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
Update: Latest ActionBar (Title) pattern:
FYI, ActionBar was introduced in API Level 11. ActionBar is a window feature at the top of the Activity that may display the activity title, navigation modes, and other interactive items like search.
I exactly remember about customizing title bar and making it consistent through the application. So I can make a comparison with the earlier days and can list some of the advantages of using ActionBar:
For example:
=> Normal way,
=> Customizing Action Bar,
For example:
Styling the Action Bar:
The ActionBar provides you with basic and familiar looks, navigation modes and other quick actions to perform. But that doesn't mean it looks the same in every app. You can customize it as per your UI and design requirements. You just have to define and write styles and themes.
Read more at: Styling the Action Bar
And if you want to generate styles for ActionBar then this Style Generator tool can help you out.
=================================================================================
Old: Earlier days:
=> Normal way,
you can Change the Title of each screen (i.e. Activity) by setting their
Android:label
=> Custom - Title - bar
But if you want to Customize title-bar in your own way, i.e.
Want to put Image icon and custom-text
, then the following code works for me:main.xml
titlebar.xml
TitleBar.java
strings.xml
The strings.xml file is defined under the
values
folder.