Android的碎片沒有顯示出來

Question

我在我的Android應用程序以下代碼：

的main.xml：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
android:orientation="vertical" > 

<TextView 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="activity" /> 

<fragment 
    android:id="@+id/list" 
    android:name="com.hugo.test.FragmentA" 
    android:layout_width="0dp" 
    android:layout_height="match_parent" 
    android:layout_weight="1" /> 

</LinearLayout> 

fragmenta.xml：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
android:orientation="vertical" > 

<TextView 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="helloA" /> 

</LinearLayout> 

FragmentA.java：

package com.hugo.test; 

//some imports here 

public class FragmentA extends Fragment { 
    /** Called when the activity is first created. */ 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
    { 
     //super.onCreate(savedInstanceState); 
     //setContentView(R.layout.main); 

     return inflater.inflate(R.layout.fragmenta, container, false); 
    } 
} 

FragmentActivity.java：

package com.hugo.test; 

    //some imports here 

public class FragmentActivity extends Activity { 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
    } 
} 

活動的佈局應顯示「活動」，片段應顯示「helloA」。當我運行我的項目時，我只看到「活動」，所以在我看來，片段根本就被忽略了。

我看到的錯誤是：

12-19 09:01:05.370: E/AndroidRuntime(1352): FATAL EXCEPTION: main 
12-19 09:01:05.370: E/AndroidRuntime(1352): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.hugo.test/com.hugo.test.FragmentActivity}: android.view.InflateException: Binary XML file line #12: Error inflating class fragment 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1751) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1767) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.ActivityThread.access$1500(ActivityThread.java:122) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1005) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.os.Handler.dispatchMessage(Handler.java:99) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.os.Looper.loop(Looper.java:132) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.ActivityThread.main(ActivityThread.java:4028) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at java.lang.reflect.Method.invokeNative(Native Method) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at java.lang.reflect.Method.invoke(Method.java:491) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:844) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at dalvik.system.NativeStart.main(Native Method) 
12-19 09:01:05.370: E/AndroidRuntime(1352): Caused by: android.view.InflateException: Binary XML file line #12: Error inflating class fragment 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:688) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.view.LayoutInflater.rInflate(LayoutInflater.java:724) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.view.LayoutInflater.inflate(LayoutInflater.java:479) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.view.LayoutInflater.inflate(LayoutInflater.java:391) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.view.LayoutInflater.inflate(LayoutInflater.java:347) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:245) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.Activity.setContentView(Activity.java:1780) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at com.hugo.test.FragmentActivity.onCreate(FragmentActivity.java:11) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1048) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1715) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  ... 11 more 
12-19 09:01:05.370: E/AndroidRuntime(1352): Caused by: android.app.Fragment$InstantiationException: Unable to instantiate fragment com.hugo.test.fragmenta: make sure class name exists, is public, and has an empty constructor that is public 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.Fragment.instantiate(Fragment.java:500) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.Fragment.instantiate(Fragment.java:468) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.Activity.onCreateView(Activity.java:4132) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:664) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  ... 20 more 
12-19 09:01:05.370: E/AndroidRuntime(1352): Caused by: java.lang.ClassNotFoundException: com.hugo.test.fragmenta in loader dalvik.system.PathClassLoader[/data/app/com.jochen.test-1.apk] 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:251) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at java.lang.ClassLoader.loadClass(ClassLoader.java:540) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at java.lang.ClassLoader.loadClass(ClassLoader.java:500) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  at android.app.Fragment.instantiate(Fragment.java:490) 
12-19 09:01:05.370: E/AndroidRuntime(1352):  ... 23 more 

因爲這個錯誤的我添加了一個構造函數來FragmentA.java

public FragmentA() 
{ 

} 

此錯誤是不走了，碎片仍然不露面，和以前一樣。任何人的想法？

Answer 1

這是由於0dp討論我還沒有看到，當我複製了部分來自Android頁面。

Answer 2

這

public class FragmentActivity extends Activity { 

應該

public class FragmentActivity extends FragmentActivity { 

這也是在here