我正在开发一个用户在运行时添加数据的项目。我正在使用cursorloader加载数据内容提供程序以将数据添加到数据库和customadapter以将数据设置为recyclerview。问题是每当用户向数据插入新数据时正在添加到数据库，但它没有在recyclerview中更新。
当用户输入数据时执行方法addDetails(View view)
public class AddLog extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor>{
TextView TotalAmount,Date;
EditText name,mobile,city,detailname,detailamount;
RecyclerView adddetailtolist;
DetailsAdapter adapter;
Intent returnback;
double totamount;
long logid;
String Debt = "Debt";
String Paid = "Paid";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_log);
Toolbar toolbar = (Toolbar)findViewById(R.id.addlogtoolbar);
setSupportActionBar(toolbar);
toolbar.setTitle("Add Log");
returnback = new Intent(this,MainActivity.class);
Intent intent = getIntent();
logid = intent.getExtras().getLong("ID");
TotalAmount = (TextView)findViewById(R.id.totalAmount);
Date = (TextView)findViewById(R.id.addlogDate);
name = (EditText)findViewById(R.id.AddName);
mobile = (EditText)findViewById(R.id.AddPhone);
city = (EditText)findViewById(R.id.Addcity);
detailname = (EditText)findViewById(R.id.Detailname);
detailamount = (EditText)findViewById(R.id.Detailamount);
adddetailtolist = (RecyclerView)findViewById(R.id.addloglist);
Date.setText(getDate());
getSupportLoaderManager().initLoader(2,null,this);
}
private String getDate()
{
Calendar calendar = Calendar.getInstance();
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("EEE,dd-MMM-yyyy");
String date = simpleDateFormat.format(calendar.getTime());
return date;
}
public void addDetails(View view)
{
String Name = detailname.getText().toString();
String Amount = detailamount.getText().toString();
String date = Date.getText().toString();
ContentValues contentValues = new ContentValues();
contentValues.put(DataProvider.Dname,Name);
contentValues.put(DataProvider.DCategory,Debt);
contentValues.put(DataProvider.Damount,Amount);
contentValues.put(DataProvider.Ddate,date);
contentValues.put(DataProvider.Per_In,logid);
getContentResolver().insert(DataProvider.ContentUri_Details,contentValues);
adapter.notifyDataSetChanged();
Toast.makeText(AddLog.this, DataProvider.Per_In, Toast.LENGTH_SHORT).show();
NumberFormat currency = changeamount();
TotalAmount.setText(currency.format(getAmount()));
}
private double getAmount()
{
ContentProviderClient client = getContentResolver().acquireContentProviderClient(DataProvider.ContentUri_Details);
SQLiteDatabase db = ((DataProvider)client.getLocalContentProvider()).sqLiteDatabase;
String query = "SELECT SUM(DAmount) FROM Details WHERE Per_In = "+logid;
Cursor cursor = db.rawQuery(query, null);
cursor.moveToFirst();
double amount = cursor.getDouble(0);
cursor.close();
client.release();
return amount;
}
public NumberFormat changeamount()
{
Locale locale = new Locale("en","IN");
NumberFormat currencyformat = NumberFormat.getCurrencyInstance(locale);
return currencyformat;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater menuinflate = getMenuInflater();
menuinflate.inflate(R.menu.addlogmenu,menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
switch (item.getItemId())
{
case R.id.done:
saveData();
}
return super.onOptionsItemSelected(item);
}
private void saveData()
{
String name1 = name.getText().toString();
String phone = mobile.getText().toString();
String address = city.getText().toString();
if (TextUtils.isEmpty(name1)||TextUtils.isEmpty(phone)||TextUtils.isEmpty(address))
{
if (TextUtils.isEmpty(name1))
{
name.setError("Feild can not be Empty");
}
else if (TextUtils.isEmpty(phone))
{
mobile.setError("Feild can not be Empty");
}
else if (TextUtils.isEmpty(address))
{
city.setError("Feild can not be Empty");
}
}
else
{
ContentValues values = new ContentValues();
values.put(DataProvider.Pname,name1);
values.put(DataProvider.Pphone,phone);
values.put(DataProvider.Paddress,address);
values.put(DataProvider.PCategory,"Debt");
values.put(DataProvider.Pamount,totamount);
String uri = DataProvider.ContentUri_Person+"/"+logid;
Uri uri1 = Uri.parse(uri);
getContentResolver().update(uri1,values,null,null);
startActivity(returnback);
finish();
}
}
@Override
public Loader<Cursor> onCreateLoader(final int id, Bundle args)
{
String _uri = DataProvider.ContentUri_Details+"/"+logid;
Uri uri = Uri.parse(_uri);
return new CursorLoader(this,uri,new String[]{DataProvider.Dname,DataProvider.Damount,DataProvider.Ddate},null,null,null);
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data)
{
adapter = new DetailsAdapter(this,data);
adddetailtolist.setAdapter(adapter);
adddetailtolist.setLayoutManager(new LinearLayoutManager(this));
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
}
}
自定义光标适配器：
public abstract class CursorRecyclerViewAdapter<VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> {
