我的数据库更新后，无法通知适配器更改。我必须退出活动并返回以查看列表已更新。我已经尝试了一些我已经阅读但没有运气的想法，所以我想我会发布我的代码，希望有人可以看到这个bug所在的位置。谢谢！
//public class ViolationsList extends ListActivity {
public class ViolationsList extends Activity {
// protected ListView violationsList;
private static final String TAG = "MyActivity";
protected static String violation = "";
protected String graph_or_fql;
protected String myFriendID = "not set";
protected String picture = "";
protected String response = "";
protected String name = "";
boolean violatorSelected;
long friendId = 0;
private Cursor cursor=null;
//this is the array list for the custom violations from the database
private ArrayList<String> myCustomsArrayList = new ArrayList<String>();
//string array for custom violations
private String[] customViols;
//array list for building your three arrays into one array
private ArrayList<String> violationsCompArray = new ArrayList<String>();
String[] violations1;
String[] violations2;
ListView list;
private SpecialAdapter adapter;
//the view holder for the listview
static class ViewHolder {
TextView text;
}
//
private class SpecialAdapter extends BaseAdapter {
//Defining the background color of rows. The row will alternate between green light and green dark.
private int[] colors = new int[] { 0xff000000, 0xff888888, 0xffCCCCCC };
private LayoutInflater mInflater;
Typeface font1 = Typeface.createFromAsset(getAssets(), "fonts/Colossalis-Bold.ttf");
Typeface font2 = Typeface.createFromAsset(getAssets(), "fonts/helveticaneue.ttf");
//The variable that will hold our text data to be tied to list.
//private String[] data;
private ArrayList data = new ArrayList();
//public SpecialAdapter(Context context, String[] items) {
public SpecialAdapter(Context context, ArrayList items) {
mInflater = LayoutInflater.from(context);
this.data = items;
}
@Override
public int getCount() {
//return data.length;
return data.size();
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public void notifyDataSetChanged() {
// TODO Auto-generated method stub
super.notifyDataSetChanged();
}
//A view to hold each row in the list
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// A ViewHolder keeps references to children views to avoid unneccessary calls
// to findViewById() on each row.
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.row, null);
holder = new ViewHolder();
holder.text = (TextView) convertView.findViewById(R.id.headline);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
// Bind the data efficiently with the holder.
holder.text.setText((CharSequence) data.get(position));
//Set the background color of the holder
int colorPos = position % colors.length;
if ((holder.text.getText().toString().equals("ORIGINALS")) || (holder.text.getText().toString().equals("CUSTOM"))) {
Log.v(TAG, holder.text.getText().toString());
colorPos=1;
holder.text.setTypeface(font1);
//holder.text.setTextColor(Color.parseColor("#000000"));
} else if ("Make your own".equals(holder.text.getText().toString())) {
Log.v(TAG, holder.text.getText().toString());
colorPos=2;
}else {
colorPos=0;
holder.text.setTypeface(font2);
}
convertView.setBackgroundColor(colors[colorPos]);
return convertView;
}
}
////code for the custom violations database
private void insertCustom(String newViolation) {
DatabaseHelper databaseHelper = new DatabaseHelper(this);
SQLiteDatabase db = databaseHelper.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(DatabaseHelper.TITLE, newViolation);
db.insert("customViolations", DatabaseHelper.TITLE, cv);
cursor = db.query("customViolations",null, null, null, null, null, null);
startManagingCursor(cursor);
Log.v(TAG, "cursor data = " + cursor.toString());
cursor.requery();
db.close();
updateData();
adapter.notifyDataSetChanged();
}
private void DeleteCustom(String newViolation)
{
DatabaseHelper databaseHelper = new DatabaseHelper(this);
SQLiteDatabase db = databaseHelper.getWritableDatabase();
db.delete("customViolations", "myViolation" + "=?", new String[] { violation });
Log.v(TAG, violation);
db.close();
Log.v(TAG, "delete your custom violation");
cursor.requery();
updateData();
adapter.notifyDataSetChanged();
}
/////code to log cursor info KEEP FOR TESTING!!!!
