Grace Tanya Grace Tanya - 1 year ago 76
Android Question

How to switch between fragments using button under navigation activity

I'm just new on Android Studio so please bear with me. I created two fragments named locate_before and locate_after. I have a button with an id of trigger on my locate_before fragment. I want to switch to locate_after after clicking that button.

Here's my main activity. I used a frame container for my fragments. I already created a code for what I want named onSelectFragment but it does not work. It says "method onSelectFragment is never used"

import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {

Button trigger;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

//Set the fragment initially
locate_before fragment = new locate_before();
android.support.v4.app.FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.commit();

FragmentManager fm = getSupportFragmentManager();
FragmentTransaction transaction = fm.beginTransaction(); //check this out

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();

NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);

}

public void onSelectFragment(View v){
Fragment newFragment;

if(v == findViewById(R.id.trigger)){
newFragment = new locate_after();
}
else{
newFragment = new locate_before();
}

FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, newFragment);
transaction.addToBackStack(null);
transaction.commit();
}



@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}

return super.onOptionsItemSelected(item);
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();

if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {

} else if (id == R.id.nav_slideshow) {

} else if (id == R.id.nav_manage) {

} else if (id == R.id.nav_share) {

} else if (id == R.id.nav_send) {

}

DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}

}


locate_before fragment java that ofc extends Fragment

public locate_before () {
// Required empty public constructor

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_locate_before, container, false);

// Inflate the layout for this fragment
return rootView;
}
}


locate_before xml file button

<Button
android:id="@+id/trigger"
android:layout_width="284dp"
android:layout_height="58dp"
android:text="View Car's Location"
android:layout_marginRight="24dp"
app:layout_constraintRight_toRightOf="parent"
android:layout_marginLeft="8dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintHorizontal_bias="0.633"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="133dp" />


locate_after java

public class locate_after extends Fragment {


public locate_after () {
// Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_locate_after, container, false);

// Inflate the layout for this fragment
return rootView;
}
}


Thank you!

Answer Source

Your buttom seems to have no onClickListener.

Add android:onClick="onSelectFragment" in your XML or bind your Button and add an onClickListener in your OnCreate.

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