我已经按照几个不同的教程，没有任何运气让这个工作。我能看到的唯一区别是我使用数据库从中提取数据，并且教程创建了一个数组来获取数据。
以下是我正在使用的代码，看看是否有人可以帮助我。
main.xml文件：
<?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">
<TabWidget android:id="@android:id/tabs"
android:layout_width="fill_parent" android:layout_height="wrap_content" />
<FrameLayout android:id="@android:id/tabcontent"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<ListView android:layout_width="fill_parent" android:id="@+id/listView1"
android:layout_height="wrap_content"></ListView>
<ListView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/listView2">
</ListView>
</FrameLayout>
</LinearLayout>
main.java文件：
import android.app.TabActivity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.TabHost;
import android.widget.TabHost.OnTabChangeListener;
import android.widget.TabHost.TabContentFactory;
import com.facebook.android.R;
public class MainLib extends TabActivity implements OnTabChangeListener {
private static final String TAG = "MainLib";
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mainlib);
//final TabHost tabHost = (TabHost) findViewById(android.R.id.tabhost);
//tabHost.setup();
TabHost mTabHost = getTabHost();
mTabHost.setOnTabChangedListener(this);
// Find your views NEW LIBS
final ListView listPro = (ListView) findViewById(R.id.listView1);
final DBLibAdapter db = new DBLibAdapter(this);
db.open();
final Cursor c = db.getAllNewLibs();
startManagingCursor(c);
Log.d(TAG, "New Libs Cursor Created");
// Create the adapter
NewLibAdapter adapter = new NewLibAdapter(this, c);
listPro.setAdapter(adapter);
Log.d(TAG, "New Libs Adapter Created");
db.close();
listPro.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
db.open();
db.updateId(id);
db.close();
Intent miamor = new Intent(MainLib.this, Result.class);
startActivity(miamor);
}
});
// Find your views SAVED LIBS
final ListView listPro1 = (ListView) findViewById(R.id.listView2);
db.open();
final Cursor c1 = db.getAllSavedLibs();
startManagingCursor(c1);
Log.d(TAG, "Saved Libs Cursor Created");
// Create the adapter
SavedLibAdapter adapter1 = new SavedLibAdapter(this, c1);
listPro1.setAdapter(adapter1);
Log.d(TAG, "Saved Libs Adapter Created");
db.close();
listPro1.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
db.open();
db.updateId(id);
db.close();
Intent amormio = new Intent(MainLib.this, Result.class);
startActivity(amormio);
}
});
mTabHost.addTab(mTabHost.newTabSpec("New Libs").setIndicator("New Libs")
.setContent(new TabContentFactory(){
@Override
public View createTabContent(String arg0) {
return listPro;
}
}));
mTabHost.addTab(mTabHost.newTabSpec("Saved Libs").setIndicator("Saved Libs")
.setContent(new TabContentFactory(){
@Override
public View createTabContent(String tag) {
return listPro1;
}
}));
mTabHost.setCurrentTab(0);
}
public void onTabChanged(String tabName) {
if(tabName.equals("New Libs")) {
//do something
}
else if(tabName.equals("Saved Libs")) {
//do something
}
}
}
第一个listView有数据但第二个没有。我试图删除第二个，但它仍然会抛出一条错误消息：
05-18 16:57:30.964: ERROR/AndroidRuntime(32753): Uncaught handler: thread main exiting due to uncaught exception
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): java.lang.NullPointerException
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.widget.TabHost.dispatchWindowFocusChanged(TabHost.java:295)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.widget.TabHost.dispatchWindowFocusChanged(TabHost.java:295)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.view.ViewRoot.handleMessage(ViewRoot.java:1819)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.os.Handler.dispatchMessage(Handler.java:99)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.os.Looper.loop(Looper.java:123)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at android.app.ActivityThread.main(ActivityThread.java:4363)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at java.lang.reflect.Method.invokeNative(Native Method)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at java.lang.reflect.Method.invoke(Method.java:521)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
05-18 16:57:30.984: ERROR/AndroidRuntime(32753): at dalvik.system.NativeStart.main(Native Method)
请帮忙！
答案 0 :(得分：0)
您在主布局中包含ListView。您需要为每个活动创建布局。您正在按需创建布局，但随后引用另一个布局（主要）中的列表视图。
有关示例，请参阅选项卡布局教程：http://developer.android.com/resources/tutorials/views/hello-tabwidget.html。