ANDROID_MARS学习笔记_S01原始版_010_ContentProvider

提示：扫一扫查出行
【扫一扫了解最新限行尾号】
复制提示

一、简介

一、代码
1.xml
(1)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="fill_parent"

     android:layout_height="fill_parent">

     <Button android:id="@+id/insertButton" android:layout_width="fill_parent"

         android:layout_height="wrap_content" android:text="insert" />

     <Button android:id="@+id/queryButton" android:layout_width="fill_parent"

         android:layout_height="wrap_content" android:text="query" />

 </LinearLayout>

(2)AndroidManifest.xml.xml

 <?xml version="1.0" encoding="utf-8"?>

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"

     package="com.example.s01_original_e16_textcp"

     android:versionCode="1"

     android:versionName="1.0" >

     <uses-sdk

         android:minSdkVersion="8"

         android:targetSdkVersion="21" />

     <application

         android:allowBackup="true"

         android:icon="@drawable/ic_launcher"

         android:label="@string/app_name"

         android:theme="@style/AppTheme" >

         <activity

             android:name=".CPActivity"

             android:label="@string/app_name" >

             <intent-filter>

                 <action android:name="android.intent.action.MAIN" />

                 <category android:name="android.intent.category.LAUNCHER" />

             </intent-filter>

         </activity>

         <provider android:name="com.example.s01_original_e16_textcp.FirstContentProvider"

             android:authorities="tony.cp.FirstContentProvider" />

     </application>

 </manifest>

2.java
(1)CPActivity.java

 package com.example.s01_original_e16_textcp;

 import android.app.Activity;

 import android.content.ContentValues;

 import android.database.Cursor;

 import android.net.Uri;

 import android.os.Bundle;

 import android.view.View;

 import android.widget.Button;

 import com.example.s01_original_e16_textcp.FirstProviderMetaData.UserTableMetaData;

 public class CPActivity extends Activity {

     /** Called when the activity is first created. */

     private Button insertButton = null;

     private Button queryButton = null;

     @Override

     public void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.main);

         insertButton = (Button) findViewById(R.id.insertButton);

         insertButton.setOnClickListener(new View.OnClickListener() {

             @Override

             public void onClick(View v) {

                 ContentValues values = new ContentValues();

                 values.put(FirstProviderMetaData.UserTableMetaData.USER_NAME,

                         "zhangsan");

                 Uri uri = getContentResolver().insert(

                         FirstProviderMetaData.UserTableMetaData.CONTENT_URI,

                         values);

                 System.out.println("uri  ---> " + uri.toString());

             }

         });

         queryButton = (Button) findViewById(R.id.queryButton);

         queryButton.setOnClickListener(new View.OnClickListener() {

             @Override

             public void onClick(View v) {

                 Cursor c = getContentResolver().query(

                         FirstProviderMetaData.UserTableMetaData.CONTENT_URI,

                         null, null, null, null);

                 while (c.moveToNext()) {

                     System.out.println(c.getString(c

                             .getColumnIndex(UserTableMetaData.USER_NAME)));

                 }

             }

         });

     }

 }

(2)FirstContentProvider.java

 package com.example.s01_original_e16_textcp;

 import java.util.HashMap;

 import android.content.ContentProvider;

 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.database.sqlite.SQLiteQueryBuilder;

 import android.net.Uri;

 import android.text.TextUtils;

 import com.example.s01_original_e16_textcp.FirstProviderMetaData.UserTableMetaData;

 public class FirstContentProvider extends ContentProvider {

     // UriMatcher用来检查URI是否合法

     public static final UriMatcher uriMatcher;

     public static final int INCOMING_USER_COLLECTION = 1;

     public static final int INCOMING_USER_SINGLE = 2;

     private DatabaseHelper dh;

     static {

         uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

         uriMatcher.addURI(FirstProviderMetaData.AUTHORITY, "users",

                 INCOMING_USER_COLLECTION);

         uriMatcher.addURI(FirstProviderMetaData.AUTHORITY, "users/#",

                 INCOMING_USER_SINGLE);

     }

     //相当于给sql的列起别名

     public static HashMap<String, String> userProjectionMap;

     static {

         userProjectionMap = new HashMap<String, String>();

         userProjectionMap.put(UserTableMetaData._ID, UserTableMetaData._ID);

         userProjectionMap.put(UserTableMetaData.USER_NAME,

                 UserTableMetaData.USER_NAME);

     }

     @Override

     public int delete(Uri arg0, String arg1, String[] arg2) {

         // TODO Auto-generated method stub

         System.out.println("delete...");

         return 0;

     }

     // 根据传入的URI，返回该URI所表示的数据类型

     @Override

     public String getType(Uri uri) {

         System.out.println("getType...");

         switch (uriMatcher.match(uri)) {

         case INCOMING_USER_COLLECTION:

             return UserTableMetaData.CONTENT_TYPE;

         case INCOMING_USER_SINGLE:

             return UserTableMetaData.CONTENT_TYPE_ITEM;

         default:

             throw new IllegalArgumentException("Unknow URI " + uri);

