sqlite实例

代码   
package com.webabcd.SQLite;  
 
import android.content.Context;  
import android.database.sqlite.SQLiteDatabase;  
import android.database.sqlite.SQLiteOpenHelper;  
import android.database.sqlite.SQLiteDatabase.CursorFactory;  
 
// 数据库操作的 Helper 类  
public class DatabaseHelper extends SQLiteOpenHelper {  
 
    DatabaseHelper(Context context, String name, CursorFactory cursorFactory, int version) {  
        super(context, name, cursorFactory, version);  
    }  
 
    @Override 
    public void onCreate(SQLiteDatabase db) {  
        // TODO 创建数据库后，对数据库的操作  
    }  
 
    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {  
        // TODO 更改数据库版本的操作  
    }  
 
    @Override 
    public void onOpen(SQLiteDatabase db) {  
        super.onOpen(db);  
          
        // TODO 每次成功打开数据库后首先被执行  
    }  
}  
 
 
Main.java  
 
代码   
package com.webabcd.SQLite;  
 
import java.util.Random;  
 
import android.app.Activity;  
import android.content.ContentValues;  
import android.database.Cursor;  
import android.database.SQLException;  
import android.database.sqlite.SQLiteDatabase;  
import android.os.Bundle;  
import android.view.View;  
import android.widget.Button;  
import android.widget.TextView;  
 
public class Main extends Activity {  
 
    private DatabaseHelper dbHelper;  
 
    private static final String DATABASE_NAME = "db.db";  
    private static final int DATABASE_VERSION = 1;  
    private static final String TABLE_NAME = "employee";  
 
    TextView txtMsg;  
 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
 
        dbHelper = new DatabaseHelper(this, DATABASE_NAME, null,  
                DATABASE_VERSION);  
 
        txtMsg = (TextView) this.findViewById(R.id.txtMsg);  
 
        Button btn1 = (Button) this.findViewById(R.id.btn1);  
        btn1.setText("创建表");  
        btn1.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                CreateTable();  
            }  
        });  
 
        Button btn2 = (Button) this.findViewById(R.id.btn2);  
        btn2.setText("插入 3 条记录");  
        btn2.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                insertItem();  
            }  
        });  
 
        Button btn3 = (Button) this.findViewById(R.id.btn3);  
        btn3.setText("删除全部记录");  
        btn3.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                deleteItem();  
            }  
        });  
 
        Button btn4 = (Button) this.findViewById(R.id.btn4);  
        btn4.setText("更新指定数据");  
        btn4.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                updateItem();  
            }  
        });  
 
        Button btn5 = (Button) this.findViewById(R.id.btn5);  
        btn5.setText("显示全部数据");  
        btn5.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                showItems();  
            }  
        });  
 
        Button btn6 = (Button) this.findViewById(R.id.btn6);  
        btn6.setText("删除表");  
        btn6.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                dropTable();  
            }  
        });  
    }  
 
    // 创建数据表  
    private void CreateTable() {  
        SQLiteDatabase db = dbHelper.getWritableDatabase();  
        String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME  
                + " (ID INTEGER PRIMARY KEY, Name VARCHAR, Age INTEGER);";  
        try {  
            db.execSQL(sql);  
            txtMsg.append("数据表成功创建/n");  
        } catch (SQLException ex) {  
            txtMsg.append("数据表创建错误/n" + ex.toString() + "/n");  
        }  
    }  
 
    // 插入数据  
    private void insertItem() {  
        SQLiteDatabase db = dbHelper.getWritableDatabase();  
          
        try {  
            Random random = new Random();  
            for (int i = 0; i < 3; i++) {  
                String sql = "insert into " + TABLE_NAME  
                        + " (name, age) values ('name" + String.valueOf(i)  
                        + "', " + random.nextInt() + ")";  
                // execSQL() - 执行指定的 sql  
                db.execSQL(sql);  
            }  
            txtMsg.append("成功插入 3 条数据/n");  
        } catch (SQLException ex) {  
            txtMsg.append("插入数据失败/n" + ex.toString() + "/n");  
        }  
    }  
 
