You need to override onSaveInstanceState(Bundle savedInstanceState)
and write the application state values you want to change to the Bundle
parameter like this:
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
super.onSaveInstanceState(savedInstanceState);
// Save UI state changes to the savedInstanceState.
// This bundle will be passed to onCreate if the process is
// killed and restarted.
savedInstanceState.putBoolean("MyBoolean", true);
savedInstanceState.putDouble("myDouble", 1.9);
savedInstanceState.putInt("MyInt", 1);
savedInstanceState.putString("MyString", "Welcome back to Android");
// etc.
}
The Bundle is essentially a way of storing a NVP ("Name-Value Pair") map, and it will get passed in to onCreate()
and also onRestoreInstanceState()
where you would then extract the values from activity like this:
@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
// Restore UI state from the savedInstanceState.
// This bundle has also been passed to onCreate.
boolean myBoolean = savedInstanceState.getBoolean("MyBoolean");
double myDouble = savedInstanceState.getDouble("myDouble");
int myInt = savedInstanceState.getInt("MyInt");
String myString = savedInstanceState.getString("MyString");
}
Or from a fragment.
@Override
public void onViewStateRestored(@Nullable Bundle savedInstanceState) {
super.onViewStateRestored(savedInstanceState);
// Restore UI state from the savedInstanceState.
// This bundle has also been passed to onCreate.
boolean myBoolean = savedInstanceState.getBoolean("MyBoolean");
double myDouble = savedInstanceState.getDouble("myDouble");
int myInt = savedInstanceState.getInt("MyInt");
String myString = savedInstanceState.getString("MyString");
}
You would usually use this technique to store instance values for your application (selections, unsaved text, etc.).
I'm assuming you're using XML layout.
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="@string/**yourtextstring**"
/>
You can also use gravity center_vertical
or center_horizontal
according to your need.
and as @stealthcopter commented
in java: .setGravity(Gravity.CENTER);
Best Answer
The simplest, and best long-term solution, is to use
BuildConfig.DEBUG
. This is aboolean
value that will betrue
for a debug build,false
otherwise:There have been reports that this value is not 100% reliable from Eclipse-based builds, though I personally have not encountered a problem, so I cannot say how much of an issue it really is.
If you are using Android Studio, or if you are using Gradle from the command line, you can add your own stuff to
BuildConfig
or otherwise tweak thedebug
andrelease
build types to help distinguish these situations at runtime.The solution from Illegal Argument is based on the value of the
android:debuggable
flag in the manifest. If that is how you wish to distinguish a "debug" build from a "release" build, then by definition, that's the best solution. However, bear in mind that going forward, thedebuggable
flag is really an independent concept from what Gradle/Android Studio consider a "debug" build to be. Any build type can elect to set thedebuggable
flag to whatever value that makes sense for that developer and for that build type.