java.lang.NullPointerException android

Question

這是我在控制台中看到的那個異常，但我找不到解決方案。 這是我的代碼：

public class MainActivity extends TabActivity {


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


        Resources res = getResources(); // Resource object to get Drawables
        TabHost tabHost = getTabHost();  // The activity TabHost
        TabHost.TabSpec spec;  // Resusable TabSpec for each tab

        Intent intent;  // Reusable Intent for each tab // Create an Intent to launch an Activity for the tab (to be reused)
        intent = new Intent().setClass(this, Collections.class);
        spec = tabHost.newTabSpec("Collections").setIndicator("Collections") .setContent(intent);
        tabHost.addTab(spec);

        // Do the same for the other tabs
        intent = new Intent().setClass(this, MyStampii.class);
        spec = tabHost.newTabSpec("MyStampii").setIndicator("My Stampii") .setContent(intent);
        tabHost.addTab(spec);

         // Do the same for the other tabs
        intent = new Intent().setClass(this, Notices.class);
        spec = tabHost.newTabSpec("Notices").setIndicator("Notices") .setContent(intent);
        tabHost.addTab(spec);

         // Do the same for the other tabs
        intent = new Intent().setClass(this, Tutorial.class);
        spec = tabHost.newTabSpec("Tutorial").setIndicator("Tutorial") .setContent(intent);
        tabHost.addTab(spec);

         // Do the same for the other tabs
        intent = new Intent().setClass(this, Settings.class);
        spec = tabHost.newTabSpec("Settings").setIndicator("Settings") .setContent(intent);
        tabHost.addTab(spec);
      }
}

和主要的.xml

<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/tabhost"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:padding="5dp">
        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:layout_weight="1"
            android:padding="5dp" />
        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="0" />
    </LinearLayout>
</TabHost>

這是一個例外：

[2011-07-15 09:39:19 - ddms]null
java.lang.NullPointerException
    at com.android.ddmlib.Client.sendAndConsume(Client.java:572)
    at com.android.ddmlib.HandleHello.sendHELO(HandleHello.java:142)
    at com.android.ddmlib.HandleHello.sendHelloCommands(HandleHello.java:65)
    at com.android.ddmlib.Client.getJdwpPacket(Client.java:671)
    at com.android.ddmlib.MonitorThread.processClientActivity(MonitorThread.java:317)
    at com.android.ddmlib.MonitorThread.run(MonitorThread.java:263)

任何想法？ 無論如何感謝您的幫助！

Answer 1

嘗試在 java 文件中使用

 requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
    setContentView(R.layout.tabs);
    getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.win_title); 

並像這樣制作 xml 布局

    <LinearLayout android:id="@+id/l1" android:layout_width="fill_parent" android:layout_height="fill_parent"
                  android:orientation="vertical" android:padding="5dp">

        <TabWidget android:id="@android:id/tabs" android:layout_width="fill_parent" android:layout_height="wrap_content"
                   android:scrollbars="horizontal"/>

        <FrameLayout android:id="@android:id/tabcontent" android:layout_width="fill_parent" android:layout_height="fill_parent"
                     android:padding="5dp"/>

    </LinearLayout>

希望這會奏效

Answer 2

以下鏈接是 android 標簽布局的教程，請參考更多參考： http://www.androidpeople.com/android-tabhost-tutorial-part-1