android 入门-----HelloTabWidget运行异常停止解决

在按照google的例子做HelloTabWidget时，运行HelloTabWidget程序异常停止，解决方法如下：

1. 在AndroidManifest.xml文件增加下面三行，这也是唯一例子中没有给出的代码：

<activity android:name=".AlbumsActivity"  android:label="@string/app_name"></activity> 
    <activity android:name=".ArtistsActivity"  android:label="@string/app_name"></activity> 
    <activity android:name=".SongsActivity"  android:label="@string/app_name"></activity>

[code]2. 把AlbumsActivity，ArtistsActivity和SongsActivity分别放到三个java文件里，代码按照google说明就可以。

[code]3. 添加相关图标，并建立ic_tab_albums.xml，ic_tab_artists.xml和ic_tab_songs.xml三个文件，按照google说明就可以。

[code]

[code]同样下面附上源代码：

[code]HelloTabWidget.java

[code]

package com.example.HelloTabWidget;

import android.app.TabActivity;
import android.content.Intent;
import android.content.res.Resources;
import android.os.Bundle;
import android.widget.TabHost;

public class HelloTabWidget 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, ArtistsActivity.class);

        // Initialize a TabSpec for each tab and add it to the TabHost
        spec = tabHost.newTabSpec("artists").setIndicator("Artists",
                          res.getDrawable(R.drawable.ic_tab_artists))
                      .setContent(intent);
        tabHost.addTab(spec);

        // Do the same for the other tabs
        intent = new Intent().setClass(this, AlbumsActivity.class);
        spec = tabHost.newTabSpec("albums").setIndicator("Albums",
                          res.getDrawable(R.drawable.ic_tab_albums))
                      .setContent(intent);
        tabHost.addTab(spec);

        intent = new Intent().setClass(this, SongsActivity.class);
        spec = tabHost.newTabSpec("songs").setIndicator("Songs",
                          res.getDrawable(R.drawable.ic_tab_songs))
                      .setContent(intent);
        tabHost.addTab(spec);

        tabHost.setCurrentTab(2);
    }}

AlbumsActivity.java（ArtistsActivity.java和SongsActivity.java照着改就行了）
[/code]

[code]

package com.example.HelloTabWidget;

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 Albums tab");
        setContentView(textview);
    }
}

AndroidManifest.xml[/code]

[code]

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.HelloTabWidget"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="15" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name=".HelloTabWidget"
            android:label="@string/app_name"
            android:theme="@android:style/Theme.NoTitleBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
<activity android:name=".AlbumsActivity"  android:label="@string/app_name"></activity> 
    <activity android:name=".ArtistsActivity"  android:label="@string/app_name"></activity> 
    <activity android:name=".SongsActivity"  android:label="@string/app_name"></activity>
    </application>

</manifest>

ic_tab_albums.xml（其它两个照着抄就可以了）：
[/code]

[code]

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- When selected, use grey -->
    <item android:drawable="@drawable/ic_tab_albums_grey"
          android:state_selected="true" />
    <!-- When not selected, use white-->
    <item android:drawable="@drawable/ic_tab_albums_white" />
</selector>

[/code]