Android ContentProvider和ContentResolver实例
2024-05-15 02:14:34
ContentResolver和ContentProvider通过相同的URI联系，实现数据共享。我重写了public class MyAdapter extends BaseAdapter，putData()，然后listview.setAdapter(myAdapter)显示数据。edit layout用来安排显示数据的格式。主要代码来自《安卓编程兵书》p311。完整的URI如下，"content://"+AUTHORITY+"/books"，books是图书信息表的名字，AUTHORITY定义如下：
public static final String AUTHORITY="lmy.com.bookinfo_provider"1.CotentProvider
//《安卓变成兵书》p311
//sample_8_6.java
package lmy.com.sample_8_6;import android.content.ContentProvider;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.text.TextUtils;public class Sample_8_6 extends ContentProvider{private DB_helper dbhelper = null;private static UriMatcher sUriMatcher =null;private static final int BOOKS_RECORDS = 1;private static final int BOOKS_RECORD =2;static{sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);sUriMatcher.addURI(Bookinfo_provider.AUTHORITY,"books",BOOKS_RECORDS);sUriMatcher.addURI(Bookinfo_provider.AUTHORITY,"books/#",BOOKS_RECORD);}@Overridepublic boolean onCreate(){dbhelper = new DB_helper(this.getContext());return true;}public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.androidbook.book";public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/vnd.androidbook.book";@Overridepublic String getType(Uri uri){//TODO Auto-generated method stubswitch(sUriMatcher.match(uri)) {case BOOKS_RECORDS:return Bookinfo_provider.Bookinfo.CONTENT_TYPE;case BOOKS_RECORD:return Bookinfo_provider.Bookinfo.CONTENT_ITEM_TYPE;default:throw new IllegalArgumentException("Uknown URI "+uri);}}@Overridepublic Uri insert(Uri uri,ContentValues values){if(sUriMatcher.match(uri)!=BOOKS_RECORDS){throw new IllegalArgumentException("Unknown URI "+uri);}if(!values.containsKey(Bookinfo_provider.Bookinfo.BOOK_NAME)){throw new SQLException("Failed to insert,please input Book name"+uri);}if(!values.containsKey(Bookinfo_provider.Bookinfo.BOOK_ISBN)){values.put(Bookinfo_provider.Bookinfo.BOOK_ISBN,"Unknown ISBN");}if(!values.containsKey(Bookinfo_provider.Bookinfo.BOOK_AUTHOR)){values.put(Bookinfo_provider.Bookinfo.BOOK_AUTHOR,"Unknown author");}SQLiteDatabase db = dbhelper.getWritableDatabase();long rowID = db.insert(Bookinfo_provider.Bookinfo.TABLE_NAME,Bookinfo_provider.Bookinfo.BOOK_NAME,values);if(rowID>0){Uri insertBookedUri = ContentUris.withAppendedId(Bookinfo_provider.Bookinfo.CONTENT_URI,rowID);getContext().getContentResolver().notifyChange(insertBookedUri,null);return insertBookedUri;}throw new SQLException("Failed to insert row int "+uri);}@Overridepublic int delete(Uri uri,String selection,String[] selectionArgs){SQLiteDatabase db = dbhelper.getWritableDatabase();int count = 0;switch(sUriMatcher.match(uri)){case BOOKS_RECORDS:count = db.delete(Bookinfo_provider.Bookinfo.TABLE_NAME,selection,selectionArgs);break;case BOOKS_RECORD:String rowID = uri.getPathSegments().get(1);String where = Bookinfo_provider.Bookinfo._ID+"="+rowID+(!TextUtils.isEmpty(selection)?" AND ("+selectionArgs+')':"");count = db.delete(Bookinfo_provider.Bookinfo.TABLE_NAME,where,selectionArgs);break;default:throw new IllegalArgumentException("Unknown URI"+uri);}db.close();this.getContext().getContentResolver().notifyChange(uri,null);return count;}@Overridepublic int update(Uri uri,ContentValues values,String selection,String[] selectionArgs){SQLiteDatabase db = dbhelper.getWritableDatabase();int count = 0;switch (sUriMatcher.match(uri)){case BOOKS_RECORDS:count = db.update(Bookinfo_provider.BOOKS_TABLE_NAME,values,selection,selectionArgs);break;case BOOKS_RECORD:String rowID = uri.getPathSegments().get(1);String where = Bookinfo_provider.Bookinfo._ID+"="+rowID+(!TextUtils.isEmpty(selection)?" AND("+selection+')':"");count = db.update(Bookinfo_provider.BOOKS_TABLE_NAME,values,where,selectionArgs);break;default:throw new IllegalArgumentException("Uknown URI "+uri);}getContext().getContentResolver().notifyChange(uri,null);return count;}@Overridepublic Cursor query(Uri uri,String[] projection,String selection,String[] selectionArgs,String sortOrder){Cursor cursor = null;SQLiteDatabase db = dbhelper.getReadableDatabase();switch(sUriMatcher.match(uri)){case BOOKS_RECORDS:cursor = db.query(Bookinfo_provider.BOOKS_TABLE_NAME,projection,selection,selectionArgs,null,null,sortOrder);break;case BOOKS_RECORD:String id = uri.getPathSegments().get(1);cursor = db.query(Bookinfo_provider.BOOKS_TABLE_NAME,projection,Bookinfo_provider.Bookinfo._ID+"="+id+(!TextUtils.isEmpty(selection)?" AND ("+selectionArgs+')':""),selectionArgs,null,null,sortOrder);break;default:throw new IllegalArgumentException("Unknown URI "+uri);}ContentResolver cr = this.getContext().getContentResolver();cursor.setNotificationUri(cr,uri);return cursor;}
