無法開始Fragement交易

Question

我試圖片段添加到活動，但是當我beginTransaction方法片段添加到活動編譯器返回錯誤

cannot resolve method add

的onCreate函數，其中錯誤返回

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
    if (savedInstanceState == null) { 
     getSupportFragmentManager().beginTransaction() 
       .add(R.id.contain, new PlaceholderFragment()) 
       .commit(); 
    } 
} 

片段

public static class PlaceholderFragment extends Fragment { 

    public PlaceholderFragment() { 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     final View rootView = inflater.inflate(R.layout.start, container, false); 
     rootView.findViewById(R.id.start).setOnClickListener((View.OnClickListener) this); 
     return rootView; 
    } 
} 

main.xml中

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

start.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="horizontal"> 

<LinearLayout 
    android:layout_gravity="center" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:gravity="center" 
    android:orientation="vertical"> 
    <at.markushi.ui.CircleButton 
     android:id="@+id/start" 
     android:layout_width="163dp" 
     android:layout_height="162dp" 
     app:cb_pressedRingWidth="8dip" 
     android:layout_gravity="center_horizontal|bottom" 
     android:layout_alignParentBottom="true" 
     android:layout_alignLeft="@+id/image" 
     android:layout_alignStart="@+id/image" 
     android:src="@drawable/start" 
     android:layout_marginBottom="37dp" 
     android:layout_alignRight="@+id/image" 
     android:layout_alignEnd="@+id/image" 
     android:layout_below="@+id/image" /> 
</LinearLayout> 

消息搖籃建立

Error:(77, 21) error: no suitable method found for add(int,PlaceholderFragment) method FragmentTransaction.add(Fragment,String) is not applicable (argument mismatch; int cannot be converted to Fragment) method FragmentTransaction.add(int,Fragment) is not applicable (argument mismatch; PlaceholderFragment cannot be converted to Fragment)

Answer 1

記得用，而不是

import android.support.v4.app.Fragment; 

import android.app.Fragment; 

，使得您的片段來自支持庫。否則，編譯器無法解析方法add的參數類型，從而導致錯誤。

Answer 2

更改您的擴展活動，以FragmentActivity爲了支持其內部片段