Android更好地實現導航片段

Question

我有一個導航視圖和繪製我的應用程序的佈局，我使用片段之間切換視圖。我現在有它實現這樣的，它工作正常：

app_bar_main.xml：

<LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:orientation="vertical"> 

     <android.support.design.widget.AppBarLayout 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      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> 

     <FrameLayout 
      android:id="@+id/fragment_container" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent"></FrameLayout> 
    </LinearLayout> 

我設置的初始片段時，在我的MainActivity類的onCreate應用程序第一次啓動：

public class MainActivity extends AppCompatActivity 
     implements NavigationView.OnNavigationItemSelectedListener { 

    //Provide global access to navigationview and toolbar 
    NavigationView navigationView = null; 
    Toolbar toolbar = null; 

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

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

當用戶選擇一個菜單項時，我設置了這樣的換出片段：

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

     if (id == R.id.nav_new) { 
      NewFragment fragment = new NewFragment(); 
      android.support.v4.app.FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
      fragmentTransaction.replace(R.id.fragment_container, fragment); 
      fragmentTransaction.commit(); 
     } else if (id == R.id.nav_start) { 
      StartFragment fragment = new StartFragment(); 
      android.support.v4.app.FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
      fragmentTransaction.replace(R.id.fragment_container, fragment); 
      fragmentTransaction.commit(); 
... 

我覺得我在初始片段集以及if語句中有很多冗餘代碼

什麼是更好的方式來壓縮代碼並換出片段而不會像這樣重複？

Answer 1

可以撥打導航抽屜這些方法只是你的片段

@Override 
     public boolean onNavigationItemSelected(MenuItem item) { 
      int id = item.getItemId(); 
      if (id == R.id.search_near) { 
       addNewFragmentWithBackStack(new FragmentOne()); 
      }else if(.....){ 
       addNewFragmentWithBackStack(new FragmentTwo()); 
      } 
      DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
      drawer.closeDrawer(GravityCompat.START); 
      return true; 

    } 

的新對象對於堆棧中

public void addNewFragmentWithBackStack(Fragment fragment) { 
    if (fragment != null) { 
     FragmentManager fragmentManager = getSupportFragmentManager(); 
     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); 
     fragmentTransaction.replace(R.id.mainContent, fragment, fragment.getClass().getSimpleName()) 
       .addToBackStack(fragment.getClass().getSimpleName()) 
       .commit(); 
    } else { 
    } 
} 

Answer 2

您可以如下創建一個函數，並傳遞一個片段對象作爲參數：

private void launchActivity(Fragement fragment) 
{ 
    android.support.v4.app.FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
    fragmentTransaction.replace(R.id.fragment_container, fragment); 
    fragmentTransaction.commit(); 
} 

現在只需創建一個對象，然後調用這個函數你需要的地方。它會避免重複的代碼。