android数据储存和访问-书记的增删改查

MainActivity代码如下：

package com.example.databasetest;

import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

private MyDatabaseHelper dbHelper;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dbHelper = new MyDatabaseHelper(this, "BookStore.db", null, 2);

/* 创建数据 */
Button createDatabase = (Button) findViewById(R.id.create_database);
createDatabase.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
dbHelper.getWritableDatabase();
}
});

/* 添加数据 */
Button addData = (Button) findViewById(R.id.add_data);
addData.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
// 开始组装第一条数据
values.put("name", "The Da Vinci Code");
values.put("author", "Dan Brown");
values.put("pages", 454);
values.put("price", 16.96);
db.insert("Book", null, values); // 插入第一条数据
values.clear();
// 开始组装第二条数据
values.put("name", "The Lost Symbol");
values.put("author", "Dan Brown");
values.put("pages", 510);
values.put("price", 19.95);
db.insert("Book", null, values); // 插入第二条数据
}
});

/* 更新数据 */
Button updateData = (Button) findViewById(R.id.update_data);
updateData.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("price", 10.99);
db.update("Book", values, "name = ?",
new String[] { "The Da Vinci Code" });
}
});

/* 删除数据 */
Button deleteButton = (Button) findViewById(R.id.delete_data);
deleteButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
db.delete("Book", "pages > ?", new String[] { "500" });
}
});

/* 查询数据 */
Button queryButton = (Button) findViewById(R.id.query_data);
queryButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
// 查询Book表中所有的数据
Cursor cursor = db.query("Book", null, null, null, null, null,
null);
if (cursor.moveToFirst()) {
do {
// 遍历Cursor对象，取出数据并打印
String name = cursor.getString(cursor
.getColumnIndex("name"));
String author = cursor.getString(cursor
.getColumnIndex("author"));
int pages = cursor.getInt(cursor
.getColumnIndex("pages"));
double price = cursor.getDouble(cursor
.getColumnIndex("price"));
Log.d("MainActivity", "book name is " + name);
Log.d("MainActivity", "book author is " + author);
Log.d("MainActivity", "book pages is " + pages);
Log.d("MainActivity", "book price is " + price);
} while (cursor.moveToNext());
}
cursor.close();
}
});
}

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<Button
android:id="@+id/create_database"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Create database" />

<Button
android:id="@+id/add_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add data" />

<Button
android:id="@+id/update_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Update data" />

<Button
android:id="@+id/delete_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Delete data" />

<Button
android:id="@+id/query_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Query data" />

</LinearLayout>