Android 为什么我使用StickyGridHeaders库得到一个NullPointerException,而其他人使用相同的库却很好?
我在中得到了一个Android 为什么我使用StickyGridHeaders库得到一个NullPointerException,而其他人使用相同的库却很好?,android,gridview,nullpointerexception,android-gridview,Android,Gridview,Nullpointerexception,Android Gridview,我在中得到了一个NullPointerException,而其他()和()似乎在毫无例外地使用它 我可能还应该提到,我正在项目中添加库的.jar文件,因为我使用Eclipse(而不是Android Studio) 我怎样才能解决这个问题 Logcat的一部分: SSCCE: MainActivity.java: 我只是让它在Eclipse中工作。以下是我所做的: 在Eclipse中创建一个名为StickyGridHeaders的新项目。让它成为一个 库项目并制作一个包 com.tonicarto
NullPointerException
,而其他()和()似乎在毫无例外地使用它
我可能还应该提到,我正在项目中添加库的.jar
文件,因为我使用Eclipse(而不是Android Studio)
我怎样才能解决这个问题
Logcat的一部分:
SSCCE:
MainActivity.java:
我只是让它在Eclipse中工作。以下是我所做的:
StickyGridHeaders
的新项目。让它成为一个
库项目并制作一个包
com.tonicartos.widget.stickygridheaders
在其中。不创建
任何活动header.xml
和item.xml
中,
在TextView
元素中,添加android:id=“@android:id/item1”
属性感谢Mike M.对这一步的评论getView()
方法提到的,但是这一行在getItemViewType()
方法中,并且也不调用getView()
因此我得出结论,
.jar
是该项目的早期版本。它看起来像是在标题和项目布局中的TextView
s上需要ID;特别是@android:id/text1
,如果链接的代码实际上是您正在运行的。完整的堆栈跟踪将很有帮助。有关Mike注释的说明,请访问:和。@MikeM。在问题中发布了完整的堆栈跟踪我刚刚测试了您发布的代码和链接的回购代码,这是唯一的错误。如果您确定已将android:id=“@android:id/text1”
添加到发布版面中的两个TextView
中,请尝试清理/重建项目。如果仍然存在问题,您可能需要执行更多步骤。正如我所记得的,Eclipse可能非常不合作。卸载/重新安装应用程序、重新启动IDE、重新启动设备/仿真器、再次清理/重建等。如果您已经完成所有这些操作,但它仍然崩溃,请检查堆栈跟踪是否发生了更改,即使只是行号。
...
06-24 08:42:22.419: E/AndroidRuntime(1495): FATAL EXCEPTION: main
06-24 08:42:22.419: E/AndroidRuntime(1495): java.lang.NullPointerException
06-24 08:42:22.419: E/AndroidRuntime(1495): at com.tonicartos.widget.stickygridheaders.StickyGridHeadersSimpleArrayAdapter.getHeaderView(StickyGridHeadersSimpleArrayAdapter.java:93)
...
public class MainActivity extends Activity {
private static final String TAG = MainActivity.class.getSimpleName();
private StickyGridHeadersGridView mainGridView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainGridView = (StickyGridHeadersGridView) findViewById(R.id.mainActivity_gridView);
final String[] dataArray = {
"A",
"B",
"C",
"D",
"E",
"F",
"G",
"H",
"I",
"J",
};
StickyGridHeadersSimpleArrayAdapter<String> stickyGridHeadersSimpleAdapter =
new StickyGridHeadersSimpleArrayAdapter<String>(
getApplicationContext(), dataArray, R.layout.header,
R.layout.item);
mainGridView.setAdapter(stickyGridHeadersSimpleAdapter);
mainGridView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Log.i(TAG, "Item labelled " + dataArray[position] + "clicked.");
}
});
}
}
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${relativePackage}.${activityClass}" >
<com.tonicartos.widget.stickygridheaders.StickyGridHeadersGridView android:id="@+id/mainActivity_gridView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center_horizontal"
android:background="#90000000"
android:gravity="center"
android:horizontalSpacing="10dp"
android:verticalSpacing="10dp"
android:numColumns="4"
android:stretchMode="columnWidth" />
</RelativeLayout>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="10dp"
android:textColor="#fff" />
<FrameLayout
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#ff33b5e5" >
</FrameLayout>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="10dp"
android:textColor="#fff" />
06-24 08:42:22.415: W/dalvikvm(1495): threadid=1: thread exiting with uncaught exception (group=0xa62ad288)
06-24 08:42:22.419: E/AndroidRuntime(1495): FATAL EXCEPTION: main
06-24 08:42:22.419: E/AndroidRuntime(1495): java.lang.NullPointerException
06-24 08:42:22.419: E/AndroidRuntime(1495): at com.tonicartos.widget.stickygridheaders.StickyGridHeadersSimpleArrayAdapter.getHeaderView(StickyGridHeadersSimpleArrayAdapter.java:93)
06-24 08:42:22.419: E/AndroidRuntime(1495): at com.tonicartos.widget.stickygridheaders.StickyGridHeadersSimpleAdapterWrapper.getHeaderView(StickyGridHeadersSimpleAdapterWrapper.java:57)
06-24 08:42:22.419: E/AndroidRuntime(1495): at com.tonicartos.widget.stickygridheaders.StickyGridHeadersBaseAdapterWrapper.getView(StickyGridHeadersBaseAdapterWrapper.java:172)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.AbsListView.obtainView(AbsListView.java:2267)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.GridView.onMeasure(GridView.java:1030)
06-24 08:42:22.419: E/AndroidRuntime(1495): at com.tonicartos.widget.stickygridheaders.StickyGridHeadersGridView.onMeasure(StickyGridHeadersGridView.java:822)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.View.measure(View.java:15172)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:617)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:399)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.View.measure(View.java:15172)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.View.measure(View.java:15172)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1390)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.LinearLayout.measureVertical(LinearLayout.java:681)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.View.measure(View.java:15172)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
06-24 08:42:22.419: E/AndroidRuntime(1495): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2148)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.View.measure(View.java:15172)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1848)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1100)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1273)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4212)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.Choreographer.doCallbacks(Choreographer.java:555)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.Choreographer.doFrame(Choreographer.java:525)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.os.Handler.handleCallback(Handler.java:615)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.os.Handler.dispatchMessage(Handler.java:92)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.os.Looper.loop(Looper.java:137)
06-24 08:42:22.419: E/AndroidRuntime(1495): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-24 08:42:22.419: E/AndroidRuntime(1495): at java.lang.reflect.Method.invokeNative(Native Method)
06-24 08:42:22.419: E/AndroidRuntime(1495): at java.lang.reflect.Method.invoke(Method.java:511)
06-24 08:42:22.419: E/AndroidRuntime(1495): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-24 08:42:22.419: E/AndroidRuntime(1495): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-24 08:42:22.419: E/AndroidRuntime(1495): at dalvik.system.NativeStart.main(Native Method)
06-24 08:47:22.611: I/Process(1495): Sending signal. PID: 1495 SIG: 9