    // 删除数据  
    private void deleteItem() {  
        try {  
            SQLiteDatabase db = dbHelper.getWritableDatabase();  
            db.delete(TABLE_NAME, " id < 999999", null);  
            txtMsg.append("成功删除数据/n");  
        } catch (SQLException e) {  
            txtMsg.append("删除数据失败/n");  
        }  
    }  
 
    // 更新数据  
    private void updateItem() {  
        SQLiteDatabase db = dbHelper.getWritableDatabase();  
 
        try {  
            ContentValues values = new ContentValues();  
            values.put("name", "批量更新后的名字");  
 
            db.update(TABLE_NAME, values, "id             txtMsg.append("成功更新数据/n");  
        } catch (SQLException e) {  
            txtMsg.append("更新数据失败/n");  
        }  
    }  
 
    // 查询数据  
    private void showItems() {  
        SQLiteDatabase db = dbHelper.getReadableDatabase();  
 
        try {  
            String[] column = { "id", "name", "age" };  
            Cursor cursor = db.query(TABLE_NAME, column, null, null, null,  
                    null, null);  
            Integer num = cursor.getCount();  
            txtMsg.append("共 " + Integer.toString(num) + " 条记录/n");  
            cursor.moveToFirst();  
 
            while (cursor.getPosition() != cursor.getCount()) {  
                txtMsg.append(Integer.toString(cursor.getPosition()) + "," 
                        + String.valueOf(cursor.getString(0)) + "," 
                        + cursor.getString(1) + "," 
                        + String.valueOf(cursor.getString(2)) + "/n");  
                cursor.moveToNext();  
            }  
        } catch (SQLException ex) {  
            txtMsg.append("读取数据失败/n" + ex.toString() + "/n");  
        }  
    }  
 
    // 删除数据表  
    private void dropTable() {  
        SQLiteDatabase db = dbHelper.getWritableDatabase();  
        String sql = "DROP TABLE IF EXISTS " + TABLE_NAME;  
        try {  
            db.execSQL(sql);  
            txtMsg.append("数据表删除成功/n");  
        } catch (SQLException ex) {  
            txtMsg.append("数据表删除错误/n" + ex.toString() + "/n");  
        }  
    }  
}  
 
 
2、ContentProvider 的 Demo  
MyUser.java  
 
代码   
package com.webabcd.contentprovider;  
 
import android.net.Uri;  
import android.provider.BaseColumns;  
 
// 自定义 ContentProvider 所需的实体类  
public class MyUser {  
 
    // 必须要有 _id 字段。本例中 BaseColumn 类中已经包含了 _id 字段  
    public static final class User implements BaseColumns {  
          
        // 定义 CONTENT_URI  
        public static final Uri CONTENT_URI = Uri.parse("content://com.webabcd.MyContentProvider");  
 
        // 表数据列  
        public static final String USER_NAME = "USER_NAME";  
    }  
}  
 
 
MyContentProvider.java  
 
代码   
package com.webabcd.contentprovider;  
 
import java.io.File;  
import java.io.FileInputStream;  
import java.io.FileOutputStream;  
 
import org.apache.http.util.EncodingUtils;  
 
import android.content.ContentProvider;  
import android.content.ContentUris;  
import android.content.ContentValues;  
import android.database.Cursor;  
import android.database.MatrixCursor;  
import android.net.Uri;  
 
// 继承 ContentProvider 以实现自定义的 ContentProvider（基于文件的信息存储）  
public class MyContentProvider extends ContentProvider {  
 
    private File file;  
    private FileOutputStream out;  
    private FileInputStream in;  
 
    // ContentProvider 的删除数据接口  
    @Override 
    public int delete(Uri uri, String selection, String[] selectionArgs) {  
        // TODO Auto-generated method stub  
        return 0;  
    }  
 
    @Override 
    public String getType(Uri uri) {  
        // TODO Auto-generated method stub  
        return null;  
    }  
 
