在我的应用程序中,我使用 Android 的 Navigation Drawer 组件。从这个活动我开始另一个不使用导航抽屉的活动,但应用程序崩溃并出现此错误:
07-15 08:52:49.441: E/AndroidRuntime(1639): FATAL EXCEPTION: main
07-15 08:52:49.441: E/AndroidRuntime(1639): java.lang.NullPointerException
07-15 08:52:49.441: E/AndroidRuntime(1639): at com.app.UserProfileActivity$detailUserAdapter.getView(UserProfileActivity.java:143)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.AbsListView.obtainView(AbsListView.java:2143)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.ListView.measureHeightOfChildren(ListView.java:1246)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.ListView.onMeasure(ListView.java:1158)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.View.measure(View.java:15518)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.RelativeLayout.measureChild(RelativeLayout.java:666)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.View.measure(View.java:15518)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:681)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:461)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.View.measure(View.java:15518)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.View.measure(View.java:15518)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.View.measure(View.java:15518)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
07-15 08:52:49.441: E/AndroidRuntime(1639): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2176)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.View.measure(View.java:15518)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1874)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1089)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1265)
07-15 08:52:49.441: E/AndroidRuntime(1639): at
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
07-15 08:52:49.441: E/AndroidRuntime(1639): at
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.os.Handler.handleCallback(Handler.java:725)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.os.Handler.dispatchMessage(Handler.java:92)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.os.Looper.loop(Looper.java:137)
07-15 08:52:49.441: E/AndroidRuntime(1639): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-15 08:52:49.441: E/AndroidRuntime(1639): at java.lang.reflect.Method.invokeNative(Native Method)
07-15 08:52:49.441: E/AndroidRuntime(1639): at java.lang.reflect.Method.invoke(Method.java:511)
07-15 08:52:49.441: E/AndroidRuntime(1639): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-15 08:52:49.441: E/AndroidRuntime(1639): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-15 08:52:49.441: E/AndroidRuntime(1639): at dalvik.system.NativeStart.main(Native Method)
我的第一个活动的 xml 布局是:
<android.support.v4.widget.DrawerLayout
android:id="@+id/slideMenu_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@id/relativeLayoutBanner" >
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@null" >
<RelativeLayout
>
<EditText
>
<requestFocus />
</EditText>
<ListView
>
</ListView>
<ImageView
/>
<TextView
/>
<TextView
/>
<ProgressBar
/>
</RelativeLayout>
<TextView
/>
</RelativeLayout>
</FrameLayout>
<ListView
android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="#111"
android:choiceMode="singleChoice"
android:divider="@color/gray_auth"
android:dividerHeight="2dp" />
</android.support.v4.widget.DrawerLayout>
我的第二个活动的 xml 布局:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ListView
>
</ListView>
</RelativeLayout>
我在第一个活动(在列表视图中)中从 onitemclicklistener 调用第二个活动。问题不在其余代码中,因为它运行良好。它通过在第一个活动中实现导航抽屉而崩溃。错误(在 UserProfileActivity 的第 143 行)在第二个 listView 的适配器中。
适配器是:
private class detailUserAdapter extends ArrayAdapter<String> {
private Context context;
private ArrayList<String> campi;
private ArrayList<String> dettagli;
public detailUserAdapter(Context context, ArrayList<String> campi,
ArrayList<String> dettagli) {
super(context, R.layout.myprofile_user_item_layout, campi);
this.context = context;
this.campi = campi;
this.dettagli = dettagli;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// First let's verify the convertView is not null
if (convertView == null) {
// This a new view we inflate the new layout
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(
R.layout.myprofile_user_item_layout, parent, false);
}
// Now we can fill the layout with the right values
TextView userCampo = (TextView) convertView
.findViewById(R.id.textViewUser);
userCampo.setText(campi.get(position));
TextView userDetail = (TextView) convertView
.findViewById(R.id.textViewUserDetail);
userDetail.setText(dettagli.get(position));
return convertView;
}
当存在 userDetail.setText(dettagli.get(position)) 时,错误就在行中。但是向量包含一个值并且文本视图正确存在。myprofile_user_item_layout 的完整代码是
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="15dp" >
<TextView
android:id="@+id/textViewUser"
android:layout_width="110dp"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:text="TextView" />
<TextView
android:id="@+id/textViewUserDetail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textViewUser"
android:layout_centerHorizontal="false"
android:layout_toRightOf="@+id/textViewUser"
android:text="TextView"
android:textColor="@color/red" />