我想在一个扩展线程中进行我的数据库操作，所以首先我制作一个ThreadLooper用于发布的Runnables，用于启动数据库操作的。
它看起来像这样：
import android.os.Handler;
import android.os.Handler.Callback;
import android.os.HandlerThread;
import android.os.Message;
/**
* @author
* @version 1.0 This class is used as ThreadLooper to make the database
* operation CRUD , this looper is singlton across the app
*
*/
public class DBThreadLooper extends HandlerThread {
public Handler mHandler;
private DBThreadLooper(String name) {
super(name);
}
private static DBThreadLooper mInstance;
public static DBThreadLooper newInstance() {
if (mInstance == null) {
mInstance = new DBThreadLooper("DATA BASE THREAD LOOPER ");
mInstance.start();
}
return mInstance;
}
@Override
public synchronized void start() {
super.start();
waitUntilReady();
}
private void waitUntilReady() {
mHandler = new Handler(getLooper(), new Callback() {
public boolean handleMessage(Message msg) {
return true;
}
});
}
@Override
protected Object clone() throws CloneNotSupportedException {
throw new CloneNotSupportedException();
}
}
现在我有这个方法可以进行数据库操作
private void handleFavButton() {
int index = viewPager.getCurrentItem();
Cursor c = mAdapter.getAdapterCursor();
c.moveToPosition(index);
final String quote_id = c.getString(c.getColumnIndex(QuoteTableMetaData._ID));
final int is_fav = c.getInt(c.getColumnIndex(QuoteTableMetaData.C_IS_FAVORITE));
if(is_fav == 0){
DBThreadLooper looper = DBThreadLooper.newInstance();
looper.mHandler.post(new Runnable() {
public void run() {
//1. make it 1
QuoteTableMetaData qTable = QuoteTableMetaData
.getInstance();
ContentValues values = new ContentValues();
values.put(QuoteTableMetaData.C_IS_FAVORITE, new Integer(1));
qTable.update(DBUtils.getDBHelper(getApplicationContext())
.getWritableDatabase(), values,
QuoteTableMetaData._ID + "= ?",
new String[] { quote_id });
//2. insert a new record in Fav Table with the id
FavouriteQuoteTable fTable = FavouriteQuoteTable
.getInstance();
values.clear();
values.put(FavouriteQuoteTable.C_QUOTE_ID, quote_id);
fTable.insert(DBUtils.getDBHelper(getApplicationContext())
.getWritableDatabase(), null, values);
}
});
}
else{
DBThreadLooper looper = DBThreadLooper.newInstance();
looper.mHandler.post(new Runnable() {
public void run() {
//1.make it 0
QuoteTableMetaData qTable = QuoteTableMetaData
.getInstance();
ContentValues values = new ContentValues();
values.put(QuoteTableMetaData.C_IS_FAVORITE, new Integer(0));
qTable.update(DBUtils.getDBHelper(getApplicationContext())
.getWritableDatabase(), values,
QuoteTableMetaData._ID + "=?",
new String[] { quote_id });
// 2. delete record with id from fav Table
FavouriteQuoteTable fTable = FavouriteQuoteTable
.getInstance();
fTable.delete(DBUtils.getDBHelper(getApplicationContext())
.getWritableDatabase(),
FavouriteQuoteTable.C_QUOTE_ID + "=?",
new String[] { quote_id });
}
});
}
我是否需要在方法中制作quote_idand ，这样我的方法就不会遇到同步问题。is_favvolatile