    // ContentProvider 的插入数据接口   
    @Override 
    public Uri insert(Uri uri, ContentValues values) {  
 
        try {  
            out = new FileOutputStream(file);  
            out.write(values.getAsString(MyUser.User.USER_NAME).getBytes());  
            out.close();  
 
            int rowId = 0;  
            Uri rowUri = ContentUris.appendId(  
                    MyUser.User.CONTENT_URI.buildUpon(), rowId).build();  
            getContext().getContentResolver().notifyChange(rowUri, null);  
 
            return rowUri;  
        } catch (Exception e) {  
            return null;  
        }  
    }  
 
    // 创建用于保存信息的文件  
    @Override 
    public boolean onCreate() {  
        try {  
            // 每个包中应用程序的私有目录为：/data/data/包名/  
            // SD 卡目录为：/sdcard  
            file = new File("/data/data/com.webabcd.contentprovider/",  
                    "demo.txt");  
            if (!file.exists())  
                file.createNewFile();  
 
            return true;  
        } catch (Exception ex) {  
            return false;  
        }  
    }  
 
    // ContentProvider 的查询数据接口  
    @Override 
    public Cursor query(Uri uri, String[] projection, String selection,  
            String[] selectionArgs, String sortOrder) {  
          
        String content;  
 
        try {  
            in = new FileInputStream(file);  
            int length = (int) file.length();  
            byte[] buffer = new byte[length];  
            in.read(buffer, 0, length);  
            content = EncodingUtils.getString(buffer, "UTF-8");  
            in.close();  
 
            String[] columns = new String[] { MyUser.User._ID, MyUser.User.USER_NAME };  
            MatrixCursor cur = new MatrixCursor(columns);  
            String[] values = new String[] { "0", content };  
            cur.moveToFirst();  
            cur.addRow(values);  
 
            return cur;  
        } catch (Exception e) {  
            return null;  
        }  
    }  
 
    // ContentProvider 的更新数据接口  
    @Override 
    public int update(Uri uri, ContentValues values, String selection,  
            String[] selectionArgs) {  
        // TODO Auto-generated method stub  
        return 0;  
    }  
}  
 
 
Main.java  
 
代码   
package com.webabcd.contentprovider;  
 
import java.util.Random;  
 
import android.app.Activity;  
import android.content.ContentUris;  
import android.content.ContentValues;  
import android.database.Cursor;  
import android.net.Uri;  
import android.os.Bundle;  
import android.provider.Contacts;  
import android.provider.Contacts.People;  
import android.util.Log;  
import android.view.View;  
import android.widget.Button;  
import android.widget.Toast;  
 
/* 
 * 几个常用的系统内置的 ContentProvider 如下：  
 * content://media/internal/images  这个URI将返回设备上存储的所有图片 
 * content://contacts/people/ 这个URI将返回设备上的所有联系人信息 
 * content://contacts/people/45 这个URI返回单个结果（联系人信息中ID为45的联系人记录） 
 */ 
public class Main extends Activity {  
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
 
        Button btn1 = (Button) this.findViewById(R.id.btn1);  
        btn1.setText("新增联系人记录");  
        btn1.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                Random random = new Random();  
                insertRecords("name" + String.valueOf(random.nextInt()), String  
                        .valueOf(random.nextInt()));  
            }  
        });  
 
        Button btn2 = (Button) this.findViewById(R.id.btn2);  
        btn2.setText("查看联系人记录");  
        btn2.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                displayRecords();  
            }  
        });  
 
        Button btn3 = (Button) this.findViewById(R.id.btn3);  
        btn3.setText("清除联系人记录");  
        btn3.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                deleteRecords();  
            }  
        });  
 
        Button btn4 = (Button) this.findViewById(R.id.btn4);  
        btn4.setText("更新联系人记录");  
        btn4.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                // 此处只是演示，id 来自 People._ID ，可参见 displayRecords() 是如何获取 id 的  
                int id = 0;  
                updateRecord(id, "修改后的name");  
            }  
        });  
 
        Button btn5 = (Button) this.findViewById(R.id.btn5);  
        btn5.setText("新增记录到 MyContentProvider");  
        btn5.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                insertRecord2MyContentProvider("webabcd");  
            }  
        });  
 