private Context mContext;
private Cursor mCursor;
private boolean mDataValid;
private int mRowIdColumn;
private DataSetObserver mDataSetObserver;
public CursorRecyclerViewAdapter(Context context, Cursor cursor) {
mContext = context;
mCursor = cursor;
mDataValid = cursor != null;
mRowIdColumn = mDataValid ? mCursor.getColumnIndex("_id") : -1;
mDataSetObserver = new NotifyingDataSetObserver();
if (mCursor != null) {
mCursor.registerDataSetObserver(mDataSetObserver);
}
}
public Cursor getCursor() {
return mCursor;
}
@Override
public int getItemCount() {
if (mDataValid && mCursor != null) {
return mCursor.getCount();
}
return 0;
}
@Override
public long getItemId(int position) {
if (mDataValid && mCursor != null && mCursor.moveToPosition(position)) {
return mCursor.getLong(mRowIdColumn);
}
return 0;
}
@Override
public void setHasStableIds(boolean hasStableIds) {
super.setHasStableIds(true);
}
public abstract void onBindViewHolder(VH viewHolder, Cursor cursor);
@Override
public void onBindViewHolder(VH viewHolder, int position) {
if (!mDataValid) {
throw new IllegalStateException("this should only be called when the cursor is valid");
}
if (!mCursor.moveToPosition(position)) {
throw new IllegalStateException("couldn't move cursor to position " + position);
}
onBindViewHolder(viewHolder, mCursor);
}
/**
* Change the underlying cursor to a new cursor. If there is an existing cursor it will be
* closed.
*/
public void changeCursor(Cursor cursor) {
Cursor old = swapCursor(cursor);
if (old != null) {
old.close();
}
}
/**
* Swap in a new Cursor, returning the old Cursor. Unlike
* {@link #changeCursor(Cursor)}, the returned old Cursor is <em>not</em>
* closed.
*/
public Cursor swapCursor(Cursor newCursor) {
if (newCursor == mCursor) {
return null;
}
final Cursor oldCursor = mCursor;
if (oldCursor != null && mDataSetObserver != null) {
oldCursor.unregisterDataSetObserver(mDataSetObserver);
}
mCursor = newCursor;
if (mCursor != null) {
if (mDataSetObserver != null) {
mCursor.registerDataSetObserver(mDataSetObserver);
}
mRowIdColumn = newCursor.getColumnIndexOrThrow("_id");
mDataValid = true;
notifyDataSetChanged();
} else {
mRowIdColumn = -1;
mDataValid = false;
notifyDataSetChanged();
//There is no notifyDataSetInvalidated() method in RecyclerView.Adapter
}
return oldCursor;
}
private class NotifyingDataSetObserver extends DataSetObserver {
@Override
public void onChanged() {
super.onChanged();
mDataValid = true;
notifyDataSetChanged();
}
@Override
public void onInvalidated() {
super.onInvalidated();
mDataValid = false;
notifyDataSetChanged();
//There is no notifyDataSetInvalidated() method in RecyclerView.Adapter
}
}
}
适配器类
public class DetailsAdapter extends CursorRecyclerViewAdapter<DetailsAdapter.View_Holder>
{
public DetailsAdapter(Context context, Cursor cursor) {
super(context, cursor);
}
public static class View_Holder extends RecyclerView.ViewHolder
{
TextView mName,mAmount,mDate;
public View_Holder(View itemView)
{
super(itemView);
mName = (TextView)itemView.findViewById(R.id.DetailName);
mAmount = (TextView)itemView.findViewById(R.id.DetailAmount);
mDate = (TextView)itemView.findViewById(R.id.DetailDate);
}
}
@Override
public DetailsAdapter.View_Holder onCreateViewHolder(ViewGroup parent, int viewType)
{
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.addloglistlayout,parent,false);
View_Holder viewHolder = new View_Holder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(DetailsAdapter.View_Holder viewHolder, Cursor cursor)
{
Details details = Details.from(cursor);
viewHolder.mName.setText(details.getName());
viewHolder.mAmount.setText(String.valueOf(details.getAmount()));
viewHolder.mDate.setText(details.getDate());
}
}
内容提供商：
public class DataProvider extends ContentProvider
{
static final String ProviderName = "com.example.mrudu.accounts.provider";
static final String URLPerson = "content://"+ProviderName+"/Person_Detail";
static final String URLDetails = "content://"+ProviderName+"/Details";
static final Uri ContentUri_Person = Uri.parse(URLPerson);
static final Uri ContentUri_Details = Uri.parse(URLDetails);
//Tables
private static String PTableName = "Person_Detail";
private static String DTableName = "Details";
public static long insertId = 0;
public static long logid = 0;
//Person_Detail Coloumns
public static String PID = "_Id";
public static String Pname = "PName";
public static String Pphone = "PMobile";
public static String Paddress = "PCity";
public static String PCategory = "PCategory";
public static String Pamount = "PAmount";
//Details coloumn
public static String DID = "_Id";
public static String Dname = "DName";