         }

     }

     /**

      * 该函数的返回值是一个Uri，这个Uri表示的是刚刚那使用这个函数所插入的数据

      * content://ycitss.cp.firstContentProivder/users/1

      */

     @Override

     public Uri insert(Uri uri, ContentValues values) {

         System.out.println("insert...");

         SQLiteDatabase db = dh.getWritableDatabase();

         long rowId = db.insert(UserTableMetaData.TABLE_NAME, null, values);

         if (rowId > 0) {

             Uri insertedUserUri = ContentUris.withAppendedId(

                     UserTableMetaData.CONTENT_URI, rowId);

             // 通知监听器，数据已经修改

             getContext().getContentResolver().notifyChange(insertedUserUri,

                     null);

             return insertedUserUri;

         }

         throw new SQLException("Failed to insert row into " + uri);

     }

     // 是一个回调方法，所以说在ContentProvider创建的时候执行

     @Override

     public boolean onCreate() {

         dh = new DatabaseHelper(getContext(),

                 FirstProviderMetaData.DATABASE_NAME);

         System.out.println("onCreate...");

         return true;

     }

     @Override

     public Cursor query(Uri uri, String[] projection, String selection,

             String[] selectionArgs, String sortOrder) {

         SQLiteQueryBuilder qb = new SQLiteQueryBuilder();

         switch (uriMatcher.match(uri)) {

         case INCOMING_USER_COLLECTION:

             qb.setTables(UserTableMetaData.TABLE_NAME);

             qb.setProjectionMap(userProjectionMap);

             break;

         case INCOMING_USER_SINGLE:

             qb.setTables(UserTableMetaData.TABLE_NAME);

             qb.setProjectionMap(userProjectionMap);

             qb.appendWhere(UserTableMetaData._ID + "="

                     + uri.getPathSegments().get(1));

             break;

         }

         String orderBy;

         if (TextUtils.isEmpty(sortOrder)) {

             orderBy = UserTableMetaData.DEFAULT_SORT_ORDER;

         } else {

             orderBy = sortOrder;

         }

         SQLiteDatabase db = dh.getWritableDatabase();

         Cursor c = qb.query(db, projection, selection, selectionArgs, null,

                 null, orderBy);

         c.setNotificationUri(getContext().getContentResolver(), uri);

         System.out.println("query...");

         return c;

     }

     @Override

     public int update(Uri uri, ContentValues values, String selection,

             String[] selectionArgs) {

         System.out.println("update...");

         return 0;

     }

 }

(3)FirstProviderMetaData.java

 package com.example.s01_original_e16_textcp;

 import android.net.Uri;

 import android.provider.BaseColumns;

 public class FirstProviderMetaData {

     // 必需与AndroidManifest.xml中定义的android:authorities一致

     public static final String AUTHORITY = "tony.cp.FirstContentProvider";

     // 数据库名称

     public static final String DATABASE_NAME = "FirstProvider.db";

     // 数据库版本

     public static final int DATABASE_VERSION = 1;

     // 表名

     public static final String USERS_TABLE_NAME = "users";

     public static final class UserTableMetaData implements BaseColumns {

         // 表名

         public static final String TABLE_NAME = "users";

         // 访问该ContentProvider的URI

         public static final Uri CONTENT_URI = Uri.parse("content://"

                 + AUTHORITY + "/users");

         // 该contentProvider所返回的数据类型的定义

         public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.firstprovider.user";//访问整张表

         public static final String CONTENT_TYPE_ITEM = "vnd.android.cursor.item/vnd.firstprovider.user";//取一条数据

         // 列名

         public static final String USER_NAME = "name";

         // 默认的排序方法

         public static final String DEFAULT_SORT_ORDER = "_id desc";

     }

 }

(4)DatabaseHelper.java

 package com.example.s01_original_e16_textcp;

 import android.content.Context;

 import android.database.sqlite.SQLiteDatabase;

 import android.database.sqlite.SQLiteDatabase.CursorFactory;

 import android.database.sqlite.SQLiteOpenHelper;

 public class DatabaseHelper extends SQLiteOpenHelper {

     private static final int VERSION = 1;

     public DatabaseHelper(Context context, String name, CursorFactory factory,

             int version) {

         super(context, name, factory, version);

         // TODO Auto-generated constructor stub

     }

     public DatabaseHelper(Context context, String name, int version) {

         this(context, name, null, version);

     }

     public DatabaseHelper(Context context, String name) {

         this(context, name, VERSION);

     }

     // 该函数是在第一次创建数据库的时候执行，实际上是在第一次得到SQLiteDAtabase对象的时候，才会调用这个方法

     @Override

     public void onCreate(SQLiteDatabase db) {

         System.out.println("cteate a Database");

         // execSQL函数用于执行SQL语句

         db.execSQL("create table " + FirstProviderMetaData.USERS_TABLE_NAME

                 + "(" + FirstProviderMetaData.UserTableMetaData._ID

                 + " INTEGER_PARIMARY_AUTOINCREMENT,"

                 + FirstProviderMetaData.UserTableMetaData.USER_NAME

                 + " varchar(20))");

     }

     @Override

     public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {

         System.out.println("update a Database");

     }

 }