问题
I've created a new Android Studio Project and my MainActivity is a Navigation Drawer Activity.
So, I can't show up fragments. I've read many post on internet and here too.
Explaining:
I open navigation drawer, select menu "Podcast". PodcastsFragment should be shown, but it still showing activity.
MainActivity code:
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.util.Log;
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 com.google.android.gms.analytics.HitBuilders;
import com.google.android.gms.analytics.Tracker;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private Tracker mTracker;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// [START shared_tracker]
// Obtain the shared Tracker instance.
AnalyticsApplication application = (AnalyticsApplication) getApplication();
mTracker = application.getDefaultTracker();
// [END shared_tracker]
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.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
@Override
protected void onResume() {
Log.i("TESTE", "Setting screen name: " + "teste");
mTracker.setScreenName("Main " + "teste");
mTracker.send(new HitBuilders.ScreenViewBuilder().build());
super.onResume();
}
@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();
Fragment fragment = null;
FragmentTransaction ft = null;
if (id == R.id.nav_podcasts) {
Log.d("Clicked:", "nav_podcasts");
fragment = new PodcastsFragment();
} else if (id == R.id.nav_feed) {
//fragment = new FeedFragment();
Log.d("Clicked:", "nav_feed");
//fragment = new FeedFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
FeedFragment ff = new FeedFragment();
fragmentTransaction.add(R.id.container_body, ff);
fragmentTransaction.commit();
} else if (id == R.id.nav_downloads) {
//fragment = new DownloadsFragment();
Log.d("Clicked:", "nav_downloads");
} else if (id == R.id.nav_add) {
//fragment = new OPMLFragment();
Log.d("Clicked:", "nav_add");
} else if (id == R.id.nav_settings) {
//fragment = new SettingsFragment();
Log.d("Clicked:", "nav_settings");
}
if (fragment != null) {
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container_body, fragment).commit();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
PodcastsFragment code:
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class PodcastsFragment extends Fragment {
public PodcastsFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
//return inflater.inflate(R.layout.fragment_podcasts, container, false);
View rootView = inflater.inflate(R.layout.fragment_podcasts, container, false);
// Inflate the layout for this fragment
return rootView;
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
}
@Override
public void onDetach() {
super.onDetach();
}
}
app_bar_main code:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.test.test.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="@layout/content_main"/>
<!--<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="@dimen/fab_margin"
android:src="@android:drawable/ic_dialog_email" />-->
</android.support.design.widget.CoordinatorLayout>
activity_main code:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
layout="@layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.NavigationView
android:id="@+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="@layout/nav_header_main"
app:menu="@menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>
content_main code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:showIn="@layout/app_bar_main"
tools:context="com.test.test.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="teste"/>
<FrameLayout
android:id="@+id/container_body"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</RelativeLayout>
回答1:
Make the drawer's list in Your activity and add setOnItemClickListener().When the user selects an item in the drawer's list, the system calls onItemClick() on the OnItemClickListener given to setOnItemClickListener().
What you do in the onItemClick() method depends on how you've implemented your app structure. In the following example, selecting each item in the list inserts a different Fragment into the main content view (the FrameLayout element identified by the R.id.content_frame ID): for more delail please read these articles youtube and github example
回答2:
If you use Navigation Architecture Component, then you don't have to manually connect your fragments to your drawer MenuItem. The system will automatically tie you MenuItem to specific fragment If the id of the MenuItem in your menu/xyz_menu.xml matches the id of the destination in navigation/xyz_nav.xml, the NavController can then navigate to that destination.
Follow the correct steps mentioned in the official documentation : https://developer.android.com/guide/navigation/navigation-ui#Tie-navdrawer
Note :
They have a sample app linked to the same article which you can refer.
To get this is effect, do not implement
onNavigationItemSelectedotherwise it will override the system let you handle the navigation.
来源：https://stackoverflow.com/questions/37063475/navigation-drawer-doesnt-show-fragments