Example
Up navigation is done in android by adding android:parentActivityName="" in Manifest.xml to the activity tag. Basically with this tag you tell the system about the parent activity of a activity.
How is it done?
<uses-permission android:name="android.permission.INTERNET" />
<application
android:name=".SkillSchoolApplication"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".ui.activities.SplashActivity"
android:theme="@style/SplashTheme">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".ui.activities.MainActivity" />
<activity android:name=".ui.activities.HomeActivity"
android:parentActivityName=".ui.activities.MainActivity/> // HERE I JUST TOLD THE SYSTEM THAT MainActivity is the parent of HomeActivity
</application>
Now when i will click on the arrow inside the toolbar of HomeActivity it will take me back to the parent activity.
Java Code
Here i will write the appropriate java code required for this functionality.
public class HomeActivity extends AppCompatActivity {
@BindView(R.id.toolbar)
Toolbar toolbar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
ButterKnife.bind(this);
//Since i am using custom tool bar i am setting refernce of that toolbar to Actionbar. If you are not using custom then you can simple leave this and move to next line
setSupportActionBar(toolbar);
getSupportActionBar.setDisplayHomeAsUpEnabled(true); // this will show the back arrow in the tool bar.
}
}
If you run this code you will see when you press back button it will take you back to MainActivity. For futher understanding of Up Navigation i would recommend reading docs
You can more customize this behaviour upon your needs by overriding
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
// Respond to the action bar's Up/Home button
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this); // Here you will write your logic for handling up navigation
return true;
}
return super.onOptionsItemSelected(item);
}
Simple Hack
This is simple hack which is mostly used to navigate to parent activity if parent is in backstack. By calling onBackPressed() if id is equal to android.R.id.home
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
switch (id) {
case android.R.id.home:
onBackPressed();
return true;
}
return super.onOptionsItemSelected(item);
}