        Button btn6 = (Button) this.findViewById(R.id.btn6);  
        btn6.setText("获取记录从 MyContentProvider");  
        btn6.setOnClickListener(new Button.OnClickListener() {  
            public void onClick(View v) {  
                displayRecord2MyContentProvider();  
            }  
        });  
    }  
 
    // 调用 ContentProvider 的插入接口  
    private void insertRecords(String name, String phoneNum) {  
        ContentValues values = new ContentValues();  
        values.put(People.NAME, name);  
        Uri uri = getContentResolver().insert(People.CONTENT_URI, values);  
        Log.d("MyDebug", uri.toString());  
        Uri numberUri = Uri.withAppendedPath(uri,  
                People.Phones.CONTENT_DIRECTORY);  
        Log.d("MyDebug", numberUri.toString());  
 
        values.clear();  
        values.put(Contacts.Phones.TYPE, People.Phones.TYPE_MOBILE);  
        values.put(People.NUMBER, phoneNum);  
        getContentResolver().insert(numberUri, values);  
    }  
 
    // 调用 ContentProvider 的查询接口  
    private void displayRecords() {  
        String[] columns = new String[] { People._ID, People.NAME,  
                People.NUMBER };  
        Uri contacts = People.CONTENT_URI;  
        Log.d("MyDebug", contacts.toString());  
        Cursor cur = managedQuery(contacts, columns, // 要返回的数据字段  
                null, // WHERE子句  
                null, // WHERE 子句的参数  
                null // Order-by子句  
        );  
 
        if (cur.moveToFirst()) {  
            String id = null;  
            String name = null;  
            String phoneNo = null;  
            while (cur.getPosition() != cur.getCount()) {  
                id = cur.getString(cur.getColumnIndex(People._ID));  
                name = cur.getString(cur.getColumnIndex(People.NAME));  
                phoneNo = cur.getString(cur.getColumnIndex(People.NUMBER));  
 
                Toast.makeText(this, id + " / " + name + " / " + phoneNo,  
                        Toast.LENGTH_SHORT).show();  
                cur.moveToNext();  
            }  
        }  
    }  
 
    // 调用 ContentProvider 的删除接口  
    private void deleteRecords() {  
        Uri uri = People.CONTENT_URI;  
        Log.d("MyDebug", uri.toString());  
        getContentResolver().delete(uri, null, null);  
        // getContentResolver().delete(uri, "NAME=" + "'name'", null);  
    }  
 
    // 调用 ContentProvider 的更新接口  
    private void updateRecord(int recordNo, String name) {  
        Uri uri = ContentUris.withAppendedId(People.CONTENT_URI, recordNo);  
        Log.d("MyDebug", uri.toString());  
        ContentValues values = new ContentValues();  
        values.put(People.NAME, name);  
        getContentResolver().update(uri, values, null, null);  
    }  
 
      
    // 调用自定义 ContentProvider 的插入接口  
    private void insertRecord2MyContentProvider(String name) {  
        ContentValues values = new ContentValues();  
        values.put(MyUser.User.USER_NAME, name);  
        getContentResolver().insert(MyUser.User.CONTENT_URI, values);  
 
    }  
 
    // 调用自定义 ContentProvider 的查询接口  
    private void displayRecord2MyContentProvider() {  
        String[] columns = new String[] { MyUser.User.USER_NAME };  
        Uri uri = MyUser.User.CONTENT_URI;  
        Cursor cur = managedQuery(uri, columns, null, null, null);  
 
        while (cur.getPosition() != cur.getCount()) {  
            String id = cur.getString(cur.getColumnIndex(People._ID));  
            String name = cur.getString(cur.getColumnIndex(MyUser.User.USER_NAME));  
            Toast.makeText(this,  
                    id + " / " + name,  
                    Toast.LENGTH_SHORT).show();  
            cur.moveToNext();  
        }  
    }  
}  
 
AndroidManifest.xml  
 
代码   
  
      package="com.webabcd.contentprovider" 
      android:versionCode="1" 
      android:versionName="1.0">  
      
                          android:label="@string/app_name">