}//MainActivity.java
package lmy.com.sample_8_6;import android.app.ListActivity;
import android.os.Bundle;public class MainActivity extends ListActivity {private Sample_8_6 mContentProvider=new Sample_8_6();@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}}
//DB_helper.java
package lmy.com.sample_8_6;import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
//创建数据库
public class DB_helper extends SQLiteOpenHelper {public DB_helper(Context context){super(context,Bookinfo_provider.DATABASE_NAME,null,Bookinfo_provider.DATABASE_VERSION);}
//创建图书信息表@Overridepublic void onCreate(SQLiteDatabase db){String sql = "CREATE TABLE "+ Bookinfo_provider.Bookinfo.TABLE_NAME+" ("+ Bookinfo_provider.Bookinfo._ID+" INTEGER PRIMARY KEY AUTOINCREMENT,"+ Bookinfo_provider.Bookinfo.BOOK_NAME+" TEXT,"+ Bookinfo_provider.Bookinfo.BOOK_ISBN+" TEXT,"+ Bookinfo_provider.Bookinfo.BOOK_AUTHOR+" TEXT)";db.execSQL(sql);}@Overridepublic void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion){String sql = "DROP TABLE IF EXISTS "+Bookinfo_provider.Bookinfo.TABLE_NAME;db.execSQL(sql);onCreate(db);}
}
//Bookinfo_provider.java
package lmy.com.sample_8_6;import android.net.Uri;
import android.provider.BaseColumns;public class Bookinfo_provider {public static final String DATABASE_NAME = "book.db";public static final int DATABASE_VERSION = 1;public static final String AUTHORITY="lmy.com.bookinfo_provider";public static final String BOOKS_TABLE_NAME = "books";public static final class Bookinfo implements BaseColumns {public static final String TABLE_NAME = "books";public static final String BOOK_NAME = "name";public static final String BOOK_ISBN = "isbn";public static final String BOOK_AUTHOR = "author";public static final String _ID = "_id";public static final Uri CONTENT_URI = Uri.parse("content://"+AUTHORITY+"/books");public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.androidbook.book";public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/vnd.androidbook.book";public static final String DEFAULT_SORT_ORD="id DESC";}
}<!--main.xml-->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"
><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="BookinfoProvider!"/><ListViewandroid:id="@android:id/list"android:layout_width="match_parent"android:layout_height="366dp" /></LinearLayout><!--edit.xml-->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:id="@+id/edit"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"><LinearLayoutandroid:orientation="horizontal"android:layout_width="match_parent"android:layout_height="wrap_content"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="书名" /><EditTextandroid:id="@+id/name"android:layout_width="325dp"android:layout_height="wrap_content"android:inputType="text" /></LinearLayout><LinearLayoutandroid:orientation="horizontal"android:layout_width="match_parent"android:layout_height="wrap_content"><TextViewandroid:text="书号"android:layout_width="wrap_content"android:layout_height="wrap_content"/><EditTextandroid:id="@+id/isbn"android:layout_width="323dp"android:layout_height="wrap_content"android:inputType="text" /></LinearLayout><LinearLayoutandroid:orientation="horizontal"android:layout_width="match_parent"android:layout_height="wrap_content"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="作者" /><EditTextandroid:id="@+id/author"android:layout_width="322dp"android:layout_height="wrap_content"android:inputType="text" /></LinearLayout><LinearLayoutandroid:orientation="horizontal"android:layout_width="match_parent"android:layout_height="wrap_content"><Buttonandroid:text="取消"android:layout_width="wrap_content"android:layout_height="wrap_content"android:id="@+id/cancel"/><Buttonandroid:id="@+id/ok"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_toEndOf="@+id/cancel"android:text="确定" /></LinearLayout>
