在做城市搜索，此時，需要數據庫，可數據源從何處獲得？
1.新建一個.txt文件，以固定格式存儲城市數據，如：
1||北京
2||天津
3|新疆|烏魯木齊
4|新疆|奎屯
5|新疆|伊犁
6|新疆|庫爾勒
7|新疆|阿克蘇
8|青海省|西寧
9|河北省|石家莊
10|河北省|邯鄲
11|河北省|保定
第一個字段爲_id，第二個爲provience，第三個字段爲city
2.建數據庫
public void onCreate(SQLiteDatabase db) {
Log.d("DatabaseHelper","oncreat database-----------------------------------------");
db.execSQL("CREATE TABLE "+ CITY_TABLE + " ("+
"_id INTEGER PRIMARY KEY , "+
"province TEXT, " +
"city TEXT);");
}
到系統的/data/data目錄下的對應包下查看一下是否數據庫已建好。
3.將.txt數據導入到數據庫下
將.txt文件放到應用程序對應的databases目錄下
adb push ~/桌面/city.txt /data/data/com.android.weather/databases
# cd /data/data/com.android.weather/databases
# ls
city.txt
city_search.db
# sqlite3 city_search.db
sqlite> .tables
android_metadata citytable
sqlite> .import city.txt citytable
adb pull /data/data/com.android.weather/databases/city_search.db ~/桌面
現在已經獲取了一個city_search.db的文件在桌面上。
package com.android.weather.db;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.net.Uri;
import android.util.Log;
import com.android.weather.R;
public class CityDataProvider extends ContentProvider {
private static final String TAG = "CityDataProvider";
private static final String AUTHORITY = "com.android.weather.db.city";
private DatabaseHelper mDatabase;
public static final Uri CONTENT_URI = Uri.parse("content://"+AUTHORITY+"/city");
private final static String dataBaseDesDir = "/data/data/com.android.weather/databases";
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
Log.d(TAG,"query");
SQLiteDatabase db = mDatabase.getReadableDatabase();
return db.query(DatabaseHelper.CITY_TABLE, projection, selection, selectionArgs, null, null, null);
}
public boolean onCreate() {
mDatabase = DatabaseHelper.getInstance(getContext());
onCreateDatabaseDir();
return true;
}
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
return 0;
}
public int delete(Uri uri, String selection, String[] selectionArgs) {
return 0;
}
public String getType(Uri uri) {
return null;
}
public Uri insert(Uri uri, ContentValues values) {
return null;
}
private static class DatabaseHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "city_search.db";
private static final String CITY_TABLE = "citytable";
private static final int DATABASE_VERSION =4;
static synchronized DatabaseHelper getInstance(Context context) {
return new DatabaseHelper(context);
}
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase db) {
Log.d("DatabaseHelper","oncreat database-----------------------------------------");
// db.execSQL("CREATE TABLE "+ CITY_TABLE + " ("+
// "_id INTEGER PRIMARY KEY , "+
// "province TEXT, " +
// "city TEXT);");
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int currentVersion) {
// db.execSQL("DROP TABLE IF EXISTS "+CITY_TABLE);
// onCreate(db);
}
}
private void onCreateDatabaseDir() {
File dir = new File(dataBaseDesDir);
if (!dir.exists()) {
try {
dir.mkdir();
} catch (Exception e) {
e.printStackTrace();
}
}
copyDatabaseFile(dataBaseDesDir);
}
private void copyDatabaseFile(String destDir) {
File dest = new File(destDir+"/"+DatabaseHelper.DATABASE_NAME);
if(dest.exists())
{
return ;
}
try {
Log.d(TAG,"the database is not exit,then copy it---------------------");
InputStream in = CityDataProvider.this.getContext().getResources().openRawResource(R.raw.city_search);
int size = in.available();
byte buf[] = new byte[size];
in.read(buf);
in.close();
FileOutputStream out = new FileOutputStream(dest);
out.write(buf);
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}