我正在研究网格视图。我需要使用 simplecursoradapter 使 gridview 连接到 sqlite。
但是，这段代码出错了
threadid=1; thread exiting with uncatught exception
让我先向您展示我的代码。
Wishlist.java
public class Wishlist extends Activity {
SQLiteConnector sqlCon;
private CustomWishlistsAdapter custAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.wishlist);
GridView gv = (GridView)findViewById(R.id.gridview);
Cursor c = managedQuery(????, null, null, null, Wishlists.NAME);
String[] from = new String[] { Wishlists.NAME, Wishlists.NOTE };
int[] to = new int[] { R.id.name };
custAdapter = new CustomWishlistsAdapter(this,
R.layout.wishlist_item, c, from, to);
gv.setAdapter(custAdapter);
}
@Override
protected void onResume() {
super.onResume();
new GetItems().execute((Object[]) null);
}
//@SuppressWarnings("deprecation")
@Override
protected void onStop() {
Cursor cursor = custAdapter.getCursor();
if (cursor != null)
cursor.deactivate();
custAdapter.changeCursor(null);
super.onStop();
}
private class GetItems extends AsyncTask<Object, Object, Cursor> {
SQLiteConnector dbConnector = new SQLiteConnector(Wishlist.this);
@Override
protected Cursor doInBackground(Object... params) {
return dbConnector.getAllWishlists();
}
@Override
protected void onPostExecute(Cursor result) {
custAdapter.changeCursor(result);
}
}
}
在上面的代码中，我应该在我的情况下放什么？(URI)
Cursor c = managedQuery(????, null, null, null, Wishlists.NAME);
这是简单的光标适配器类代码.. CustomWishlistAdapter.java
public class CustomWishlistsAdapter extends SimpleCursorAdapter {
EditText txtName;
EditText txtDesc;
EditText txtCreatedAt;
Button btnSave;
Button btnDelete;
String pid;
private int layout;
private ImageButton editBtn;
private ImageButton delBtn;
LayoutInflater inflator;
public CustomWishlistsAdapter(Context context, int layout, Cursor c,String[] from, int[] to) {
super(context, layout, c, from, to,0);
this.layout = layout;
inflator= LayoutInflater.from(context);
}
public View newView(Context context, Cursor cursor, ViewGroup parent) {
View v = inflator.inflate(layout, parent, false);
return v;
}
@Override
public void bindView(View v, final Context context, Cursor c) {
final int id = c.getInt(c.getColumnIndex(Wishlists.ID));
final String name = c.getString(c.getColumnIndex(Wishlists.NAME));
final String note = c.getString(c.getColumnIndex(Wishlists.NOTE));
final byte[] image = c.getBlob(c.getColumnIndex(Wishlists.IMAGE));
ImageView iv = (ImageView) v.findViewById(R.id.inputphoto);
// Change Image file to Byte Array
if (image != null) {
if (image.length > 3) {
iv.setImageBitmap(BitmapFactory.decodeByteArray(image, 0,image.length));
}
}
TextView tname = (TextView) v.findViewById(R.id.name);
tname.setText(name);
final SQLiteConnector sqlCon = new SQLiteConnector(context);
editBtn=(ImageButton) v.findViewById(R.id.edit_btn);
editBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent=new Intent(context,AddEditWishlists.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra("id", id);
intent.putExtra("name", name);
intent.putExtra("note", note);
intent.putExtra("blob", image);
context.startActivity(intent);
}
});
// Delete Product
delBtn=(ImageButton) v.findViewById(R.id.del_btn);
delBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
sqlCon.deleteWishlist(id);
Intent intent=new Intent(context,MyWishlistsActivity.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);
}
});
v.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent=new Intent(context,ViewWishlist.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra("id", id);
intent.putExtra("name", name);
intent.putExtra("note", note);
intent.putExtra("blob", image);
context.startActivity(intent);
}
});
}
}
记录猫输出
05-24 13:59:57.940: W/dalvikvm(5701): threadid=1: thread exiting with uncaught exception (group=0x40a4d1f8)
05-24 13:59:57.950: E/AndroidRuntime(5701): FATAL EXCEPTION: main
05-24 13:59:57.950: E/AndroidRuntime(5701): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.philips/com.example.philips.Wishlist}: java.lang.NullPointerException
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1978)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2003)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.ActivityThread.access$600(ActivityThread.java:123)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1169)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.os.Handler.dispatchMessage(Handler.java:99)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.os.Looper.loop(Looper.java:137)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.ActivityThread.main(ActivityThread.java:4446)
05-24 13:59:57.950: E/AndroidRuntime(5701): at java.lang.reflect.Method.invokeNative(Native Method)
05-24 13:59:57.950: E/AndroidRuntime(5701): at java.lang.reflect.Method.invoke(Method.java:511)
05-24 13:59:57.950: E/AndroidRuntime(5701): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
05-24 13:59:57.950: E/AndroidRuntime(5701): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
05-24 13:59:57.950: E/AndroidRuntime(5701): at dalvik.system.NativeStart.main(Native Method)
05-24 13:59:57.950: E/AndroidRuntime(5701): Caused by: java.lang.NullPointerException
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.content.ContentResolver.acquireProvider(ContentResolver.java:913)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.content.ContentResolver.query(ContentResolver.java:305)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.Activity.managedQuery(Activity.java:1706)
05-24 13:59:57.950: E/AndroidRuntime(5701): at com.example.philips.Wishlist.onCreate(Wishlist.java:24)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.Activity.performCreate(Activity.java:4465)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
05-24 13:59:57.950: E/AndroidRuntime(5701): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1942)