我有一个名为＆＃34的应用程序; AppOne＆＃34;我已经制作了记录学生数据的内容提供者，为此我使用内容提供者来保存学生数据。我想在其他应用程序中检索这些数据。我怎么能这样做。
App One内容提供商： -
static final String PROVIDER_NAME = "com.example.provider.College";
static final String URL = "content://" + PROVIDER_NAME + "/students";
static final Uri CONTENT_URI = Uri.parse(URL);
static final String _ID = "_id";
static final String NAME = "name";
static final String GRADE = "grade";
private static HashMap<String, String> STUDENTS_PROJECTION_MAP;
static final int STUDENTS = 1;
static final int STUDENT_ID = 2;
static final UriMatcher uriMatcher;
static{
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
uriMatcher.addURI(PROVIDER_NAME, "students", STUDENTS);
uriMatcher.addURI(PROVIDER_NAME, "students/#", STUDENT_ID);
}
/**
* Database specific constant declarations
*/
private SQLiteDatabase db;
static final String DATABASE_NAME = "College";
static final String STUDENTS_TABLE_NAME = "students";
static final int DATABASE_VERSION = 1;
static final String CREATE_DB_TABLE =
" CREATE TABLE " + STUDENTS_TABLE_NAME +
" (_id INTEGER PRIMARY KEY AUTOINCREMENT, " +
" name TEXT NOT NULL, " +
" grade TEXT NOT NULL);";
/**
* Helper class that actually creates and manages
* the provider's underlying data repository.
*/
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_DB_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + STUDENTS_TABLE_NAME);
onCreate(db);
}
}
@Override
public boolean onCreate() {
Context context = getContext();
DatabaseHelper dbHelper = new DatabaseHelper(context);
/**
* Create a write able database which will trigger its
* creation if it doesn't already exist.
*/
db = dbHelper.getWritableDatabase();
return (db == null)? false:true;
}
@Override
public Uri insert(Uri uri, ContentValues values) {
/**
* Add a new student record
*/
long rowID = db.insert( STUDENTS_TABLE_NAME, "", values);
/**
* If record is added successfully
*/
if (rowID > 0)
{
Uri _uri = ContentUris.withAppendedId(CONTENT_URI, rowID);
getContext().getContentResolver().notifyChange(_uri, null);
return _uri;
}
throw new SQLException("Failed to add a record into " + uri);
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
qb.setTables(STUDENTS_TABLE_NAME);
switch (uriMatcher.match(uri)) {
case STUDENTS:
qb.setProjectionMap(STUDENTS_PROJECTION_MAP);
break;
case STUDENT_ID:
qb.appendWhere( _ID + "=" + uri.getPathSegments().get(1));
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
if (sortOrder == null || sortOrder == ""){
/**
* By default sort on student names
*/
sortOrder = NAME;
}
Cursor c = qb.query(db, projection, selection, selectionArgs,null, null, sortOrder);
/**
* register to watch a content URI for changes
*/
c.setNotificationUri(getContext().getContentResolver(), uri);
return c;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
int count = 0;
switch (uriMatcher.match(uri)){
case STUDENTS:
count = db.delete(STUDENTS_TABLE_NAME, selection, selectionArgs);
break;
case STUDENT_ID:
String id = uri.getPathSegments().get(1);
count = db.delete( STUDENTS_TABLE_NAME, _ID + " = " + id +
(!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : ""), selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
int count = 0;
switch (uriMatcher.match(uri)){
case STUDENTS:
count = db.update(STUDENTS_TABLE_NAME, values, selection, selectionArgs);
break;
case STUDENT_ID:
count = db.update(STUDENTS_TABLE_NAME, values, _ID + " = " + 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 String getType(Uri uri) {
switch (uriMatcher.match(uri)){
/**
* Get all student records
*/
case STUDENTS:
return "vnd.android.cursor.dir/vnd.example.students";
/**
* Get a particular student
*/
case STUDENT_ID:
return "vnd.android.cursor.item/vnd.example.students";
default:
throw new IllegalArgumentException("Unsupported URI: " + uri);
}
}
主要活动代码： -
m_Mobile = (EditText) findViewById(R.id.input_mobile);
m_Password = (EditText) findViewById(R.id.input_password);
m_Submmit = (Button) findViewById(R.id.submit);
m_Submmit.setOnClickListener(this);
m_GetData = (Button) findViewById(R.id.get);
m_GetData.setOnClickListener(this);
}
@Override
public void onClick(View view) {
if (view==m_Submmit){
s_szMobileNumer = m_Mobile.getText().toString().trim();
s_szPassword = m_Password.getText().toString().trim();
ContentValues values = new ContentValues();
values.put(MyContentProvider.NAME,s_szMobileNumer);
values.put(MyContentProvider.GRADE,s_szPassword);
Uri uri = getContentResolver().insert(MyContentProvider.CONTENT_URI,values);
Toast.makeText(getApplicationContext(),uri.toString(),Toast.LENGTH_LONG).show();
}if (view == m_GetData){
// Retrieve student records
String URL = MyContentProvider.URL;
Uri getdata = Uri.parse(URL);
Cursor c = managedQuery(getdata, null, null, null, "name");
if (c.moveToFirst()){
do {
Toast.makeText(this,
c.getString(c.getColumnIndex(MyContentProvider._ID)) +
", " + c.getString(c.getColumnIndex( MyContentProvider.NAME)) +
", " + c.getString(c.getColumnIndex( MyContentProvider.GRADE)),
Toast.LENGTH_SHORT).show();
Log.e(TAG, "Id:" + c.getString(c.getColumnIndex(MyContentProvider._ID)));
Log.e(TAG, "User Name:" + c.getString(c.getColumnIndex(MyContentProvider.NAME)));
Log.e(TAG, "Password::" + c.getString(c.getColumnIndex(MyContentProvider.GRADE)));
}
while (c.moveToNext());
}
}
}
在另一个应用程序中，我想检索所有学生记录和特定学生记录。