findViewById（）返回在TabActivity類

Question

空我有NewTransferActivity類，它擴展TabActivity。代碼：

public class NewTransferActivity extends TabActivity { 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.account_transfer); 

    TabHost tabHost = getTabHost(); 
    TabHost.TabSpec spec; 

    spec = tabHost.newTabSpec("receiver").setIndicator("Rec").setContent(getReceiverTab()); 
    tabHost.addTab(spec); 

    spec = tabHost.newTabSpec("transfer").setIndicator("Trans").setContent(getTransferTab()); 
    tabHost.addTab(spec); 

} 

private TabContentFactory getReceiverTab(){ 
    TabContentFactory factory = new TabContentFactory() { 
     @Override 
     public View createTabContent(String tag) { 

      ... 

      return layout; 
     } 
    }; 
    return factory; 
} 

private TabContentFactory getTransferTab(){ 
    TabContentFactory factory = new TabContentFactory() { 

     @Override 
     public View createTabContent(String tag) { 
      LinearLayout layout = (LinearLayout) findViewById(R.id.mytrans); 

      if (layout == null){ 
       //layout = new LinearLayout(NewTransferActivity.this); 
       System.out.println("NULL>>>>>>"); 
       return new LinearLayout(NewTransferActivity.this); 
      } 
      return layout; 
     } 
    }; 
    return factory; 
} ... 

我的XML文件，它包含的佈局是：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:id="@+id/mytrans" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="vertical" > 


<TextView 
    android:id="@+id/textView1" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:text="Medium Text" 
    android:textAppearance="?android:attr/textAppearanceMedium" /> 

<EditText 
    android:id="@+id/editText1" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" > 

    <requestFocus /> 
</EditText> 


<TextView 
    android:id="@+id/textView2" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:text="Medium Text" 
    android:textAppearance="?android:attr/textAppearanceMedium" /> 

<EditText 
    android:id="@+id/editText2" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" /> 


<TextView 
    android:id="@+id/textView3" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:text="Medium Text" 
    android:textAppearance="?android:attr/textAppearanceMedium" /> 

<EditText 
    android:id="@+id/editText3" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" /> 


<TextView 
    android:id="@+id/textView4" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:text="Medium Text" 
    android:textAppearance="?android:attr/textAppearanceMedium" /> 

<EditText 
    android:id="@+id/editText4" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" /> 

</LinearLayout> 

我想加載佈局從XML文件中的單個標籤，我definded。不幸的是，我得到NullPointerException，因爲方法getTransferTab（）中佈局爲null。 'LinearLayout layout =（LinearLayout）findViewById（R.id.mytrans）'返回null。我做錯了什麼？提前致謝。

Answer 1

你還是嘗試使用LayoutInflater從XML獲取視圖層次，

TabContentFactory factory = new TabContentFactory() { 
     @Override 
     public View createTabContent(String tag) { 

      LayoutInflater inflater = LayoutInflater.from(Activity_Name.this); 
      View linearLayout = inflater.inflate(R.layout.mytrans, null); 

      return linearLayout; 
     } 
    }; 

Answer 2

我的第一個想法是，在這條線：

LinearLayout layout = (LinearLayout) findViewById(R.id.mytrans); 

您所呼叫的你TabContentFactory

的findViewById方法你需要調用位於Activity該命令的版本。