Chinaunix首页 | 论坛 | 博客

gdliweibing的ChinaUnix博客

首页　| 　博文目录　| 　关于我

gdliweibing

  • 博客访问： 208413
  • 博文数量： 102
  • 博客积分： 0
  • 博客等级： 民兵
  • 技术积分： 1015
  • 用 户 组： 普通用户
  • 注册时间： 2013-06-05 16:45
文章分类

全部博文（102）

文章存档

2014年（73）

2013年（29）

我的朋友
最近访客
推荐博文
相关博文
01_19_ContentProvider初步

分类： Android平台

2014-04-10 07:28:38

01_19_ContentProvider初步（插入数据成功、但查询失败，得进一步调试）


最重要的是在AndroidMainfest.xml中注册provider

点击(此处)折叠或打开

  1. <provider android:name="mars.cp.FirstContentProvider"
  2.                  android:authorities="mars.cp.FirstContentProvider"/>
具体如下：

点击(此处)折叠或打开

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <manifest xmlns:android=""
  3.       package="mars.cp"
  4.       android:versionCode="1"
  5.       android:versionName="1.0">
  6.     <application android:icon="@drawable/icon" android:label="@string/app_name">
  7.         <activity android:name=".CPActivity"
  8.                   android:label="@string/app_name">
  9.             <intent-filter>
  10.                 <action android:name="android.intent.action.MAIN" />
  11.                 <category android:name="android.intent.category.LAUNCHER" />
  12.             </intent-filter>
  13.         </activity>
  14.         <provider android:name="mars.cp.FirstContentProvider"
  15.                  android:authorities="mars.cp.FirstContentProvider"/>
  16.     </application>
  17.     <uses-sdk android:minSdkVersion="4" />
  18. </manifest>

点击(此处)折叠或打开

  1. //CPActivity.java
  2. package mars.cp;

  4. import mars.cp.FirstProviderMetaData.UserTableMetaData;
  5. import android.app.Activity;
  6. import android.content.ContentValues;
  7. import android.database.Cursor;
  8. import android.net.Uri;
  9. import android.os.Bundle;
  10. import android.view.View;
  11. import android.view.View.OnClickListener;
  12. import android.widget.Button;

  14. public class CPActivity extends Activity {
  15.     /** Called when the activity is first created. */
  16.     private Button insertButton = null;
  17.     private Button queryButton = null;

  19.     @Override
  20.     public void onCreate(Bundle savedInstanceState) {
  21.         super.onCreate(savedInstanceState);
  22.         setContentView(R.layout.main);
  23.         queryButton = (Button) findViewById(R.id.query);
  24.         queryButton.setOnClickListener(new QueryListener());
  25.         insertButton = (Button) findViewById(R.id.insert);
  26.         insertButton.setOnClickListener(new InsertListener());
  27.     //    System.out.println(getContentResolver().getType(FirstProviderMetaData.UserTableMetaData.CONTENT_URI));
  28.     }

  30.     class InsertListener implements OnClickListener {

  32.         @Override
  33.         public void onClick(View v) {
  34.             // TODO Auto-generated method stub
  35.             ContentValues values = new ContentValues(); //USER_NAME = "name"
  36.             values.put(FirstProviderMetaData.UserTableMetaData.USER_NAME,
  37.                     "zhangsan");
  38.             Uri uri = getContentResolver()
  39.                     .insert(            //CONTENT_URI = Uri.parse("content://" + AUTHORIY + "/users");
  40.                             FirstProviderMetaData.UserTableMetaData.CONTENT_URI,
  41.                             values);
  42.             System.out.println("uri--->" + uri.toString());
  43.         }

  45.     }

  47.     class QueryListener implements OnClickListener {

  49.         @Override
  50.         public void onClick(View v) {
  51.             // TODO Auto-generated method stub
  52.             Cursor c = getContentResolver().query( //这里有问题
  53.                     FirstProviderMetaData.UserTableMetaData.CONTENT_URI, null,
  54.                     null, null, null);
  55.             //query(Uri uri, String[] projection, String selection, String[] selectionArgs,String sortOrder)
  56.             while(c.moveToNext()){
  57.                 System.out.println(c.getString(c.getColumnIndex(UserTableMetaData.USER_NAME)));
  58.             }
  59.         }

  61.     }
  62. }

点击(此处)折叠或打开

  1. //FirstContentProvider.java
  2. package mars.cp;

  4. import java.util.HashMap;

  6. import mars.cp.FirstProviderMetaData.UserTableMetaData;
  7. import mars.sqlite3.db.DatabaseHelper;
  8. import android.content.ContentProvider;
  9. import android.content.ContentUris;
  10. import android.content.ContentValues;
  11. import android.content.UriMatcher;
  12. import android.database.Cursor;
  13. import android.database.SQLException;
  14. import android.database.sqlite.SQLiteDatabase;
  15. import android.database.sqlite.SQLiteQueryBuilder;
  16. import android.net.Uri;
  17. import android.text.TextUtils;

