How to call the added QWidget of QGridLayout.

Hi, ALL.

I 'm tired call the added QWidget of QGridLayout.

How I can call the added QWidget of QGridLayout?

follow the source.

qDebug() is print 0.

Code:

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grid = new QGridLayout;
		for (j=0; j<i; j++) {
			label = new QLabel(QString("Index %1").arg(j+1));
			ed = new QLineEdit;
			grid->addWidget(label, j, 0);
			grid->addWidget(ed,    j, 1);
		}
		b = new QPushButton("Put");
		grid->addWidget(b, i, 0, 1, 2);
 
		QList<QPushButton *> allPButtons = qFindChildren<QPushButton*> ( grid );  //grid->findChildren<QPushButton *>();
		QList<QLabel *> allLabel = qFindChildren<QLabel*> ( grid );          // grid->findChildren<QLabel *>();
		QList<QLineEdit *> allLine = qFindChildren<QLineEdit*> ( grid );       // grid->findChildren<QLineEdit *>();
 
		qDebug() << "label count : " << allLabel.count();
		qDebug() << "QLineEdit count : " << allLine.count();
 
		for (j=0; j<allPButtons.count(); j++) {
			delete allPButtons[j];
		}
		for (j=0; j<allLabel.count(); j++) {
			delete allLabel[j];
		}
		for (j=0; j<allLine.count(); j++) {
			delete allLine[j];
		}

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