public void logCursorInfo(Cursor cursor1) {
Log.i(TAG, "*** Cursor Begin *** " + " Results:" + cursor1.getCount() + " Columns: " + cursor1.getColumnCount());
//print column names
String rowHeaders = "|| ";
for (int i = 0; i < cursor1.getColumnCount(); i++) {
rowHeaders = rowHeaders.concat(cursor1.getColumnName(i) + " || ");
}
//print records
cursor1.moveToFirst();
while (cursor1.isAfterLast() == false) {
String rowResults = "|| ";
for (int i = 0; i < cursor1.getColumnCount(); i++) {
rowResults = rowResults.concat(cursor1.getString(i) + " || ");
}
Log.i(TAG, "Row " + cursor1.getPosition() + ": " + rowResults);
cursor1.moveToNext();
}
Log.i(TAG, "*** Cursor End ***");
}
///code to bring up text entry alert dialog
public void enterText() {
//insert dialog builder
AlertDialog.Builder alert = new AlertDialog.Builder(this);
String Title = getResources().getString(R.string.dialogTitle);
alert.setTitle(Title);
//alert.setMessage("Message");
// Set an EditText view to get user input
final EditText input = new EditText(this);
int maxLength = 60;
InputFilter[] FilterArray = new InputFilter[1];
FilterArray[0] = new InputFilter.LengthFilter(maxLength);
input.setFilters(FilterArray);
alert.setView(input);
alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
Editable value = input.getText();
// Do something with value!
insertCustom(value.toString());
cursor.requery();
}
});
alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
// Canceled.
}
});
alert.show();
}
///code to bring up text entry alert dialog
public void editYourViolation() {
//insert dialog builder
AlertDialog.Builder yourEdit = new AlertDialog.Builder(this);
String Title = getResources().getString(R.string.customdialogTitle);
yourEdit.setTitle(Title);
yourEdit.setPositiveButton("Use", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
// Do something with value!
createViolation();
}
});
yourEdit.setNegativeButton("Delete", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
// Canceled.
DeleteCustom(violation);
}
});
yourEdit.show();
}
///create the violation
public void createViolation() {
Intent myIntent = new Intent(getApplicationContext(),
Selection.class);
myIntent.putExtra("friendId", friendId);
myIntent.putExtra("name", name);
myIntent.putExtra("picture", picture);
myIntent.putExtra("violation", violation);
myIntent.putExtra("violatorSelected", violatorSelected);
startActivity(myIntent);
}
public void querydatabase() {
DatabaseHelper databaseHelper = new DatabaseHelper(this);
SQLiteDatabase db = databaseHelper.getWritableDatabase();
cursor = db.query("customViolations",null, null, null, null, null, null);
}
public void populateArray() {
cursor.moveToFirst();
while(!cursor.isAfterLast()) {
myCustomsArrayList.add(cursor.getString(cursor.getColumnIndex(DatabaseHelper.TITLE)));
cursor.moveToNext();
}
customViols = (String[]) myCustomsArrayList.toArray(new String[myCustomsArrayList.size()]);
}
private void updateData() {
querydatabase();
populateArray();
for(String i : violations1)
{
violationsCompArray.add(i);
}
//these are your custom violations
for(String z : customViols)
{
violationsCompArray.add(z);
}
//original violations list
for(String s : violations2)
{
violationsCompArray.add(s);
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle extras = getIntent().getExtras();
response = extras.getString("API_RESPONSE");
graph_or_fql = extras.getString("METHOD");
friendId = extras.getLong("friendId");
name = extras.getString("name");
picture = extras.getString("picture");
violatorSelected = extras.getBoolean("violatorSelected");
Log.v(TAG, "violations list created");
setContentView(R.layout.violations_list);
violations1 = getResources().getStringArray(
R.array.violations_array1);
violations2 = getResources().getStringArray(
R.array.violations_array2);
ListView list = (ListView) findViewById(R.id.violations_list);
list.setTextFilterEnabled(true);
//set up the database connection and cursor for the custom violations
updateData();
SpecialAdapter adapter = new SpecialAdapter(this, violationsCompArray);
list.setAdapter(adapter);
///new onItemClickListener
list.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView parent, View view,
int position, long id) {
for(String i : customViols)
{
Log.v(TAG, i);
}
String text = (String) ((TextView) view).getText();
violation = text;
//the make your own value will launch the text editor
if ("Make your own".equals(violation)) {
Log.v(TAG, "create the code for Make your own screen");
enterText();
//these values are section headers and should have no selection effect
}else if("ORIGINALS".equals(violation) || "CUSTOM".equals(violation)) {
Toast.makeText(getApplicationContext(), violation,
Toast.LENGTH_SHORT).show();
//test to see if the violation is from the custom violations list
}else if(Arrays.asList(customViols).contains(violation)) {
editYourViolation();
//use one of the originals
}else {
createViolation();
}
}
});
}
}
答案 0 :(得分：3)
在onCreate中，您将适配器定义为：
SpecialAdapter adapter = new SpecialAdapter(this, violationsCompArray);
但随后在其他地方你引用了同名的私有成员变量
private SpecialAdapter adapter;
非常需要解决这个问题，你只需要将onCreate中的行更改为：
adapter = new SpecialAdapter(this, violationsCompArray);
这样它引用的是类成员变量，而不是你正在创建的本地变量。