FlutterListView在錯誤的索引或元素處自動更新

我正在嘗試制作一個串列視圖，顯示對某個數字的添加。在圖中，我正在嘗試為 ListView 中的 16 個步驟生成一個加法表。它在加載時看起來很好，但在滾動頂部和底部元素后會自動更新。這個問題只有在基本控制ListView中item個數的變數tableSize的值超過15的時候才明顯，這個問題怎么解決？？

// tableSize = 16 && tCount = 10

這是代碼

return ListView.builder(
  key: UniqueKey(),
  padding: EdgeInsets.symmetric(horizontal: 5),
  itemCount: DataFile.tableSize,
  scrollDirection: Axis.vertical,
  itemBuilder: (context, index) {
    tCount = tCount   1;

    String title;

    print(" Tcount = ${tCount}");

    if (sign == DataFile.divisionSign) {
      double ans = tableNo / tCount;
      title = tableNo.toString()  
          space  
          sign  
          space  
          tCount.toString()  
          space  
          equal  
          space  
          f.format(ans);
    } else {
      int ans;
      if (sign == DataFile.additionSign) {
        ans = tableNo   tCount;
      } else if (sign == DataFile.subtractionSign) {
        ans = tableNo - tCount;
      } else {
        ans = tableNo * tCount;
      }

      title = tableNo.toString()  
          space  
          space  
          sign  
          space  
          space  
          tCount.toString()  
          space  
          space  
          equal  
          space  
          space  
          int.parse(ans.toString()).toString();
      print(title);
    }

    return InkWell(
      child: Container(
        height: cellHeight,
        margin: EdgeInsets.symmetric(
            vertical: ConstantData.getScreenPercentSize(context, 2.3)),
        child: Center(
          child: ConstantWidget.getTextWidget(
              title,
              ConstantData.textColors!,
              ConstantData.getPercentSize(cellHeight, 98),
              FontWeight.w500,
              TextAlign.center),
        ),
      ),
      onTap: () {},
    );
  },
);

uj5u.com熱心網友回復：

tCount需要更改，它是狀態變數中的可變資料。

使用此代碼：

return ListView.builder(
  key: UniqueKey(),
  padding: EdgeInsets.symmetric(horizontal: 5),
  itemCount: DataFile.tableSize,
  scrollDirection: Axis.vertical,
  itemBuilder: (context, index) {

tCount = index   1; //change here 

String title;

print(" Tcount = ${tCount}");

if (sign == DataFile.divisionSign) {
  double ans = tableNo / tCount;
  title = tableNo.toString()  
      space  
      sign  
      space  
      tCount.toString()  
      space  
      equal  
      space  
      f.format(ans);
} else {
  int ans;
  if (sign == DataFile.additionSign) {
    ans = tableNo   tCount;
  } else if (sign == DataFile.subtractionSign) {
    ans = tableNo - tCount;
  } else {
    ans = tableNo * tCount;
  }

  title = tableNo.toString()  
      space  
      space  
      sign  
      space  
      space  
      tCount.toString()  
      space  
      space  
      equal  
      space  
      space  
      int.parse(ans.toString()).toString();
  print(title);
}

return InkWell(
  child: Container(
    height: cellHeight,
    margin: EdgeInsets.symmetric(
        vertical: ConstantData.getScreenPercentSize(context, 2.3)),
    child: Center(
      child: ConstantWidget.getTextWidget(
          title,
          ConstantData.textColors!,
          ConstantData.getPercentSize(cellHeight, 98),
          FontWeight.w500,
          TextAlign.center),
    ),
  ),
  onTap: () {},
);
},
);

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