Android ViewPager 出现 ClassNotFoundException

Question

我遇到了以下错误，但我不理解它的含义...

06-15 22:06:49.196: W/dalvikvm(17622): threadid=1: thread exiting with uncaught exception (group=0x40bcc1f8)
06-15 22:07:05.031: W/dalvikvm(17877): threadid=1: thread exiting with uncaught exception (group=0x40bcc1f8)
06-15 22:07:05.031: E/AndroidRuntime(17877): FATAL EXCEPTION: main
06-15 22:07:05.031: E/AndroidRuntime(17877): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.whipple.android/com.whipple.android.StockActivity}: android.view.InflateException: Binary XML file line #6: Error inflating class ViewPager
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1968)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1993)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.ActivityThread.access$600(ActivityThread.java:127)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1159)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.os.Handler.dispatchMessage(Handler.java:99)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.os.Looper.loop(Looper.java:137)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.ActivityThread.main(ActivityThread.java:4512)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at java.lang.reflect.Method.invokeNative(Native Method)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at java.lang.reflect.Method.invoke(Method.java:511)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:794)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:561)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at dalvik.system.NativeStart.main(Native Method)
06-15 22:07:05.031: E/AndroidRuntime(17877): Caused by: android.view.InflateException: Binary XML file line #6: Error inflating class ViewPager
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:691)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.rInflate(LayoutInflater.java:739)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:272)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.Activity.setContentView(Activity.java:1851)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at com.whipple.android.StockActivity.onCreate(StockActivity.java:17)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.Activity.performCreate(Activity.java:4481)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1052)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1932)
06-15 22:07:05.031: E/AndroidRuntime(17877):    ... 11 more
06-15 22:07:05.031: E/AndroidRuntime(17877): Caused by: java.lang.ClassNotFoundException: android.view.ViewPager
06-15 22:07:05.031: E/AndroidRuntime(17877):    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:61)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.createView(LayoutInflater.java:552)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.onCreateView(LayoutInflater.java:636)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:66)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.onCreateView(LayoutInflater.java:653)
06-15 22:07:05.031: E/AndroidRuntime(17877):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:678)
06-15 22:07:05.031: E/AndroidRuntime(17877):    ... 21 more

这是我的代码...

public class StockActivity extends Activity {
public ListAdapter listadapter;
private StockPageAdapter myAdapter;
private ViewPager myPager;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    super.setContentView(R.layout.main);

    this.myAdapter = new StockPageAdapter(this);
    this.myPager = (ViewPager)super.findViewById(R.id.pager);
    this.myPager.setAdapter(myAdapter);
}

这是一个带有ViewPager的ListAdapter，可以通过滚动列表来使用。我扩展了BaseAdapter并使用以下代码填充视图...

LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(R.layout.row, null);

请问有人能帮我理解哪里出了问题吗？

- Dakota Jay Whipple

Answer 1

你的布局文件中的XML长什么样子？如果你只是简单地放置了

<ViewPager
    android:layout_width="..."
    android:layout_height="..." />

你的应用程序将崩溃，因为ViewPager不位于核心SDK包中，而是在支持库中。你需要放置完全限定名称。

<android.support.v4.view.ViewPager
    android:layout_width="..."
    android:layout_height="..." />

另外，正如其他人所提到的那样，确保支持库JAR文件已经正确地包含在您的项目中。

希望这可以帮到你。

- devunwired

---

是的，我完全忘记了那个。已经更改了，现在我要解决下一个错误了。._. 谢谢。 - Dakota Jay Whipple

Answer 2

我认为你使用了太多的 "super" 前缀。

尝试这样做：

@Override   
public void onCreate(Bundle savedInstanceState) {   
    super.onCreate(savedInstanceState);   
    setContentView(R.layout.main);   

    this.myAdapter = new StockPageAdapter(this);   
    this.myPager = (ViewPager)findViewById(R.id.pager);   
    this.myPager.setAdapter(myAdapter);   
}   

此外，请确保android-support-v4.jar文件在一个名为libs的目录中（该目录应与res、src和assets处于同一级别，位于项目中）。自ADT 17版本以后，这是必须的。只需创建该目录，将.jar文件放入其中，Eclipse会处理其余部分，无需手动添加到构建路径或其他任何操作。

- Barak

---

是的，它已经在那里了。第二个super是多余的，但我把它拿掉了，仍然得到相同的结果。 - Dakota Jay Whipple