</LinearLayout>
<!--AndroidManifest.xml-->
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="lmy.com.sample_8_6"><applicationandroid:allowBackup="true"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:roundIcon="@mipmap/ic_launcher_round"android:supportsRtl="true"android:theme="@style/AppTheme"><providerandroid:authorities="lmy.com.bookinfo_provider"android:name=".Sample_8_6"android:exported="true" /><activity android:name=".MainActivity"><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity></application></manifest>2.ContentResolver
//《安卓编程兵书》p311
//Sample_8_6.java
package lmy.com.sample_8_6_test;import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;public class Sample_8_6_test extends AppCompatActivity {private ListView listview;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);listview = (ListView)findViewById(R.id.myListView);MyAdapter myAdapter = new MyAdapter(this,putData());listview.setAdapter(myAdapter);try{test_insert();test_insert();test_insert();test_delete();test_update();test_find();}catch (Throwable e){System.out.println(e.toString());e.printStackTrace();}}public void test_insert() throws Throwable{ContentResolver cr = this.getContentResolver();//Uri inserturi = Uri.parse("content://lmy.com.bookinfo_provider/books");Uri inserturi = Uri.parse("content://"+Bookinfo_provider.AUTHORITY+"/books");ContentValues cv = new ContentValues();cv.put("name","Android");cv.put("isbn","123456");Uri re_uri = cr.insert(inserturi,cv);System.out.println("test_insert:"+re_uri);}public void test_delete() throws Throwable{ContentResolver contentResolver = getContentResolver();//Uri uri = Uri.parse("content://lmy.com.bookinfo_provider/books/1");Uri uri = Uri.parse("content://"+Bookinfo_provider.AUTHORITY+"/books/1");//"/books/1"表示books表中的第一条记录contentResolver.delete(uri,null,null);}public void test_update() throws Throwable{ContentResolver contentResolver = getContentResolver();//Uri updateUri = Uri.parse("content://lmy.com.bookinfo_provider/books/2");Uri updateUri = Uri.parse("content://"+Bookinfo_provider.AUTHORITY+"/books/2");ContentValues values = new ContentValues();values.put("name","Android示例");contentResolver.update(updateUri,values,null,null);System.out.println("修改完成");}public void test_find() throws Throwable{ContentResolver contentResolver = getContentResolver();//Uri uri = Uri.parse("content://lmy.com.bookinfo_provider/books");Uri uri = Uri.parse("content://"+Bookinfo_provider.AUTHORITY+"/books");Cursor cursor =contentResolver.query(uri,null,null,null,null);while(((Cursor) cursor).moveToNext()){String id = cursor.getString(0);String name = cursor.getString(1);String isbn = cursor.getString(2);String author = cursor.getString(3);System.out.println("_id="+id+",name="+name+",isbn="+isbn+",author="+author);}cursor.close();}public List<Map<String,Object>> putData(){List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();Map<String,Object> map1 ;ContentResolver contentResolver = getContentResolver();//Uri uri = Uri.parse("content://lmy.com.bookinfo_provider/books");Uri uri = Uri.parse("content://"+Bookinfo_provider.AUTHORITY+"/books");Cursor cursor =contentResolver.query(uri,null,null,null,null);while(((Cursor) cursor).moveToNext()){String id = cursor.getString(0);String name = cursor.getString(1);String isbn = cursor.getString(2);String author = cursor.getString(3);System.out.println("_id="+id+",name="+name+",isbn="+isbn+",author="+author);map1 = new HashMap<String,Object>();map1.put("_id",id);map1.put("name",name);map1.put("isbn",isbn);map1.put("author",author);list.add(map1);}return list;}
}
//MyAdapter.java
package lmy.com.sample_8_6_test;import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.EditText;
import java.util.List;
