We Keep Coding

Android Studio Navigation Drawer item opening website

I used the basic "Navigation Drawer Acticity" in Anroid Studio when creating the new project. The fragments work well and I've managed to add new fragments and everything.
However, items in the drawer menu that direct you to a certain website don't work. I've tried different methods with public boolean onNavigationItemSelected(MenuItem item){} and nothing happens when I press the items.
It looks like this:
#Override
public boolean onNavigationItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.nav_moodle) {
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com"));
startActivity(browserIntent);
return true;
}
return true;
}
As you can see I did nothing for the fragments to work since they work fine already but when I press the button "moodle", nothing happens.
What have I done wrong?

Here is my MainActivity:
package com.example.ustudy;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.view.Menu;
import android.widget.Toast;
import com.example.ustudy.ui.home.HomeFragment;
import com.google.android.material.snackbar.Snackbar;
import com.google.android.material.navigation.NavigationView;
import androidx.annotation.NonNull;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.AppCompatActivity;
import com.example.ustudy.databinding.ActivityMainBinding;
import org.jetbrains.annotations.NotNull;
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener{
private AppBarConfiguration mAppBarConfiguration;
private ActivityMainBinding binding;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
//required for the top bar to be clickable
setSupportActionBar(binding.appBarMain.toolbar);
//button in the bottom right corner
binding.appBarMain.fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = binding.drawerLayout;
//Navigationview for the drawer (implemented in "activity_main.xml")
NavigationView navigationView = binding.navView;
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
//each screen mentioned in the columns below (R.id.xy) will show the hamburger menu in the top left corner
//on screens, not included in the columns, there will be a "back arrow" instead of the ham. menu
mAppBarConfiguration = new AppBarConfiguration.Builder(
R.id.nav_home, R.id.nav_nachricht, R.id.nav_lerngruppe, R.id.nav_lehrveranstaltung)
.setDrawerLayout(drawer)
.build();
//controls what happens when one of the items in the hamburger menu is clicked on
//go to "mobile_navigation.xml" to add screens to go to
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
//required to set up the hamburger menu icon and the back-arrow icon on the top bar(without it
//the user had to slide the side of the screen to open the menu)
NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
//enables the items in the hamburger menu to go to a certain screen after clicking on them
NavigationUI.setupWithNavController(navigationView, navController);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu (three dots on the right); this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onSupportNavigateUp() {
//enables the usage of the back-arrow on every screen
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
return NavigationUI.navigateUp(navController, mAppBarConfiguration)
|| super.onSupportNavigateUp();
}
#Override
public boolean onNavigationItemSelected(#NonNull #NotNull MenuItem item) {
int id = item.getItemId();
if (id == R.id.nav_moodle) {
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com"));
startActivity(browserIntent);
return true;
}
return true;
}
}
Please, let me know if you need more!

Having trouble with onNavigationItemSelected and beginTransaction()

I am creating a small app that will allow the user to view different categories of books for college.
So far in the activity main drawer I have a few different categories that should load a layout with a listView and populate this list from an arrayAdapter when selected. I have it set up and semi-working on one of my layouts, but the problem arises when I change to a different category from the navigation drawer, the listView is still displayed on the screen and I can't seem to figure out how to get it to stop.
I thought that I would need to use endTransaction() but I'm not really sure yet if I'm using the right thing.
I am a beginner to Java and Android Studio, so I hope that I am making sense in what I am asking.
If more code or information is needed, I will be happy to provide.
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.view.View;
import android.support.design.widget.NavigationView;
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.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.view.ViewGroup;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.Fragment;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
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);
FragmentManager fm = getSupportFragmentManager();
fm.beginTransaction().replace(R.id.content_frame, new MainFragment()).commit();
//loads the home screen when app launches
displaySelectedScreen(R.id.nav_home);
}
#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);
}
private void displaySelectedScreen(int id) {
Fragment fragment = null;
//loads each layout inflator depending on what menu item has been clicked
switch(id) {
case R.id.nav_home:
fragment = new Home();
break;
case R.id.nav_book:
fragment = new All();
break;
case R.id.nav_sci_fi:
fragment = new SciFi();
break;
case R.id.nav_fantasy:
fragment = new Fantasy();
break;
case R.id.nav_dystopian:
fragment = new Dystopian();
break;
case R.id.nav_about:
fragment = new About();
break;
case R.id.nav_contact:
fragment = new ContactUs();
break;
}
if(fragment != null) {
FragmentTransaction ft = getSupportFragmentManager(). beginTransaction();
ft.replace(R.id.content_main, fragment);
ft.commit();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
FragmentManager fm=getSupportFragmentManager();
int id = item.getItemId();
if (id == R.id.nav_book) {
// Handle the camera action
} else if (id == R.id.nav_sci_fi) {
fm .beginTransaction().replace(R.id.content_frame, new BookFragment()).commit(); setTitle("Sci-Fi");
//TODO: endTransaction
} else if (id == R.id.nav_fantasy) {
} else if (id == R.id.nav_dystopian) {
} else if (id == R.id.nav_about) {
}
displaySelectedScreen(id);
return true;
}
}

Your displaySelectedScreen() function is using a FragmentTransaction instead of FragmentManager. Try using FragmentManager.

