我在空對象引用上嘗試調用虛擬方法void android.widget.TextView.setText(java.lang.CharSequence)'
時收到空指針豁免錯誤。無法將雙精度值作爲字符串轉換爲textview
public class MainActivity {
TextView servingqueue;
}
這是的onCreate
DatabaseReference mRootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference mServingQueue = mRootRef.child("ServingQueue");
servingqueue = (TextView) findViewById(R.id.queueServing);
mServingQueue.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Double number = dataSnapshot.getValue(Double.class);
servingqueue.setText(String.valueOf(number));
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
錯誤權出現在
servingqueue.setText(String.valueOf(number));
它只是不希望從火力地堡值傳遞給我的TextView。加載活動後,我的應用程序即將關閉。
是它'servingqueue'或'mServingQueue'? – nandsito
'mServinQueue'引用了我以前的代碼,它是 'DatabaseReference mServingQueue = mRootRef.child(「ServingQueue」);' –
異常堆棧跟蹤? –