android 数据共享 ContentProvider

1、定义我共享的SQLite的数据信息

package com.example.phonedemo.contentprovider;

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

public class MyDatabaseInfo {
    
    public static final String Auth = "com.example.phonedemo.contentprovider";
    public static final String DBNAME = "cp";
    public static final int DBVERSION = 1;
    
    public static class MyTabInfo implements BaseColumns{
        public static final String TABNAME = "member";

        public static final Uri CONTENT_URI = Uri.parse("content://" + Auth + "/" + TABNAME);
        public static final String CONTENT_LIST = "vnd.android.cursor.dir/vnd.phonedemocontentprovider.member";
        public static final String CONTENT_ITEM = "vnd.android.cursor.item/vnd.phonedemocontentprovider.member";
        
        public static final String NAME = "name";
        public static final String AGE = "age";
        public static final String EMAIL = "email";
    }

}

2、写一个类继承SQLiteOpenHelper，完成一些数据库的初始化的操作。

package com.example.phonedemo.contentprovider;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class MySQLiteOpenHepler extends SQLiteOpenHelper {

    public MySQLiteOpenHepler(Context context) {
        super(context, MyDatabaseInfo.DBNAME, null, MyDatabaseInfo.DBVERSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String sql = "CREATE TABLE " + MyDatabaseInfo.MyTabInfo.TABNAME + " ("
                + MyDatabaseInfo.MyTabInfo._ID + " INTEGER         PRIMARY KEY,"
                + MyDatabaseInfo.MyTabInfo.NAME + " VARCHAR(50)     NOT NULL,"
                + MyDatabaseInfo.MyTabInfo.AGE + " INTEGER             NOT NULL,"
                + MyDatabaseInfo.MyTabInfo.EMAIL + " VARCHAR(50)     NOT NULL"
                + ")";
        db.execSQL(sql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        String sql = "DROP TABLE IF EXISTS " + MyDatabaseInfo.MyTabInfo.TABNAME;
        db.execSQL(sql);
        this.onCreate(db);
    }

}

3、首先写一个类继承 ContentProvider

package com.example.phonedemo.contentprovider;

import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;

public class MyContentProvider extends ContentProvider {
    private static UriMatcher uriMatcher = null;
    private MySQLiteOpenHepler helper = null;
    private static final int GET_MEMBER_LIST = 1;
    private static final int GET_MEMBER_ITEM = 2;

    static {
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        uriMatcher.addURI(MyDatabaseInfo.Auth,
                MyDatabaseInfo.MyTabInfo.TABNAME, GET_MEMBER_LIST);
        uriMatcher.addURI(MyDatabaseInfo.Auth, MyDatabaseInfo.MyTabInfo.TABNAME
                + "/#", GET_MEMBER_ITEM);
    }

    @Override
    public int delete(Uri uri, String where, String[] whereArgs) {
        SQLiteDatabase db = this.helper.getWritableDatabase();
        int count = 0;
        switch (uriMatcher.match(uri)) {
        case GET_MEMBER_LIST:
            count = db.delete(MyDatabaseInfo.MyTabInfo.TABNAME, null, null);
            break;
        case GET_MEMBER_ITEM:
            count = db.delete(MyDatabaseInfo.MyTabInfo.TABNAME, where,
                    whereArgs);
            break;
        default:
            db.close();
            throw new UnsupportedOperationException("Not Support " + uri);
        }
        db.close();
        return count;
    }

    @Override
    public String getType(Uri arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        SQLiteDatabase db = this.helper.getWritableDatabase();
        long id = 0;
        switch (uriMatcher.match(uri)) {
        case GET_MEMBER_LIST:
            id = db.insert(MyDatabaseInfo.MyTabInfo.TABNAME, null, values);
            return ContentUris.withAppendedId(uri, id);
        case GET_MEMBER_ITEM:
            break;
        default:
            throw new UnsupportedOperationException("Not Support Uri: " + uri);
        }
        db.close();
        return null;
    }

