Android-小项目之迷你英文词典-使用existing sqlite database-github第三库android-sqlite-asset-help

kinght2008

　　将已有的词典数据库文件，用到项目中
　　谷歌搜索“android existing sqlite database”
　　http://stackoverflow.com/questions/1951805/how-to-access-an-existing-sqlite-database-in-android

　　通常来说，

SQLiteDatabase db = SQLiteDatabase.openDatabase(path, null, 0);
　　就可以。
　　但是，如果 数据库文件在 assets 目录下，该如何做呢？
　　http://stackoverflow.com/questions/513084/how-to-ship-an-android-application-with-a-database

　　哈，用第三方库：
　　https://github.com/jgilfelt/android-sqlite-asset-helper

　　OK直接看项目吧：

　　

　　数据库文件：

　　运行效果图：

　　

　　

　　代码：

package com.jiangge.dictmini;
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends Activity {
private EditText mEditText; //输入框
private TextView mReslutView; //显示查询结果
private Cursor resultCursor;
private MyDatabase db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mEditText = (EditText) findViewById(R.id.et_words);
mReslutView = (TextView) findViewById(R.id.tv_result);
}
//搜索按钮响应事件，方法在 xml 文件中定义 android:
public void search(View view){
String inputValue = mEditText.getText().toString().trim();
if (TextUtils.isEmpty(inputValue)) {
mReslutView.setText("查询内容不能为空");
return;
}
db = new MyDatabase(MainActivity.this);
resultCursor = db.getResultFromDB(inputValue);
if (resultCursor != null && resultCursor.getCount() > 0) {
resultCursor.moveToFirst();
String value = resultCursor.getString(resultCursor.getColumnIndex("chinese" ));
mReslutView.setText(value);
}else {
mReslutView.setText("查询结果不存在");
}
}
}



　　File:MyDatabase.java 根据第三方库修改而成

package com.jiangge.dictmini;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteQueryBuilder;
import com.readystatesoftware.sqliteasset.SQLiteAssetHelper;
public class MyDatabase extends SQLiteAssetHelper {
private static final String DATABASE_NAME = "dictionary";
private static final int DATABASE_VERSION = 1;
public MyDatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
// you can use an alternate constructor to specify a database location
// (such as a folder on the sd card)
// you must ensure that this folder is available and you have permission
// to write to it
//super(context, DATABASE_NAME, context.getExternalFilesDir(null).getAbsolutePath(), null, DATABASE_VERSION);
}
public Cursor getResultFromDB(String value) {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String [] sqlSelect = {"english", "chinese"};
String sqlTables = "t_words"; //select * from t_words where english = 'love'
qb.setTables(sqlTables);
Cursor cursor = qb.query(db, sqlSelect, "english=?", new String[]{value}, null, null, null);
cursor.moveToFirst();
return cursor;
}
}

　　

　　


布局文件：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="@+id/btn_search"
android:
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="@+id/et_words"
android:text="查询" />
<EditText
android:id="@+id/et_words"
android:hint="请输入要查询的单词"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginTop="0dp"
android:layout_toLeftOf="@+id/btn_search"
android:ems="10" />
<TextView
android:id="@+id/tv_desc"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/et_words"
android:layout_below="@+id/et_words"
android:text="显示结果" />
<TextView
android:id="@+id/tv_result"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/tv_desc"
android:layout_below="@+id/tv_desc"
android:layout_marginTop="18dp"
android:textAppearance="?android:attr/textAppearanceMedium" />
</RelativeLayout>