我已经构建了自己的内容提供程序，并且我遇到了一个需要执行查询并包含限制参数的实例。
对managedQuery的方法调用不包含这个参数，因此我认为没有办法实现这个w / o以某种方式覆盖managedQuery方法？
我在我的内容提供程序中创建了第二个查询方法，它接受了一个额外的参数，即限制参数，但我认为我不能让managedQuery方法调用我的内容提供程序的这个自定义查询方法。
最好的方法是什么？
供参考，这是我的内容提供者类...... 包com.isi.sa;
import java.text.DateFormat;
import java.util.Date;
import java.util.HashMap;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.text.TextUtils;
import android.util.Log;
import com.isi.sa.SATest.Questions;
import com.isi.sa.SATest.Scores;
public class SAContentProvider extends ContentProvider {
private static final String TAG = "SAProvider";
private static final String DATABASE_NAME = "sa.db";
private static final int DATABASE_VERSION = 1;
private static final String QUESTIONS_TABLE_NAME = "questions";
private static final String SCORES_TABLE_NAME = "scores";
private static HashMap<String, String> sQuestionsProjectionMap;
private static HashMap<String, String> sScoresProjectionMap;
private static final int QUESTIONS = 1;
private static final int QUESTION_ID = 2;
private static final int SCORES = 3;
private static final int SCORE_ID = 4;
private DatabaseHelper mOpenHelper;
private static final UriMatcher sUriMatcher;
@Override
public boolean onCreate() {
mOpenHelper = new DatabaseHelper(getContext());
return true;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
switch (sUriMatcher.match(uri)){
case QUESTIONS:
qb.setTables(QUESTIONS_TABLE_NAME);
qb.setProjectionMap(sQuestionsProjectionMap);
if (TextUtils.isEmpty(sortOrder)) sortOrder = Questions.DEFAULT_SORT_ORDER;
break;
case QUESTION_ID:
qb.setTables(QUESTIONS_TABLE_NAME);
qb.setProjectionMap(sQuestionsProjectionMap);
qb.appendWhere(Questions._ID + "=" + uri.getPathSegments().get(1));
if (TextUtils.isEmpty(sortOrder)) sortOrder = Questions.DEFAULT_SORT_ORDER;
break;
case SCORES:
qb.setTables(SCORES_TABLE_NAME);
qb.setProjectionMap(sScoresProjectionMap);
if (TextUtils.isEmpty(sortOrder)) sortOrder = Scores.DEFAULT_SORT_ORDER;
break;
case SCORE_ID:
qb.setTables(SCORES_TABLE_NAME);
qb.setProjectionMap(sScoresProjectionMap);
qb.appendWhere(Scores._ID + "=" + uri.getPathSegments().get(1));
if (TextUtils.isEmpty(sortOrder)) sortOrder = Scores.DEFAULT_SORT_ORDER;
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
// Get the database and run the query
SQLiteDatabase db = mOpenHelper.getReadableDatabase();
Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, sortOrder);
// Tell the cursor what uri to watch, so it knows when its source data changes
c.setNotificationUri(getContext().getContentResolver(), uri);
return c;
}
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder, String limit) {
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
switch (sUriMatcher.match(uri)){
case QUESTIONS:
qb.setTables(QUESTIONS_TABLE_NAME);
qb.setProjectionMap(sQuestionsProjectionMap);
if (TextUtils.isEmpty(sortOrder)) sortOrder = Questions.DEFAULT_SORT_ORDER;
break;
case QUESTION_ID:
qb.setTables(QUESTIONS_TABLE_NAME);
qb.setProjectionMap(sQuestionsProjectionMap);
qb.appendWhere(Questions._ID + "=" + uri.getPathSegments().get(1));
if (TextUtils.isEmpty(sortOrder)) sortOrder = Questions.DEFAULT_SORT_ORDER;
break;
case SCORES:
qb.setTables(SCORES_TABLE_NAME);
qb.setProjectionMap(sScoresProjectionMap);
if (TextUtils.isEmpty(sortOrder)) sortOrder = Scores.DEFAULT_SORT_ORDER;
break;
case SCORE_ID:
qb.setTables(SCORES_TABLE_NAME);
qb.setProjectionMap(sScoresProjectionMap);
