如何在onCreate中打開一個隨機片段進行活動？

Question

我想在啓動MainAcitivity時在我的framelayout中打開一個隨機片段。

問題：

1. 我如何random1值轉換爲一個片段？

2. 當按下屏幕上的按鈕時，刷新視圖以獲取另一個隨機片段是否很困難？

   public class Beginner extends ActionBarActivity { 
   
   private SoundPool spool; 
   public int soundID_R1; 
   public int soundID_R5; 
   public int soundID_R8; 
   
   private Fragment_gehorINTbeginnerR1 intBegFragment_R1; 
   private Fragment_gehorINTbeginnerR5 intBegFragment_R5; 
   private Fragment_gehorINTbeginnerR8 intBegFragment_R8; 
   private int randomFragmentNum; 
   private FrameLayout container; 
   private FragmentTransaction fragmentTransaction; 
   
   @Override 
   protected void onCreate(Bundle savedInstanceState) { 
       super.onCreate(savedInstanceState); 
       setContentView(R.layout.fragment_beginner); 
   
       initUI(); 
   } 
   
   private void initUI() { 
       container = (FrameLayout) findViewById(R.id.beginner_frame); 
       fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
       setRandomFragment(); 
   } 
   
   private void setRandomFragment() { 
       Random random = new Random(); 
       randomFragmentNum = random.nextInt(2); 
       //random choose fragment 
       switch (randomFragmentNum) { 
        case 0: { 
         intBegFragment_R1 = new Fragment_gehorINTbeginnerR1(); 
         fragmentTransaction.replace(R.id.beginner_frame, intBegFragment_R1); 
         fragmentTransaction.commit(); 
         break; 
        } 
        case 1: { 
         intBegFragment_R5 = new Fragment_gehorINTbeginnerR5(); 
         fragmentTransaction.replace(R.id.beginner_frame, intBegFragment_R5); 
         fragmentTransaction.commit(); 
         break; 
        } 
        case 2: { 
         intBegFragment_R8 = new Fragment_gehorINTbeginnerR8(); 
         fragmentTransaction.replace(R.id.beginner_frame, intBegFragment_R8); 
         fragmentTransaction.commit(); 
         break; 
        } 
       } 
   } 
   

Answer 1

問題是隨機：用於三個片段之間隨機選擇的非常小的參數。這段代碼可以幫助你。請setRandomFragment（）插入：

randomFragmentNum = random.nextInt(150); 
     if (randomFragmentNum < 50) { 
      randomFragmentNum = 0; 
     } else if (randomFragmentNum < 100) { 
      randomFragmentNum = 1; 
     } else randomFragmentNum = 2; 

更新2： 五年片段

randomFragmentNum = random.nextInt(250); 
      if (randomFragmentNum < 50) { 
       randomFragmentNum = 0; 
      } else if (randomFragmentNum < 100) { 
       randomFragmentNum = 1; 
      } else if (randomFragmentNum < 150) { 
       randomFragmentNum = 2; 
      } else if (randomFragmentNum < 200) { 
       randomFragmentNum = 3; 
      } else 
       randomFragmentNum = 4; 
      } 

Answer 2

這是一個例子：

switch(random1.nextInt(3)){ 
     case 0: setMyFragment(new Fragment_gehorINTbeginnerR1()); 
       break; 
     case 1: setMyFragment(new Fragment_gehorINTbeginnerR5()); 
       break; 
     case 2: setMyFragment(new Fragment_gehorINTbeginnerR8()); 
       break; 
    } 

我使用的方法來加載我的片段：

public void setMyFragment(Fragment fr){ 
    try{ 
     FragmentManager fm = getSupportFragmentManager(); 
     if(fr != null){ 
      FragmentTransaction ft = fm.beginTransaction(); 
      ft.replace(R.id.Mainfragment, fr, null); 
          ft.commitAllowingStateLoss(); 
     } 
    }catch(IllegalStateException e) {   
     Log.e(TAG, "ISE setting main view "+e.getMessage()); 
    }  
} 

Answer 3

簡單溶液（UPDATE 2）。如果使用2個隨機片段必須在random.getInt（）值100集，如果三個片段 - 150，四 - 200 ...並添加塊的if-else邏輯選擇片段：

/** 
    * Created by scijoker on 2/14/14. 
    */ 
    public class TestRandomFragmentActivity extends FragmentActivity { 
     private LoginFragment loginFragment; 
     private SignUpFragment signUpFragment; 
     private FragmentTransaction fragmentTransaction; 

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

      initUI(); 
     } 

     private void initUI() { 
      fragmentTransaction = getSupportFragmentManager().openTransaction(); 
      setRandomFragment(); 
     } 

     private void setRandomFragment() { 
      Random random = new Random(); 
      int randomFragmentNum = random.nextInt(100); 
     if (randomFragmentNum < 50) { 
      randomFragmentNum = 0; 
     } else{ 
      randomFragmentNum = 1; 
     } 
      //random choose fragment 
      switch (randomFragmentNum) { 
       case 0: { 
        loginFragment = new LoginFragment(); 
        fragmentTransaction.add(R.id.fl_container, loginFragment); 
        fragmentTransaction.commit() 
        break; 
       } 
       case 1: { 
        signUpFragment = new SignUpFragment(); 
        fragmentTransaction.add(R.id.fl_container, signUpFragment); 
        fragmentTransaction.commit() 
        break; 
       } 
      } 
     }