  19. public class FirstContentProvider extends ContentProvider {

  21.     public static final UriMatcher uriMatcher;
  22.     public static final int INCOMING_USER_COLLECTION = 1;
  23.     public static final int INCOMING_USER_SINGLE = 2;
  24.     private DatabaseHelper dh;
  25.     static {
  26.         uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
  27.         uriMatcher.addURI(FirstProviderMetaData.AUTHORIY, "/users",
  28.                 INCOMING_USER_COLLECTION);
  29.         uriMatcher.addURI(FirstProviderMetaData.AUTHORIY, "/users/#",
  30.                 INCOMING_USER_SINGLE);
  31.     }
  32.     
  33.     public static HashMap<String,String> userProjectionMap;
  34.     static
  35.     {
  36.         userProjectionMap = new HashMap<String,String>();
  37.         userProjectionMap.put(UserTableMetaData._ID,UserTableMetaData._ID);
  38.         userProjectionMap.put(UserTableMetaData.USER_NAME, UserTableMetaData.USER_NAME);
  39.     }
  40.     @Override
  41.     public int delete(Uri arg0, String arg1, String[] arg2) {
  42.         // TODO Auto-generated method stub
  43.         System.out.println("delete");
  44.         return 0;
  45.     }

  47.     //根据传入的URI，返回该URI所表示的数据类型
  48.     @Override
  49.     public String getType(Uri uri) {
  50.         // TODO Auto-generated method stub
  51.         System.out.println("getType");
  52.         switch(uriMatcher.match(uri)){
  53.         case INCOMING_USER_COLLECTION:
  54.             return UserTableMetaData.CONTENT_TYPE;
  55.         case INCOMING_USER_SINGLE:
  56.             return UserTableMetaData.CONTENT_TYPE_ITEM;
  57.         default:
  58.             throw new IllegalArgumentException("Unknown URI" + uri);
  59.         }
  60.     }

  62.     /**
  63.      * 该函数的返回值是一个Uri，这个Uri表示的是刚刚使用这个函数所插入的数据
  64.      * content://mars.cp.FirstContentProvider/users/1
  65.      */
  66.     @Override
  67.     public Uri insert(Uri uri, ContentValues values) {
  68.         System.out.println("insert");
  69.         SQLiteDatabase db = dh.getWritableDatabase();
  70.         long rowId = db.insert(UserTableMetaData.TABLE_NAME, null, values);//TABLE_NAME = "users";
  71.         if(rowId > 0){
  72.             Uri insertedUserUri = ContentUris.withAppendedId(UserTableMetaData.CONTENT_URI, rowId);
  73.             //通知监听器，数据已经改变
  74.             getContext().getContentResolver().notifyChange(insertedUserUri, null);
  75.             return insertedUserUri;
  76.         }
  77.         throw new SQLException("Failed to insert row into" + uri);
  78.     }

  80.     //是一个回调方法，所以说在ContentProvider创建的时候执行
  81.     @Override
  82.     public boolean onCreate() {
  83.         //打开数据库
  84.         dh = new DatabaseHelper(getContext(),FirstProviderMetaData.DATABASE_NAME);//DATABASE_NAME = "FirstProvider.db";
  85.         System.out.println("onCreate");
  86.         return true;
  87.     }

  89.     @Override
  90.     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
  91.             String sortOrder) {
  92.         SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
  93.         switch(uriMatcher.match(uri)){
  94.         case INCOMING_USER_COLLECTION:
  95.             qb.setTables(UserTableMetaData.TABLE_NAME);
  96.             qb.setProjectionMap(userProjectionMap);
  97.             break;
  98.         case INCOMING_USER_SINGLE:
  99.             qb.setTables(UserTableMetaData.TABLE_NAME); //TABLE_NAME = "users"
  100.             qb.setProjectionMap(userProjectionMap);
  101.             qb.appendWhere(UserTableMetaData._ID + "=" + uri.getPathSegments().get(1));
  102.             break;
  103.         }
  104.         String orderBy;
  105.         if(TextUtils.isEmpty(sortOrder)){
  106.             orderBy = UserTableMetaData.DEFAULT_SORT_ORDER; //String DEFAULT_SORT_ORDER = "_id desc";
  107.         }
  108.         else{
  109.             orderBy = sortOrder;
  110.         }
  111.         SQLiteDatabase db = dh.getWritableDatabase();
  112.         //Cursor c = qb.query(db, projectionIn, selection, selectionArgs, groupBy, having, sortOrder)
  113.         Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, orderBy);//这里有问题
  114.     
  115.         c.setNotificationUri(getContext().getContentResolver(), uri);
  116.         System.out.println("query");
  117.         return c;
  118.     }
  119.     //12-25 04:08:43.103: E/AndroidRuntime(487):     at mars.cp.FirstContentProvider.query(FirstContentProvider.java:111)
  120.     //12-25 04:08:43.103: E/AndroidRuntime(487): java.lang.IllegalStateException: Invalid tables
  121.     //12-25 04:08:43.103: E/AndroidRuntime(487):     at mars.cp.CPActivity$QueryListener.onClick(CPActivity.java:51)

