Hi Shawn_Chiu,
you had not override onCreate() method of HelloTabActivity class.
override it as
public void onCreate(Bundle savedInstanceState)
{
super.onCreate (savedInstanceState);
}
your activity is extending from TabActivity, so remove line
setContentView(R.layout.main); from onCreate () method.
On Nov 23, 6:50 am, Shawn_Chiu <[email protected]> wrote:
> Hi, all
> I encountered an excepiton when I used TabActivity. Each tab content
> is a seperate activity.
> Could anyone give me a hand ?Thanks :-)
>
> The exception stack trace is as follow:
> -------------------------------------------------------------------------------------------------------------
> Thread [<3> main] (Suspended (exception NullPointerException))
> TabHost.dispatchWindowFocusChanged(boolean) line: 295
> FrameLayout(ViewGroup).dispatchWindowFocusChanged(boolean) line: 661
> LinearLayout(ViewGroup).dispatchWindowFocusChanged(boolean) line:
> 661
> PhoneWindow$DecorView(ViewGroup).dispatchWindowFocusChanged(boolean)
> line: 661
> ViewRoot.handleMessage(Message) line: 1819
> ViewRoot(Handler).dispatchMessage(Message) line: 99
> Looper.loop() line: 123
> ActivityThread.main(String[]) line: 4363
> Method.invokeNative(Object, Object[], Class, Class[], Class, int,
> boolean) line: not available [native method]
> Method.invoke(Object, Object...) line: 521
> ZygoteInit$MethodAndArgsCaller.run() line: 860
> ZygoteInit.main(String[]) line: 618
> NativeStart.main(String[]) line: not available [native method]
> -------------------------------------------------------------------------------------------------------------
>
> layout/main.xml
> -------------------------------------------------------------------------------------------------------------
> <?xml version="1.0" encoding="utf-8"?>
> <TabHost xmlns:android="http://schemas.android.com/apk/res/android";
> android:id="@+id/tabhost"
> android:layout_width="fill_parent"
> android:layout_height="fill_parent"
> android:layout_weight="1">
>
> <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="wrap_content"
> android:paddingTop="64dip">
> </FrameLayout>
> </TabHost>
> -------------------------------------------------------------------------------------------------------------
> strings.xml
> ------------------------------------------------------------------------------------------------------------
> <?xml version="1.0" encoding="utf-8"?>
> <resources>
> <string name="hello">Hello World, HelloTabActivity!</string>
> <string name="app_name">HelloTabWidget</string>
> <string name="song">song</string>
> <string name="album">album</string>
> <string name="acc">acc</string>
> </resources>
> -----------------------------------------------------------------------------------------------------------
>
> classes are placed into com.qiu.test package.
>
> HelloTabActivity.java
> ------------------------------------------------------------------------------------------------------------------
> package com.qiu.test;
>
> import android.app.Activity;
> import android.app.TabActivity;
> import android.content.Intent;
> import android.content.res.Resources;
> import android.os.Bundle;
> import android.widget.ScrollView;
> import android.widget.TabHost;
>
> public class HelloTabActivity extends TabActivity {
> protected TabHost tabs;
>
> protected void OnCreate (Bundle bundle)
> {
> super.onCreate (bundle);
> setContentView(R.layout.main);
>
> tabs = getTabHost();
>
> Resources res = getResources();
>
> TabHost.TabSpec syncTabSpec = tabs.newTabSpec("sync");
> syncTabSpec.setContent (new Intent (this,
> SongActivity.class));
> syncTabSpec.setIndicator("sync");
> tabs.addTab(syncTabSpec);
>
> TabHost.TabSpec accTabSpec = tabs.newTabSpec("acc");
> accTabSpec.setContent (new Intent (this,
> AlbumsActivity.class));
> accTabSpec.setIndicator("acc");
> tabs.addTab(accTabSpec);
>
> tabs.setCurrentTab(0);
> }}
>
> ------------------------------------------------------------------------------------------------------------------
>
> SongActivity.java
> ------------------------------------------------------------------------------------------------------------------
> package com.qiu.test;
>
> import android.app.Activity;
> import android.os.Bundle;
> import android.widget.TextView;
>
> public class SongActivity extends Activity {
>
> public void onCreate (Bundle savedInstanceState)
> {
> super.onCreate (savedInstanceState);
>
> TextView textview = new TextView (this);
> textview.setText("This is the song tab");
> setContentView (textview);
> }}
>
> ----------------------------------------------------------------------------------------------------------------
> AlbumsActivity.java
> ----------------------------------------------------------------------------------------------------------
> package com.qiu.test;
>
> import android.app.Activity;
> import android.os.Bundle;
> import android.widget.TextView;
>
> public class AlbumsActivity extends Activity {
>
> public void onCreate (Bundle savedInstanceState)
> {
> super.onCreate (savedInstanceState);
>
> TextView textview = new TextView (this);
> textview.setText("This is the albumns tab");
> setContentView (textview);
> }}
>
> -----------------------------------------------------------------------------------------------------------------
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