问题
I'm having an issue using a MatrixCursor
to populate my ListView
:
private void fillData() {
String[] menuCols = new String[] { "icon", "item", "price" };
int[] to = new int[] { R.id.icon, R.id.item, R.id.price };
MatrixCursor menuCursor = new MatrixCursor(menuCols);
startManagingCursor(menuCursor);
menuCursor.addRow(new Object[] { R.drawable.chicken_sandwich, "Chicken Sandwich", "$3.99" });
SimpleCursorAdapter menuItems = new SimpleCursorAdapter(
this, R.layout.menu_row, menuCursor, menuCols, to);
setListAdapter(menuItems);
}
Constructing the SimpleCursorAdapter
causes a crash. Even when I tried removing the icon the app still crashed. Here is my menu_row.xml
:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<ImageView
android:id="@+id/icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</ImageView>
<TextView
android:id="@+id/item"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/price"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
Edit: Here is the call stack at the time of the crash:
Thread [<3> main] (Suspended (exception RuntimeException))
ActivityThread.performLaunchActivity(ActivityThread$ActivityRecord, Intent) line: 2481
ActivityThread.handleLaunchActivity(ActivityThread$ActivityRecord, Intent) line: 2497
ActivityThread.access$2200(ActivityThread, ActivityThread$ActivityRecord, Intent) line: 119
ActivityThread$H.handleMessage(Message) line: 1848
ActivityThread$H(Handler).dispatchMessage(Message) line: 99
Looper.loop() line: 123
ActivityThread.main(String[]) line: 4338
Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]
Method.invoke(Object, Object...) line: 521
ZygoteInit$MethodAndArgsCaller.run() line: 860
ZygoteInit.main(String[]) line: 618
NativeStart.main(String[]) line: not available [native method]
SOLUTION:
I found the problem and the solution is in my answer below.
回答1:
Let's chalk this one up to inexperience with debugging Java using Eclipse.
Running the application in the debugger, I crashed with a RuntimeException. Clicking the very top element in the call stack gave me the list of Variables, at which I saw my Exception e.
The specific error was an InvalidArgument because my MatrixCursor did not have an _id column. Adding a column labeled _id fixed the problem and now everything works.
Thanks for making me look at the debugger again! Be comfortable with and knowledgeable about your tools!
来源:https://stackoverflow.com/questions/1882156/using-matrixcursor-and-simplecursoradapter-in-a-listview-with-text-and-images