    @Override
    public boolean onCreate() {
        // TODO Auto-generated method stub
        this.helper = new MySQLiteOpenHepler(super.getContext());
        return false;
    }

    @Override
    public Cursor query(Uri uri, String[] arg1, String arg2, String[] arg3,
            String arg4) {
        SQLiteDatabase db = this.helper.getWritableDatabase();
        Cursor cursor = null;
        switch (uriMatcher.match(uri)) {
        case GET_MEMBER_LIST:
            System.out.println("** get member list");
            cursor = db.query(MyDatabaseInfo.MyTabInfo.TABNAME, null, null, null, null, null, null);
            System.out.println("contentProvider cursor.getCount(): " + cursor.getCount());
            break;
        case GET_MEMBER_ITEM:
            System.out.println("** get member item");
            break;
        default:
            throw new UnsupportedOperationException("Not Support Uri: " + uri);
        }
        //db.close();
        return cursor;
    }

    @Override
    public int update(Uri uri, ContentValues values, String whereSelection,
            String[] whereArgs) {
        SQLiteDatabase db = this.helper.getWritableDatabase();
        int result = 0;
        switch (uriMatcher.match(uri)) {
        case GET_MEMBER_LIST:
            result = db.update(MyDatabaseInfo.MyTabInfo.TABNAME, values, null,
                    null);
            break;
        case GET_MEMBER_ITEM:
            result = db.update(MyDatabaseInfo.MyTabInfo.TABNAME, values,
                    whereSelection, whereArgs);
            break;
        default:
            db.close();
            throw new UnsupportedOperationException("不支持该操作！");
        }
        db.close();
        return result;
    }
}

4、写一个测试类继承与Activity，测试，我们的contentprovider 能否正常运行

package com.example.phonedemo;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.FrameLayout.LayoutParams;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.Toast;

import com.example.phonedemo.contentprovider.MyDatabaseInfo;

public class MyCPActivity extends Activity {

    private LayoutParams wrap_h = new LayoutParams(LayoutParams.WRAP_CONTENT,
            LayoutParams.WRAP_CONTENT);
    private LayoutParams wrap_v = new LayoutParams(LayoutParams.MATCH_PARENT,
            LayoutParams.WRAP_CONTENT);
    private LayoutParams match = new LayoutParams(LayoutParams.MATCH_PARENT,
            LayoutParams.MATCH_PARENT);

    private LinearLayout scream = null;
    private LinearLayout layout = null;
    private Button insertBut = null;
    private Button updateBut = null;
    private Button deleteBut = null;
    private Button queryBut = null;
    private ListView list = null;
    private ArrayAdapter<String> adapter = null;
    private List<String> contentList = new ArrayList<String>();

    public long insert(String name, int age, String email) {
        ContentResolver contentResolver = null;
        contentResolver = super.getContentResolver();
        ContentValues values = new ContentValues();
        values.put(MyDatabaseInfo.MyTabInfo.NAME, name);
        values.put(MyDatabaseInfo.MyTabInfo.AGE, age);
        values.put(MyDatabaseInfo.MyTabInfo.EMAIL, email);
        Uri uri = contentResolver.insert(MyDatabaseInfo.MyTabInfo.CONTENT_URI,
                values);
        return ContentUris.parseId(uri);
    }

    public long update(int id, String name, int age, String email) {
        int r = 0;
        ContentResolver result = super.getContentResolver();
        ContentValues values = new ContentValues();
        values.put(MyDatabaseInfo.MyTabInfo.NAME, name);
        values.put(MyDatabaseInfo.MyTabInfo.AGE, age);
        values.put(MyDatabaseInfo.MyTabInfo.EMAIL, email);
        if ("".equals(id) || 0 == id) {
            // 更新全部
            r = result.update(MyDatabaseInfo.MyTabInfo.CONTENT_URI, values,
                    null, null);
        } else {
            r = result.update(ContentUris.withAppendedId(
                    MyDatabaseInfo.MyTabInfo.CONTENT_URI, id), values,
                    " _id = ?", new String[] { String.valueOf(id) });
        }
        return r;
    }