qb.appendWhere(Scores._ID + "=" + uri.getPathSegments().get(1));
if (TextUtils.isEmpty(sortOrder)) sortOrder = Scores.DEFAULT_SORT_ORDER;
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
// Get the database and run the query
SQLiteDatabase db = mOpenHelper.getReadableDatabase();
Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, sortOrder, limit);
// Tell the cursor what uri to watch, so it knows when its source data changes
c.setNotificationUri(getContext().getContentResolver(), uri);
return c;
}
@Override
public Uri insert(Uri uri, ContentValues initialValues) {
ContentValues values;
SQLiteDatabase db;
long rowId;
if (sUriMatcher.match(uri) != QUESTIONS && sUriMatcher.match(uri) != SCORES) {
throw new IllegalArgumentException("Unknown URI " + uri);
}
if (initialValues != null){
values = new ContentValues(initialValues);
}
else{
values = new ContentValues();
}
switch (sUriMatcher.match(uri)){
case QUESTIONS:
if (values.containsKey(Questions.QUESTION) == false) values.put(Questions.QUESTION, "");
if (values.containsKey(Questions.QUESTION) == false) values.put(Questions.ANSWER, -1);
if (values.containsKey(Questions.OPTION1) == false) values.put(Questions.OPTION1, "");
if (values.containsKey(Questions.OPTION2) == false) values.put(Questions.OPTION2, "");
if (values.containsKey(Questions.OPTION3) == false) values.put(Questions.OPTION3, "");
if (values.containsKey(Questions.OPTION4) == false) values.put(Questions.OPTION4, "");
if (values.containsKey(Questions.OPTION5) == false) values.put(Questions.OPTION5, "");
if (values.containsKey(Questions.OPTION6) == false) values.put(Questions.OPTION6, "");
if (values.containsKey(Questions.OPTION7) == false) values.put(Questions.OPTION7, "");
if (values.containsKey(Questions.OPTION8) == false) values.put(Questions.OPTION8, "");
if (values.containsKey(Questions.OPTION9) == false) values.put(Questions.OPTION9, "");
if (values.containsKey(Questions.OPTION10) == false) values.put(Questions.OPTION10, "");
if (values.get(Questions.QUESTION).toString().length() > 0 &&
values.get(Questions.ANSWER).toString() != "-1" &&
values.get(Questions.OPTION1).toString().length() > 0){
db = mOpenHelper.getWritableDatabase();
rowId = db.insert(QUESTIONS_TABLE_NAME, Questions.QUESTION, values);
if (rowId > 0) {
Uri noteUri = ContentUris.withAppendedId(Questions.CONTENT_URI, rowId);
getContext().getContentResolver().notifyChange(noteUri, null);
return noteUri;
}
}
break;
case SCORES:
if (values.containsKey(Scores.SCORE) == false) values.put(Scores.SCORE, -1);
if (values.containsKey(Scores.DATE_CREATED) == false) values.put(Scores.DATE_CREATED, DateFormat.getDateTimeInstance().format(new Date()));
if (values.get(Scores.SCORE).toString() != "-1"){
db = mOpenHelper.getWritableDatabase();
rowId = db.insert(SCORES_TABLE_NAME, Scores.SCORE, values);
if (rowId > 0) {
Uri noteUri = ContentUris.withAppendedId(Questions.CONTENT_URI, rowId);
getContext().getContentResolver().notifyChange(noteUri, null);
return noteUri;
}
}
break;
}
throw new SQLException("Failed to insert row into " + uri);
}
@Override
public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
int count;
switch(sUriMatcher.match(uri)){
case QUESTIONS:
count = db.update(QUESTIONS_TABLE_NAME, values, where, whereArgs);
break;
case QUESTION_ID:
String questionId = uri.getPathSegments().get(1);
count = db.update(QUESTIONS_TABLE_NAME, values, Questions._ID + "=" + questionId
+ (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
