所以我正在制作一个应用程序,用一个片段上的按钮输入信息,然后将信息发送回活动,并用另一个片段替换片段,以显示检索到的信息从第一个片段。但是,我收到一个错误:“com.example.cribbage2.CardKeyboardFrag不能转换为com.example.cribbage2.PCResultsFrag”,我不知道为什么。“无法投射到”带有碎片的例外
这是该活动的相关代码:
package com.example.cribbage2;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.os.Bundle;
import java.util.Arrays;
public class PointCalculator extends FragmentActivity implements CardKeyboardFrag.InfoTransfer {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_point_calculator);
//set cardKeyboardFrag
CardKeyboardFrag cardFrag = new CardKeyboardFrag();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.add(R.id.fragment_container, cardFrag);
transaction.addToBackStack(null);
transaction.commit();
//tell fragment how many cards you are requesting
}
public void cardNumSet(int cardNumMin, int cardNumMax){
CardKeyboardFrag cardKeyboardFrag = (CardKeyboardFrag) getSupportFragmentManager().findFragmentById(R.id.fragment_container);
cardKeyboardFrag.cardNumGet(cardNumMin, cardNumMax);
}
public void displayResults(int[] resultsIntArray){
//parse intArray into String
String[] resultsStringArray = new String[4];
int loop = 0;
for (int num: resultsIntArray){
resultsStringArray[loop] = Integer.toString(num);
loop++;
}
//transfer to new fragment
PCResultsFrag resultsFrag = new PCResultsFrag();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, resultsFrag);
transaction.addToBackStack(null);
transaction.commit();
//this is the line where the error occurs
PCResultsFrag pcResultsFrag = (PCResultsFrag) getSupportFragmentManager().findFragmentById(R.id.fragment_container);
pcResultsFrag.getResultsArray(resultsStringArray);
}
好了,' R.id.fragment_container'返回给你一个'CardKeyboardFrag',就像你已经做过的那样(CardKeyboardFrag)getSupportFragmentManager()。findFragmentById(R.id.fragment_container);'。但是在这里你试图把它转换成一个不兼容的'PCResultsFrag'。 – QBrute
那么解决方案是什么?如何将PCResultsFrag放入容器?或从容器中删除CardKeyboardFrag? –
@QBrute ^^^^^^^^^ –