  123.     @Override
  124.     public int update(Uri arg0, ContentValues arg1, String arg2, String[] arg3) {
  125.         // TODO Auto-generated method stub
  126.         System.out.println("update");
  127.         return 0;
  128.     }

  130. }


点击(此处)折叠或打开

  1. //FirstProviderMetaData.java
  2. package mars.cp;

  4. import android.net.Uri;
  5. import android.provider.BaseColumns;

  7. public class FirstProviderMetaData {
  8.     public static final String AUTHORIY = "mars.cp.FirstContentProvider";
  9.     //数据库名称
  10.     public static final String DATABASE_NAME = "FirstProvider.db";
  11.     //数据库的版本
  12.     public static final int DATABASE_VERSION = 1;
  13.     //表名
  14.     public static final String USERS_TABLE_NAME = "users";
  15.     
  16.     public static final class UserTableMetaData implements BaseColumns{
  17.         //表名
  18.         public static final String TABLE_NAME = "users";
  19.         //访问该ContentProvider的URI
  20.         public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORIY + "/users");
  21.         //该ContentProvider所返回的数据类型的定义
  22.         public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.firstprovider.user";
  23.         public static final String CONTENT_TYPE_ITEM = "vnd.android.cursor.item/vnd.firstprovider.user";
  24.         //列名
  25.         public static final String USER_NAME = "name";
  26.         //默认的排序方法
  27.         public static final String DEFAULT_SORT_ORDER = "_id desc";
  28.     }
  29. }


点击(此处)折叠或打开

  1. //DatabaseHelper.java
  2. package mars.sqlite3.db;

  4. import mars.cp.FirstProviderMetaData;
  5. import android.content.Context;
  6. import android.database.sqlite.SQLiteDatabase;
  7. import android.database.sqlite.SQLiteOpenHelper;
  8. import android.database.sqlite.SQLiteDatabase.CursorFactory;

  10. //DatabaseHelper作为一个访问SQLite的助手类，提供两个方面的功能，
  11. //第一，getReadableDatabase(),getWritableDatabase()可以获得SQLiteDatabse对象，通过该对象可以对数据库进行操作
  12. //第二，提供了onCreate()和onUpgrade()两个回调函数，允许我们在创建和升级数据库时，进行自己的操作

  14. public class DatabaseHelper extends SQLiteOpenHelper {

  16.     private static final int VERSION = 1;

  18.     // 在SQLiteOepnHelper的子类当中，必须有该构造函数
  19.     public DatabaseHelper(Context context, String name, CursorFactory factory,
  20.             int version) {
  21.         // 必须通过super调用父类当中的构造函数
  22.         super(context, name, factory, version);
  23.         // TODO Auto-generated constructor stub
  24.     }

  26.     public DatabaseHelper(Context context, String name) {
  27.         this(context, name, VERSION);
  28.     }

  30.     public DatabaseHelper(Context context, String name, int version) {
  31.         this(context, name, null, version);
  32.     }

  34.     // 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SQLiteDatabse对象的时候，才会调用这个方法
  35.     @Override
  36.     public void onCreate(SQLiteDatabase db) {
  37.         // TODO Auto-generated method stub
  38.         System.out.println("create a Database");
  39.         // execSQL函数用于执行SQL语句
  40.         db.execSQL("create table " + FirstProviderMetaData.USERS_TABLE_NAME
  41.                 + "(" + FirstProviderMetaData.UserTableMetaData._ID
  42.                 + " INTEGER PRIMARY KEY AUTOINCREMENT,"
  43.                 + FirstProviderMetaData.UserTableMetaData.USER_NAME
  44.                 + " varchar(20));");
  45.     }

  47.     @Override
  48.     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
  49.         // TODO Auto-generated method stub
  50.         System.out.println("update a Database");
  51.     }

  53. }



阅读(434) | 评论(0) | 转发(0) |
0

上一篇：09_HTTP操作（三） (HTTP请求方法：1、GET方法发送请求，2POS方法发送请求)

下一篇：01_25_Service初步（一）

给主人留下些什么吧！~~
关于我们 | 关于IT168 | 联系方式 | 广告合作 | 法律声明 | 免费注册

Copyright 2001-2010 ChinaUnix.net All Rights Reserved 北京皓辰网域网络信息技术有限公司. 版权所有

感谢所有关心和支持过ChinaUnix的朋友们

16024965号-6