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

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:onClick="search"
	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;

	}

}

<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:onClick="search"
        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>