創建Contentprovider:
1. 創建一個provider----ExampleContentProvider
a. 設計authority b. 設計path c.處理content URI IDs d.Content URI patterns
)
定義MIME Types(One of the required methods that you must implement for any provider.A method that you're expected to implement if your provider offers files.)
package com.hualu.contentprovider;
import java.util.HashMap;
import java.util.Map;
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;
public class ExampleContentProvider extends ContentProvider {
/*
* Defines a handle to the database helper object. The MainDatabaseHelper class is defined
* in a following snippet.
*/
private MainDatabaseHelper mOpenHelper;
// Defines the database name
private static final String DBNAME = "mydb";
private static final int MAINS = 1 ;
private static final int MAIN_ID = 2 ;
/**
* A UriMatcher instance
*/
private static final UriMatcher sUriMatcher;
private static Map columnMap = new HashMap() ;
static{
// Create a new instance
sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
sUriMatcher.addURI(Main.AUTHORITY, "mains", MAINS) ;
sUriMatcher.addURI(Main.AUTHORITY, "main", MAIN_ID) ;
sUriMatcher.addURI(Main.AUTHORITY, "main/#", MAIN_ID) ;
columnMap.put("id","_ID") ;
columnMap.put("word","WORD") ;
}
public boolean onCreate() {
/*
* Creates a new helper object. This method always returns quickly.
* Notice that the database itself isn't created or opened
* until SQLiteOpenHelper.getWritableDatabase is called
*/
mOpenHelper = new MainDatabaseHelper(
getContext() // the application context
);
return true;
}
@Override
public int delete(Uri arg0, String arg1, String[] arg2) {
return 0;
}
@Override
public String getType(Uri uri) {
switch (sUriMatcher.match(uri)) {
case MAINS:{
return Main.CONTENT_TYPE;
}
case MAIN_ID:{
return Main.CONTENT_ITEM_TYPE;
}
}
return null;
}
@Override
public Uri insert(Uri uri, ContentValues values) {
if(sUriMatcher.match(uri) == MAIN_ID){
throw new IllegalArgumentException("Unknown URI " + uri);
}
ContentValues value ;
if(null != values){
value = new ContentValues(values) ;
}else{
value = new ContentValues() ;
}
SQLiteDatabase db = mOpenHelper.getWritableDatabase() ;
long rowId = db.insert(
"main",
null,
values) ;
// If the insert succeeded, the row ID exists.
if (rowId > 0) {
// Creates a URI with the note ID pattern and the new row ID appended to it.
Uri noteUri = ContentUris.withAppendedId(Uri.parse(Main.CONTENT_URI + "/main/"), rowId);
// Notifies observers registered against this provider that the data changed.
getContext().getContentResolver().notifyChange(noteUri, null);
return noteUri;
}
// If the insert didn't succeed, then the rowID is <= 0. Throws an exception.
throw new SQLException("Failed to insert row into " + uri);
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder sqb = new SQLiteQueryBuilder() ;
sqb.setTables("main") ;
switch (sUriMatcher.match(uri)) {
case MAINS :
sqb.setProjectionMap(columnMap) ;
break ;
case MAIN_ID :
sqb.setProjectionMap(columnMap) ;
sqb.appendWhere("_ID = " +
uri.getPathSegments().get(1)) ;
break ;
}
String orderBy;
// If no sort order is specified, uses the default
if (TextUtils.isEmpty(sortOrder)) {
orderBy = "_ID";
} else {
// otherwise, uses the incoming sort order
orderBy = sortOrder;
}
SQLiteDatabase db = mOpenHelper.getReadableDatabase();
Cursor c = sqb.query(
db,
projection,
selection,
selectionArgs,
null,
null,
orderBy) ;
c.setNotificationUri(getContext().getContentResolver(), uri);
return c;
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
return 0;
}
// A string that defines the SQL statement for creating a table
private static final String SQL_CREATE_MAIN = "CREATE TABLE " +
"main " + // Table's name
"(" + // The columns in the table
" _ID INTEGER PRIMARY KEY, " +
" WORD TEXT" +
" FREQUENCY INTEGER " +
" LOCALE TEXT )";
/**
* Helper class that actually creates and manages the provider's underlying data repository.
*/
protected static final class MainDatabaseHelper extends SQLiteOpenHelper {
/*
* Instantiates an open helper for the provider's SQLite data repository
* Do not do database creation and upgrade here.
*/
MainDatabaseHelper(Context context) {
super(context, DBNAME, null, 1);
}
/*
* Creates the data repository. This is called when the provider attempts to open the
* repository and SQLite reports that it doesn't exist.
*/
public void onCreate(SQLiteDatabase db) {
// Creates the main table
db.execSQL(SQL_CREATE_MAIN);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
}
2.定義權限
在manifest 中定義，permission
在節點里面，定義permission
3.provider添加權限
在 節點里面添加
android:writePermission和android:readPermission
android:writePermission="com.hualu.provider.WRITE"
android:readPermission="com.hualu.provider.READ">
在另一個應用訪問這個contentprovider
1.新建一個應用
2.在當前應用的manifest里面添加對之前定義的provider的權限的使用
3.在Activity里面通過ContentResolver調用provider
ContentValues values = new ContentValues() ;
values.put("WORD", "abcd") ;
Uri uri = this.getContentResolver().insert(
Uri.parse("content://com.hualu.contentprovider/mains"),
values) ;
String id = uri.getPathSegments().get(1) ;
Cursor cAll = this.getContentResolver().query(
Uri.parse("content://com.hualu.contentprovider/mains"),
null,
null,
null,
null);
Cursor c = this.getContentResolver().query(
Uri.parse("content://com.hualu.contentprovider/main/1"),
null,
null,
null,
null);
Toast.makeText(this, "insert success id = " + id + " ," +
" \r\n All = " + cAll.getCount() + " , " +
"\r\n one = " + c.getCount(),
Toast.LENGTH_SHORT).show() ;
代碼下載地址：
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