My program crashes and I don't know why

I'm learning how to program in Java for Android and my program keeps crashing. It's suppoesed to convert from Celsius to Fahrenheit.
package com.example.myapplication;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
import android.widget.RadioGroup.OnCheckedChangeListener;
public class MainActivity extends Activity implements RadioGroup.OnCheckedChangeListener
{
public static final int MY_CODE=2;
EditText temp;
RadioButton converttoF,converttoC,selectedtype;
RadioGroup conversion;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
conversion = (RadioGroup)findViewById(R.id.conversion);
conversion.setOnCheckedChangeListener(this);
converttoF = (RadioButton)findViewById(R.id.converttoF);
converttoC = (RadioButton)findViewById(R.id.converttoC);
}
#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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onCheckedChanged(RadioGroup group, int checkedId)
{
selectedtype = (RadioButton) findViewById(checkedId);
Intent i = new Intent(this, Activity4Result.class);
i.putExtra("temper", temp.getText().toString());
if(selectedtype.equals(converttoC))
{
Toast.makeText(this,"C chosen", Toast.LENGTH_SHORT).show();
i.putExtra("type", 'c');
startActivityForResult(i, MY_CODE);
}
else
{
Toast.makeText(this,"F chosen", Toast.LENGTH_SHORT).show();
i.putExtra("type", 'f');
startActivityForResult(i, MY_CODE);
}
}
}
My guess is that the problem is happening in the "onCheckedChanged", because it crashes when I push any RadioButton.

I assume (It would be better if you post the crash log along with your question, so that we can help you better and stop assuming) you are getting a null pointer exception on the following code:
i.putExtra("temper", temp.getText().toString());
In your code you declared temp, but it is never initialised. You need to initialise temp before using it.

ERROR: Not able to resolve navigation_drawer_open in Android Studio

I am trying to build a Translucent Navigation bar for my android app. I separately tried developing the task bar and then had intend to include it in my application.
I am not allowed to upload images yet (as I don't have the reputation), therefore here's an example of what I am trying to build for my APP:
Image Slider example
I am getting errors in the MainActivity.java file.
I get an Error in the following line of code :
mDrawerToggle = new ActionBarDrawerToggle(this,Drawer,toolbar,R.string.navigation_drawer_open, R.string.navigation_drawer_close)
Error :
Error:(48, 79) error: cannot find symbol variable navigation_drawer_open
Error:(48, 112) error: cannot find symbol variable navigation_drawer_close
This is the entire code of MainActivity.java file:
package sha.testing_sidebar;
import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
public class MainActivity extends ActionBarActivity {
String TITLES [] = {"Home","Events","Mail","Blog","Attending"};
int ICONS [] = {R.drawable.ic_home,R.drawable.ericsson_2_png,R.drawable.ic_mqil_hdpi,R.drawable.ic_blog_2,R.drawable.ic_attending};
String NAME = "Sharang Bharadwaj";
String EMAIL = "sha.bh91#gmail.com";
int PROFILE = R.drawable.sha1;
private Toolbar toolbar;
RecyclerView mRecyclerView;
RecyclerView.Adapter mAdapter;
RecyclerView.LayoutManager mLayoutManager;
DrawerLayout Drawer;
ActionBarDrawerToggle mDrawerToggle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.tool_bar);
setSupportActionBar(toolbar);
mRecyclerView = (RecyclerView) findViewById(R.id.RecyclerView);
mRecyclerView.setHasFixedSize(true);
mAdapter = new sha.testing_sidebar.MyAdapter(TITLES,ICONS,NAME,EMAIL,PROFILE);
mRecyclerView.setAdapter(mAdapter);
mLayoutManager = new LinearLayoutManager(this);
Drawer = (DrawerLayout) findViewById(R.id.DrawerLayout);
mDrawerToggle = new ActionBarDrawerToggle(this,Drawer,toolbar,R.string.navigation_drawer_open, R.string.navigation_drawer_close) {
#Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
//actions upon opening slider
//presently nothing
}
#Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
//actions upon closing slider
//presently nothing
}
};
//Drawer Toggle Object made
Drawer.setDrawerListener(mDrawerToggle);
mDrawerToggle.syncState();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.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);
}
}
The error is

Add the following in your strings.xml file
<string name="navigation_drawer_open">Drawer Open</string>
<string name="navigation_drawer_close">Drawer Closed</string>
It should work after that.

Just copy/paste this in the strings file
<string name="navigation_drawer_open">Drawer Open</string>
<string name="navigation_drawer_close">Drawer Closed</string>
they might be there already, if true, both will be underlined in red.
if so erase the existing ones and copy/paste the same two lines.

Onclick imagebutton-action (menu)

I'm making an app and when it launches it starts Mainactivity.java
Mainactivity.java opens a layout with 9 Imagebuttons.
How can I implement in my code in Mainactivity.java that once one is clicked it opens another activity (like telefoonnummers.java)?
Sorry for my bad English but I'm dutch and a non-native speaker.
I have this code in Mainactivity.java:
package com.example.rome;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.EditText;
import android.widget.Button;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
Very clean as you see, but how can I add the implementation, would you guys please help???
My Imagebuttons are all just called imagebutton1, imagebuttton2 etc. btw.

After
setContentView(R.layout.activity_main);
add for each ImageButton:
findViewById(R.id.imagebutton1).setOnClickListener(this);
Make class implement OnClickListener
class MainActivity extends Activity implements View.OnClickListener {
and add this method:
#Override
public void onClick(View v){
switch(v.getId()){
case R.id.R.id.imagebutton1:
startActivity(new Intent(telefoonnummers.class));
break;
case R.id.R.id.imagebutton2:
startActivity(new Intent(telefoonnummers.class));
break;
//-- more cases --
}
}