import java.util.Map;public class MyAdapter extends BaseAdapter {private LayoutInflater mInflater;private List<Map<String,Object>> list;public MyAdapter(Context context , List<Map<String,Object>> list){this.mInflater = LayoutInflater.from(context);this.list = list;}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn list.size();}@Overridepublic Object getItem(int position) {// TODO Auto-generated method stubreturn list.get(position);}@Overridepublic long getItemId(int position) {// TODO Auto-generated method stubreturn position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {// TODO Auto-generated method stubViewHolder holder = null;if (convertView == null) {holder = new ViewHolder();convertView = mInflater.inflate(R.layout.edit, null);holder._id = (EditText) convertView.findViewById(R.id._id);holder.name = (EditText)convertView.findViewById(R.id.name);holder.isbn=(EditText)convertView.findViewById(R.id.isbn);holder.author=(EditText)convertView.findViewById(R.id.author);convertView.setTag(holder);}else{holder = (ViewHolder)convertView.getTag();}holder._id.setText((String)list.get(position).get("_id"));holder.name.setText((String)list.get(position).get("name"));holder.isbn.setText((String)list.get(position).get("isbn"));holder.author.setText((String)list.get(position).get("author"));return convertView;}public final class ViewHolder{public EditText _id;public EditText name;public EditText isbn;public EditText author;}}//Bookinfo_provider.java
package lmy.com.sample_8_6_test;import android.net.Uri;
import android.provider.BaseColumns;public class Bookinfo_provider {public static final String DATABASE_NAME = "book.db";public static final int DATABASE_VERSION = 1;public static final String AUTHORITY="lmy.com.bookinfo_provider";public static final String BOOKS_TABLE_NAME = "books";public static final class Bookinfo implements BaseColumns {public static final String TABLE_NAME = "books";public static final String BOOK_NAME = "name";public static final String BOOK_ISBN = "isbn";public static final String BOOK_AUTHOR = "author";public static final String _ID = "_id";public static final Uri CONTENT_URI = Uri.parse("content://"+AUTHORITY+"/books");public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.androidbook.book";public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/vnd.androidbook.book";public static final String DEFAULT_SORT_ORD="_id DESC";}
}<!--main.xml-->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"
><LinearLayoutandroid:layout_width="wrap_content"android:layout_height="wrap_content"><TextViewandroid:layout_width="50dp"android:layout_height="wrap_content"android:text="序号"/><TextViewandroid:layout_width="100dp"android:layout_height="wrap_content"android:text="书名" /><TextViewandroid:layout_width="100dp"android:layout_height="wrap_content"android:text="ISBN" /><TextViewandroid:layout_width="100dp"android:layout_height="wrap_content"android:text="作者" /></LinearLayout><ListViewandroid:id="@+id/myListView"android:layout_width="match_parent"android:layout_height="match_parent" /></LinearLayout><!--edit.xml-->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/edit"android:orientation="horizontal"android:layout_width="match_parent"android:layout_height="match_parent"><EditTextandroid:id="@+id/_id"android:layout_width="50dp"android:layout_height="wrap_content"android:inputType="number" /><EditTextandroid:id="@+id/name"android:layout_width="100dp"android:layout_height="wrap_content"android:inputType="text" /><EditTextandroid:id="@+id/isbn"android:layout_width="100dp"android:layout_height="wrap_content"android:inputType="text" /><EditTextandroid:id="@+id/author"android:layout_width="100dp"android:layout_height="wrap_content"android:inputType="text" /></LinearLayout>
<!--AndroidManifest.xml-->
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="lmy.com.sample_8_6_test"><applicationandroid:allowBackup="true"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:roundIcon="@mipmap/ic_launcher_round"android:supportsRtl="true"android:theme="@style/AppTheme"><activity android:name=".Sample_8_6_test"><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity></application></manifest>Android ContentProvider和ContentResolver实例相关推荐
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