feature and a new Gradle plugin that generates PNG versions of VectorDrawable icons at build time for API 20 and earlier. There's also a third-party tool for converting SVGs to VectorDrawables. Bear in mind that although vector drawables can be defined in XML, the file format is not SVG and not all SVG files can be successfully converted. Simple graphics like icons should work OK.
If you still need to generate PNGs yourself, you'll need to generate your icons at various resolutions. For ease of generating those PNGs I design icons as SVG and then export to the various sizes using Inkscape which is free and cross-platform. It's got some nice features for designing icons, including the Icon Preview view (see below), and it generates nice crisp PNGs.