How To Set Back Button In Android

How to Add and Customize Dorsum Push button of Action Bar in Android?

The action bar (sometimes referred to as the app bar), if information technology exists for an activity, will be at the top of the activity'south content area, typically directly underneath the condition bar. Information technology is a carte bar that runs across the acme of the activity screen in android. Android ActionBar can contain menu items that become visible when the user clicks the "menu" button. In general, an ActionBar composed of the following four components:

App Icon: App branding logo or icon will be shown here
View Control: A dedicated infinite to brandish the Application championship. Also provides the option to switch between views by adding spinner or tabbed navigation
Activity Buttons: Major deportment of the app could be added here
Activeness Overflow: All unimportant action volition be displayed every bit a menu

Below is a sample image to testify where the Activeness Bar/Toolbar/App Bar is nowadays on an android device.

Action Bar/Toolbar/App Bar

The action bar is a primary toolbar within an activity that tin can be used to display an activity title and other interactive items. Ane of the nearly used items is a Back Navigation Button. The back push is used to move backward from the previously visited screen by the user. Well-nigh Android devices have a dedicated back button all the same a back button on the action bar enhances the user feel.

Add Back Button in Activeness Bar

To create a new project in Android Studio please refer to How to Create/Start a New Projection in Android Studio. At that place is no demand to alter anything in the activity_main.xml file. The simply file we have to piece of work with is Working with the MainActivity file.

Create action bar variable and call function getSupportActionBar() in the java/kotlin file.
Evidence back button using actionBar.setDisplayHomeAsUpEnabled(true) this will enable the back button.
Custom the back effect at onOptionsItemSelected. This will enable the back office to the button on the press. Encounter the below lawmaking for reference. We have provided both the java and kotlin code for MainActivity.

Java

                import                android.os.Package;              
                import                android.view.MenuItem;              
                import                androidx.annotation.NonNull;              
                import                androidx.appcompat.app.ActionBar;              
                import                androidx.appcompat.app.AppCompatActivity;              
                public                grade                MainActivity                                extends                AppCompatActivity {              
                                @Override              
                                protected                void                onCreate(Parcel savedInstanceState) {              
                                super                .onCreate(savedInstanceState);              
                                setContentView(R.layout.activity_main);              
                                ActionBar actionBar = getSupportActionBar();              
                                actionBar.setDisplayHomeAsUpEnabled(                true                );              
                                }              
                                @Override              
                                public                boolean                onOptionsItemSelected(                @NonNull                MenuItem item) {              
                                switch                (item.getItemId()) {              
                                instance                android.R.id.dwelling house:              
                                this                .finish();              
                                return                true                ;              
                                }              
                                return                super                .onOptionsItemSelected(item);              
                                }              
                }              

Kotlin

                import                android.os.Bundle              
                import                android.view.MenuItem              
                import                androidx.appcompat.app.AppCompatActivity              
                class                MainActivity : AppCompatActivity() {              
                                override fun onCreate(savedInstanceState: Packet?) {              
                                super                .onCreate(savedInstanceState)              
                                setContentView(R.layout.activity_main)              
                                var actionBar = getSupportActionBar()              
                                if                (actionBar !=                                null                ) {              
                                actionBar.setDisplayHomeAsUpEnabled(                true                )              
                                }              
                                }              
                                override fun onContextItemSelected(particular: MenuItem): Boolean {              
                                when (particular.itemId) {              
                                android.R.id.dwelling -> {              
                                stop()              
                                return                truthful              
                                }              
                                }              
                                render                super                .onContextItemSelected(item)              
                                }              
                }              

Output:

Customize Back Push button in Action Bar

Nosotros can hands Customize the Back Button by using the getSupportActionBar() library and setting the drawable file using setHomeAsUpIndicator in the java/kotlin file.

// Customize the dorsum push button

actionBar.setHomeAsUpIndicator(R.drawable.mybutton);

The complete code is given below.

Coffee

                import                android.os.Bundle;              
                import                android.view.MenuItem;              
                import                androidx.annotation.NonNull;              
                import                androidx.appcompat.app.ActionBar;              
                import                androidx.appcompat.app.AppCompatActivity;              
                public                class                MainActivity                                extends                AppCompatActivity {              
                                @Override              
                                protected                void                onCreate(Packet savedInstanceState) {              
                                super                .onCreate(savedInstanceState);              
                                setContentView(R.layout.activity_main);              
                                ActionBar actionBar = getSupportActionBar();              
                                actionBar.setHomeAsUpIndicator(R.drawable.mybutton);              
                                actionBar.setDisplayHomeAsUpEnabled(                true                );              
                                }              
                                @Override              
                                public                boolean                onOptionsItemSelected(                @NonNull                MenuItem particular) {              
                                switch                (item.getItemId()) {              
                                case                android.R.id.home:              
                                this                .finish();              
                                return                true                ;              
                                }              
                                return                super                .onOptionsItemSelected(item);              
                                }              
                }              

Kotlin

                import                android.os.Bundle              
                import                android.view.MenuItem              
                import                androidx.appcompat.app.AppCompatActivity              
                class                MainActivity : AppCompatActivity() {              
                                override fun onCreate(savedInstanceState: Bundle?) {              
                                super                .onCreate(savedInstanceState)              
                                setContentView(R.layout.activity_main)              
                                var actionBar = getSupportActionBar()              
                                if                (actionBar !=                                null                ) {              
                                actionBar.setHomeAsUpIndicator(R.drawable.mybutton);              
                                actionBar.setDisplayHomeAsUpEnabled(                true                );              
                                }              
                                }              
                                override fun onContextItemSelected(item: MenuItem): Boolean {              
                                when (particular.itemId) {              
                                android.R.id.dwelling -> {              
                                cease()              
                                render                true              
                                }              
                                }              
                                render                super                .onContextItemSelected(particular)              
                                }              
                }              

Output: