我的listview有问题。我有一个列表whit标题。
列表：artistas_list header：artistas_list_s
在标题中我要写一个字母（A，B，C，D，....）
除了滚动列表外，一切正常。当滚动在此行中出现空指针异常时：tt.setText（o.nombre）;
这很奇怪，因为在第一时间工作正常。
好的...然后粘贴getView的代码
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.artistas_list, null);
}
Object content = null;
Artista o = artistas.get(position);
try {
URL url = new URL(o.foto);
content = url.getContent();
} catch (Exception ex) {
ex.printStackTrace();
}
InputStream is = (InputStream) content;
Drawable image = Drawable.createFromStream(is, "src");
TextView tt = (TextView) v.findViewById(R.id.ArtistTopText);
TextView nid = (TextView) v.findViewById(R.id.txtnid);
ImageView it = (ImageView) v.findViewById(R.id.imageView1);
tt.setText(o.nombre);
nid.setText(o.nid);
it.setImageDrawable(image);
String letra= o.nombre.substring(0, 1);
if(!letra.equals(letraA)){
LayoutInflater vo = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vo.inflate(R.layout.artistas_list_s, null);
}
letraA = letra;
return v;
}
好的，请阅读并尝试帮助!!!
logcat的：
08-28 09:45:24.283: E/AndroidRuntime(512): FATAL EXCEPTION: main
08-28 09:45:24.283: E/AndroidRuntime(512): java.lang.NullPointerException
08-28 09:45:24.283: E/AndroidRuntime(512): at es.okisam.comedy.artistas.ArtistasActivity$ListAdaptor.getView(ArtistasActivity.java:95)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.widget.AbsListView.obtainView(AbsListView.java:1409)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.widget.ListView.makeAndAddView(ListView.java:1745)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.widget.ListView.fillDown(ListView.java:670)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.widget.ListView.fillGap(ListView.java:641)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.widget.AbsListView.trackMotionScroll(AbsListView.java:3399)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.widget.AbsListView.onTouchEvent(AbsListView.java:2233)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.widget.ListView.onTouchEvent(ListView.java:3446)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.view.View.dispatchTouchEvent(View.java:3885)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:903)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
08-28 09:45:24.283: E/AndroidRuntime(512): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1691)
08-28 09:45:24.283: E/AndroidRuntime(512): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1125)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.app.Activity.dispatchTouchEvent(Activity.java:2096)
08-28 09:45:24.283: E/AndroidRuntime(512): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1675)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.view.ViewRoot.deliverPointerEvent(ViewRoot.java:2194)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.view.ViewRoot.handleMessage(ViewRoot.java:1878)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.os.Handler.dispatchMessage(Handler.java:99)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.os.Looper.loop(Looper.java:130)
08-28 09:45:24.283: E/AndroidRuntime(512): at android.app.ActivityThread.main(ActivityThread.java:3683)
08-28 09:45:24.283: E/AndroidRuntime(512): at java.lang.reflect.Method.invokeNative(Native Method)
08-28 09:45:24.283: E/AndroidRuntime(512): at java.lang.reflect.Method.invoke(Method.java:507)
08-28 09:45:24.283: E/AndroidRuntime(512): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-28 09:45:24.283: E/AndroidRuntime(512): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-28 09:45:24.283: E/AndroidRuntime(512): at dalvik.system.NativeStart.main(Native Method)
artistas_list_s
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/textSeparator"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#000"
android:gravity="center"
android:text="text"
android:textColor="#FFFFFFFF"
android:visibility="visible" />
</LinearLayout>
artistas_list
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/RelativeLayout1"
android:layout_width="fill_parent"
android:layout_height="?android:attr/listPreferredItemHeight"
android:background="@drawable/fondo"
android:baselineAligned="false"
android:gravity="center_vertical|top"
android:orientation="horizontal"
android:padding="6dip" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_margin="5dp"
android:adjustViewBounds="true"
android:background="@drawable/border_images"
android:maxHeight="50dp"
android:maxWidth="50dp"
android:minHeight="50dp"
android:minWidth="50dp"
android:scaleType="fitXY"
android:src="@drawable/ic_launcher" />
<TextView
android:id="@+id/ArtistTopText"
android:layout_width="190dp"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_toLeftOf="@+id/txtnid"a
android:layout_toRightOf="@+id/imageView1"
android:layout_weight="0.02"
android:gravity="center_vertical"
android:singleLine="true"
android:textColor="#000" />
<TextView
android:id="@+id/txtnid"
android:layout_width="1dp"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:gravity="center_vertical"
android:singleLine="true"
android:visibility="gone" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_weight="1"
android:src="@drawable/estrella_destacados"
android:visibility="gone" />
<ImageView
android:id="@+id/imageView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_marginRight="24dp"
android:layout_weight="1"
android:src="@drawable/flecha" />
</RelativeLayout>
使用logcat和布局进行更新。 Remmember ... nullpointer在滚动时出现......：S
答案 0 :(得分：1)
你不应该这样做
content = url.getContent();
开头，因为它在UI线程中运行。
然后，
InputStream is = (InputStream) content;
可以为null，因为它位于try {} catch {}块
之外最后，鉴于我们没有堆栈跟踪或任何日志，它可能是您代码中的任何内容（视图中不存在视图，对象具有空字段......）
另外，你的设计很奇怪。如果你的元素没有与前一个元素相同的字母，你不显示它，而只显示它的初始值？
仔细观察后，代码中会发生以下情况：
请参阅此示例http://w2davids.wordpress.com/android-sectioned-headers-in-listviews/，了解您似乎要尝试做的事情。