    public int delelte(int id) {
        ContentResolver resolver = super.getContentResolver();
        int count = 0;
        if ("".equals(id) || 0 == id) {
            // 删除全部
            count = resolver.delete(MyDatabaseInfo.MyTabInfo.CONTENT_URI, null,
                    null);
        } else {
            // 根据传入的ID删除数据
            count = resolver.delete(ContentUris.withAppendedId(
                    MyDatabaseInfo.MyTabInfo.CONTENT_URI, id), "_id=?",
                    new String[] { String.valueOf(id) });
        }
        return count;
    };

    public List<String> query() {
        List<String> all = new ArrayList<String>();
        ContentResolver resolver = super.getContentResolver();
        Cursor cursor = resolver.query(MyDatabaseInfo.MyTabInfo.CONTENT_URI,
                null, null, null, null);
        for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {
            all.add("id: " + cursor.getInt(0) + ", name: "
                    + cursor.getString(1) + ", age: " + cursor.getInt(2));
        }
        System.out.println("** all.size(): " + all.size());
        return all;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        this.scream = new LinearLayout(this);
        this.scream.setOrientation(LinearLayout.VERTICAL);

        this.layout = new LinearLayout(this);
        this.layout.setOrientation(LinearLayout.HORIZONTAL);

        this.insertBut = new Button(this);
        this.insertBut.setText("增加");
        this.insertBut.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                int id = (int) MyCPActivity.this.insert("qinxijuan", 30,
                        "niitqin@163.com");
                Toast.makeText(MyCPActivity.this, "增加成功。id = " + id,
                        Toast.LENGTH_LONG).show();
            }
        });
        this.layout.addView(this.insertBut, wrap_h);

        this.updateBut = new Button(this);
        this.updateBut.setText("更新");
        this.updateBut.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                int id = (int) MyCPActivity.this.update(0, "qinxijuan", 18,
                        "rigoberto@126.com");
                Toast.makeText(MyCPActivity.this, "更新成功。id = " + id,
                        Toast.LENGTH_LONG).show();
            }
        });
        this.layout.addView(this.updateBut, wrap_h);

        this.deleteBut = new Button(this);
        this.deleteBut.setText("删除");
        this.deleteBut.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                int count = (int) MyCPActivity.this.delelte(0);
                Toast.makeText(MyCPActivity.this, "删除" + count + "条记录。",
                        Toast.LENGTH_LONG).show();
            }
        });
        this.layout.addView(this.deleteBut, wrap_h);

        this.queryBut = new Button(this);
        this.queryBut.setText("查询");
        this.queryBut.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                MyCPActivity.this.contentList = MyCPActivity.this.query();
                MyCPActivity.this.adapter = new ArrayAdapter<String>(MyCPActivity.this,
                        android.R.layout.simple_list_item_1,
                        MyCPActivity.this.contentList);
                MyCPActivity.this.list.setAdapter(adapter);
            }
        });
        this.layout.addView(this.queryBut, wrap_h);

        this.scream.addView(this.layout, wrap_v);

        this.list = new ListView(this);
        this.adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, this.contentList);
        this.list.setAdapter(adapter);
        this.scream.addView(this.list, this.wrap_v);
        super.addContentView(scream, match);
    }

}

5、需要在自己的应用的AndroidMainiFest.xml文件中开放自己的ContnetProvider，并设置read/write权限，这样其他应用才能访问该应用的数据。

        <provider
            android:name=".contentprovider.MyContentProvider"
            android:authorities="com.example.phonedemo.contentprovider"
            android:readPermission="com.example.phonedemo.contentprovider.READ_PERMISSON"
            android:writePermission="com.example.phonedemo.contentprovider.WRITE_PERMISSON" />