我有这个应用程序，当调用MainActivity时，文本视图将显示当前数据信息或更确切地说是分数，如果COL1（星号）为空，则应在列星中写入0。然后当播放并达到分数应该改变的时候，比如添加分数，它应该覆盖列中的数据。
这是我的DatabaseHelper的代码
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "star.db";
public static final String TABLE_NAME = "stars_table";
public static final String COL1 = "stars";
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table" + TABLE_NAME + "("+COL1+")");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS" + TABLE_NAME);
onCreate(db);
}
public boolean insertData(Integer stars){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL1, stars);
long result = db.insert(TABLE_NAME, null, contentValues);
if(result == -1)
return false;
else
return true;
}
public Cursor getAllData(){
SQLiteDatabase db = this.getWritableDatabase();
Cursor res = db.rawQuery("select stars from" + TABLE_NAME, null);
return res;
}
}
那么如何在textview中显示它，以及如何读取数据，计算，然后用新数据覆盖它？
至于我的MainActivity
public class MainActivity extends Activity {
private static TextView txt_stars;
DatabaseHelper mydb;
@
Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
onButtonClickListener();
mydb = new DatabaseHelper(this);
txt_stars = (TextView) findViewById(R.id.txtStars);
//this where the score will show
}
public void onButtonClickListener() {
//some buttons
//game start
}
}
至于将计算答案是否正确的活动
public class OneFifteenActivity extends Activity {
private static Button button_next;
private static TextView txt_ans;
final Context context = this;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.one_fifteen);
onButtonClickListener();
}
public void onButtonClickListener() {
txt_ans = (EditText) findViewById(R.id.edittxtAns);
button_next = (Button) findViewById(R.id.btnNext);
button_next.setOnClickListener(
new View.OnClickListener() {@
Override
public void onClick(View v) {
if (txt_ans.getText().toString().equals("dai")) {
AlertDialog.Builder alert = new AlertDialog.Builder(context);
alert.setMessage("Message here");
alert.setCancelable(false);
alert.setPositiveButton("next", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
Intent nextForm = new Intent(".MainActivity");
startActivity(nextForm);
//computation here
}
});
AlertDialog alertDialog = alert.create();
alertDialog.show();
} else {
AlertDialog.Builder alert = new AlertDialog.Builder(context);
alert.setMessage("Message here");
alert.setCancelable(false);
alert.setPositiveButton("next", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
AlertDialog.Builder alert = new AlertDialog.Builder(context);
alert.setTitle("Congratulations!");
alert.setMessage("You have earned 50 stars");
alert.setCancelable(false);
alert.setPositiveButton("next", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
Intent nextForm = new Intent(".MainActivity");
startActivity(nextForm);
}
});
AlertDialog alertDialog = alert.create();
alertDialog.show();
}
});
AlertDialog alertDialog = alert.create();
alertDialog.show();
}
}
}
);
}
}
我已经被困在这里好几个星期，有人能帮助我吗？
非常感谢。
答案 0 :(得分：1)
我认为更新你的表并添加点你可以创建一个与此类似的功能“添加点”：
public void _addPoints(){
db.rawQuery("UPDATE ? FROM "+TABLE_NAME+" SET ?=?+1", new String[]{COL1, COL1, COL1}); //Here I don't know if you have multiple users or players where this query must be used, if there are
please add the needed WHERE x=y and subsitute the 1 for your desired increase value.
}
现在要在textView中显示你必须读取的值，你可以创建一个返回星数的函数：
Cursor c=db.query(TABLE_NAME, COL1, null, null, null, null); //if you have only 1 player, if you have more you must fill the WHERE parameters (check API for that).
c.moveToNext();
int points=c.getInt(0); //or anything else you need
return points;
然后设置textView文本：
txt_stars.setText(Integer.toString(points));
如果这有帮助，请告诉我，也许我并不理解这个问题。
答案 1 :(得分：1)
根据您的要求，要使DatabaseHelper类成为子类，您可以这样继续：
class Functions{
public update (){
//the update code I already provided
}
class DatabaseHelper extends SQLiteOpenHelper{
//the code of your databaseHelper
}
}
正如您所看到的，DatabaseHelper类位于Function类中，称为子类，它的优点是您可以使用所有变量（即使它们是私有的）在Functions类中执行您想要的任何功能。除了Functions类之外，DatabaseHelper类的函数和类DatabseHelper不能在程序中的任何其他地方使用。
答案 2 :(得分：0)
Loader类将监视您的数据源并提供新结果。如果你实施
LoaderManager.LoaderCallbacks<Cursor>
接口，您将能够从传递给onLoadFinished覆盖方法的光标获取数据，并从那里更新TextViews。
http://www.vogella.com/tutorials/AndroidSQLite/article.html#loader_definition
答案 3 :(得分：0)
查看一些可以使用此代码的信息：
private String[] checkAll(){
String tam[] = new String[5];
Cursor cursor = db.rawQuery("select * from " + TABLE_NAME, null);
if (cursor.getCount() != 0) {
if (cursor.moveToFirst()) {
do {
tam[0] = cursor.getString(cursor
.getColumnIndex("_id"));
tam[1] = cursor.getString(cursor
.getColumnIndex("column1Name"));
tam[2] = cursor.getString(cursor
.getColumnIndex("column2Name"));
tam[3] = cursor.getString(cursor
.getColumnIndex("column3Name"));
tam[4] = cursor.getString(cursor
.getColumnIndex("column4Name"));
} while (cursor.moveToNext());
}
} else {
// Toast.makeText(getApplicationContext(), "No data", Toast.LENGTH_LONG).show();
}
cursor.close();
return tam;
}// checkAll
然后在你的主动或任何你想要的地方
String arrray[] = checkAll();
textview.setText(arrray[SomePosition]);
Toast.makeText(getApplicationContext,"HERE IS A MESSAGE TO THE USER "+arrray[SomePosition], Toast.LENGTH_LONG).show();
最后，如果你想更新，请使用：
String[] args = new String[]{"1"}; // String to complete the condition(where)
db.execSQL("UPDATE " + TABLE_NAME + " SET Column1Name='" + someVariable + "', Column2Name='"+SomeOtherVariable+"' WHERE idNameColumn=?", args);