Настройка фрагмента «On start»

Question

Я хочу установить определенный фрагмент для начала при открытии моего приложения. Существует встроенный макет под названием «content_home», который я не знаю, как удалить, и я думаю, что это тот, который был открыт при запуске.

Теперь, когда я открываю приложение, я вижу пустой экран, затем открываю ящик и нажимаю «Домой», который я хочу открыть по умолчанию, не вызывая его.

HomeActivity.java

import android.app.Fragment; 
 
import android.app.FragmentManager; 
 
import android.content.Intent; 
 
import android.os.Bundle; 
 
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.TextView; 
 

 
public class HomeActivity extends AppCompatActivity 
 
     implements NavigationView.OnNavigationItemSelectedListener { 
 

 
    private NavigationView navigationView; 
 
    private DrawerLayout drawer; 
 
    private TextView tvFullName, tvEmail; 
 
    private Fragment fragment = null; 
 
    FragmentManager fragmentManager; 
 

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

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

 
     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 Toggle: 
 
     drawer.setDrawerListener(toggle); 
 
     toggle.syncState(); 
 

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

 
    @Override 
 
    public void onBackPressed() { 
 
     if (drawer.isDrawerOpen(GravityCompat.START)) { 
 
      drawer.closeDrawer(GravityCompat.START); 
 
     } else { 
 
      super.onBackPressed(); 
 
     } 
 
    } 
 

 
    @Override 
 
    public boolean onCreateOptionsMenu(Menu menu) { 
 
     getMenuInflater().inflate(R.menu.home, menu); 
 
     return true; 
 
    } 
 

 
    @Override 
 
    public boolean onOptionsItemSelected(MenuItem item) { 
 

 
     int id = item.getItemId(); 
 
     if (id == R.id.action_search) { 
 
      return true; 
 
     } 
 

 
     return super.onOptionsItemSelected(item); 
 
    } 
 

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

 
     switch (item.getItemId()) { 
 
      case R.id.nav_home: 
 
       fragment = new HomeFragment(); 
 
       break; 
 
      case R.id.nav_settings: 
 
       fragment = new SettingsFragment(); 
 
       setNavUserDetails(); 
 
       break; 
 
     } 
 
     fragmentManager = getFragmentManager(); 
 
     if (fragment != null) 
 
      fragmentManager.beginTransaction().replace(R.id.content_home, fragment).commit(); 
 
     drawer.closeDrawer(GravityCompat.START); 
 
     return true; 
 
    } 
 

 
}

activity_home.xml:

<?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_home" 
 
     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_home" 
 
     app:menu="@menu/logged_out_drawer_menu" /> 
 
</android.support.v4.widget.DrawerLayout>

app_bar_home.xml:

<?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.example.amit.java5776_7546_8412.HomeActivity"> 
 

 
    <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_home" />   // <!-- THIS ONE --> 
 

 
</android.support.design.widget.CoordinatorLayout>

content_home.xml это почти пустой RelativeLayout ... Я не вижу причин, чтобы вставить его тоже ...

Answer 1

добавить следующий код в вашей деятельности OnCreate

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

    // add the home content when just opening the app 
    if(savedInstanceState == null) { 
     getFragmentManager() 
      .beginTransaction() 
      .replace(R.id.content_home, new HomeFragment()) 
      .commit(); 
    } 

Answer 2

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

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

    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 Toggle: 
    drawer.setDrawerListener(toggle); 
    toggle.syncState(); 

    navigationView = (NavigationView) findViewById(R.id.nav_view); 
    navigationView.setNavigationItemSelectedListener(this); 
    //checked the home as default when the app created 
    navigationView.setCheckedItem(R.id.nav_home); 
}