break;
case SCORES:
count = db.update(SCORES_TABLE_NAME, values, where, whereArgs);
break;
case SCORE_ID:
String scoreId = uri.getPathSegments().get(1);
count = db.update(SCORES_TABLE_NAME, values, Scores._ID + "=" + scoreId
+ (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
@Override
public int delete(Uri uri, String where, String[] whereArgs) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
int count;
switch(sUriMatcher.match(uri)){
case QUESTIONS:
count = db.delete(QUESTIONS_TABLE_NAME, where, whereArgs);
break;
case QUESTION_ID:
String questionId = uri.getPathSegments().get(1);
count = db.delete(QUESTIONS_TABLE_NAME, Questions._ID + "=" + questionId
+ (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
break;
case SCORES:
count = db.delete(SCORES_TABLE_NAME, where, whereArgs);
break;
case SCORE_ID:
String scoreId = uri.getPathSegments().get(1);
count = db.delete(SCORES_TABLE_NAME, Scores._ID + "=" + scoreId
+ (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
@Override
public String getType(Uri uri) {
switch (sUriMatcher.match(uri)) {
case QUESTIONS:
return Questions.CONTENT_TYPE;
case QUESTION_ID:
return Questions.CONTENT_ITEM_TYPE;
case SCORES:
return Scores.CONTENT_TYPE;
case SCORE_ID:
return Scores.CONTENT_ITEM_TYPE;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
}
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE questions ("
+ "_id INTEGER PRIMARY KEY AUTOINCREMENT,"
+ "question TEXT,"
+ "answer INTEGER,"
+ "option1 TEXT,"
+ "option2 TEXT,"
+ "option3 TEXT,"
+ "option4 TEXT,"
+ "option5 TEXT,"
+ "option6 TEXT,"
+ "option7 TEXT,"
+ "option8 TEXT,"
+ "option9 TEXT,"
+ "option10 TEXT);");
db.execSQL("CREATE TABLE scores ("
+ "_id INTEGER PRIMARY KEY AUTOINCREMENT,"
+ "score NUMERIC,"
+ "date_created TEXT);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
}
}
static {
sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
sUriMatcher.addURI(SATest.AUTHORITY, "questions", QUESTIONS);
sUriMatcher.addURI(SATest.AUTHORITY, "questions/#", QUESTION_ID);
sUriMatcher.addURI(SATest.AUTHORITY, "scores", SCORES);
sUriMatcher.addURI(SATest.AUTHORITY, "scores/#", SCORE_ID);
sQuestionsProjectionMap = new HashMap<String, String>();
sQuestionsProjectionMap.put(Questions._ID, Questions._ID);
sQuestionsProjectionMap.put(Questions.QUESTION, Questions.QUESTION);
sQuestionsProjectionMap.put(Questions.ANSWER, Questions.ANSWER);
sQuestionsProjectionMap.put(Questions.OPTION1, Questions.OPTION1);
sQuestionsProjectionMap.put(Questions.OPTION2, Questions.OPTION2);
sQuestionsProjectionMap.put(Questions.OPTION3, Questions.OPTION3);
sQuestionsProjectionMap.put(Questions.OPTION4, Questions.OPTION4);
sQuestionsProjectionMap.put(Questions.OPTION5, Questions.OPTION5);
sQuestionsProjectionMap.put(Questions.OPTION6, Questions.OPTION6);
sQuestionsProjectionMap.put(Questions.OPTION7, Questions.OPTION7);
sQuestionsProjectionMap.put(Questions.OPTION8, Questions.OPTION8);
sQuestionsProjectionMap.put(Questions.OPTION9, Questions.OPTION9);
sQuestionsProjectionMap.put(Questions.OPTION10, Questions.OPTION10);
sScoresProjectionMap = new HashMap<String, String>();
sScoresProjectionMap.put(Scores._ID, Scores._ID);
sScoresProjectionMap.put(Scores.SCORE, Scores.SCORE);
sScoresProjectionMap.put(Scores.DATE_CREATED, Scores.DATE_CREATED);
}
}
答案 0 :(得分：3)
如果内容提供商的消费者与内容提供商本身位于同一应用程序中，请不要使用内容提供商 - 直接进入数据库。 ContentProvider专为进程间通信而设计，因此会增加开销并限制您的API。