public static String Damount = "DAmount";
public static String Ddate = "DDate";
public static String DCategory = "DCategory";
public static String Per_In = "Per_In";
private static final int Person = 1;
private static final int Person_ID = 2;
private static final int Details = 3;
private static final int Details_Id = 4;
static UriMatcher uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
static
{
uriMatcher.addURI(ProviderName,PTableName,Person);
uriMatcher.addURI(ProviderName,PTableName+"/#",Person_ID);
uriMatcher.addURI(ProviderName,DTableName,Details);
uriMatcher.addURI(ProviderName,DTableName+"/#",Details_Id);
}
public static SQLiteDatabase sqLiteDatabase;
private static String Databasename = "Accounts";
private static int DatabaseVersion = 1;
private class DatabaseHelper extends SQLiteOpenHelper
{
public DatabaseHelper(Context context)
{
super(context, Databasename, null, DatabaseVersion);
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase)
{
String Create_Person = " Create Table "+PTableName+"("+PID+" INTEGER PRIMARYKEY ,"+Pname+" TEXT ,"+Pphone+" TEXT ,"+Paddress+" TEXT ,"+PCategory+" TEXT ,"+Pamount+" REAL"+")";
String Create_Details = " Create Table "+DTableName+"("+DID+" INTEGER PRIMARYKEY ,"+Dname+" TEXT ,"+DCategory+" TEXT ,"+Damount+" REAl ,"+Ddate+" TEXT ,"+Per_In+" INTEGER )";
sqLiteDatabase.execSQL(Create_Person);
sqLiteDatabase.execSQL(Create_Details);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1)
{
sqLiteDatabase.execSQL("Drop TABLE if exists"+PTableName);
sqLiteDatabase.execSQL("Drop TABLE if exists"+DTableName);
onCreate(sqLiteDatabase);
}
}
@Override
public boolean onCreate()
{
Context context = getContext();
DatabaseHelper databaseHelper = new DatabaseHelper(context);
sqLiteDatabase = databaseHelper.getWritableDatabase();
return (sqLiteDatabase==null)?false:true;
}
@Override
public Uri insert(Uri uri, ContentValues values)
{
switch (uriMatcher.match(uri))
{
case Person:
long rowId = sqLiteDatabase.insert(PTableName,null,values);
insertId = rowId;
if (rowId>0)
{
Uri _uri = ContentUris.withAppendedId(ContentUri_Person,rowId);
getContext().getContentResolver().notifyChange(_uri,null);
return _uri;
}
break;
case Details:
long rowId1 = sqLiteDatabase.insert(DTableName,null,values);
if (rowId1>0)
{
Uri _uri = ContentUris.withAppendedId(ContentUri_Details,rowId1);
getContext().getContentResolver().notifyChange(_uri,null);
return _uri;
}
break;
}
return null;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder)
{
SQLiteQueryBuilder sqLiteQueryBuilder = new SQLiteQueryBuilder();
switch (uriMatcher.match(uri))
{
case Person_ID:
sqLiteQueryBuilder.setTables(PTableName);
sqLiteQueryBuilder.appendWhere(PID+ "="+ uri.getPathSegments().get(1));
break;
case Person:
sqLiteQueryBuilder.setTables(PTableName);
break;
case Details_Id:
sqLiteQueryBuilder.setTables(DTableName);
sqLiteQueryBuilder.appendWhere(Per_In +"="+ uri.getPathSegments().get(1));
break;
case Details:
sqLiteQueryBuilder.setTables(DTableName);
break;
default:
throw new UnsupportedOperationException("Not yet implemented");
}
Cursor cursor = sqLiteQueryBuilder.query(sqLiteDatabase,projection,selection,selectionArgs,null,null,"_ID");
cursor.setNotificationUri(getContext().getContentResolver(),uri);
return cursor;
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs)
{
int count = 0;
switch (uriMatcher.match(uri))
{
case Person:
count = sqLiteDatabase.update(PTableName,values,selection,selectionArgs);
break;
case Person_ID:
count = sqLiteDatabase.update(PTableName,values,PID+" = "+uri.getPathSegments().get(1)+(!TextUtils.isEmpty(selection)?" AND (" + selection + ')':""),selectionArgs);
break;
case Details:
count = sqLiteDatabase.update(DTableName,values,selection,selectionArgs);
break;
case Details_Id:
count = sqLiteDatabase.update(DTableName,values,Per_In+" = "+uri.getPathSegments().get(1)+(!TextUtils.isEmpty(selection)?" AND (" + selection + ')':""),selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri );
}
getContext().getContentResolver().notifyChange(uri,null);
return count;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
// Implement this to handle requests to delete one or more rows.
throw new UnsupportedOperationException("Not yet implemented");
}
@Override
public String getType(Uri uri) {
// TODO: Implement this to handle requests for the MIME type of the data
// at the given URI.
throw new UnsupportedOperationException("Not yet implemented");
}
}
谢谢
答案 0 :(得分：0)
问题出在旁边。在ContentProvider中更新数据期间，您发送通知：
getContext().getContentResolver().notifyChange(uri,null);
但你没有听取这些改变。请在此处查看更多信息：How do CursorLoader automatically updates the view even if the app is inactive?