我正在使用 SwiftUI 的 tabview。我有使用以下方法显示和隐藏 tabview 特定页面的方法
#include <iostream>
#include <vector>
#include <numeric>
#include <iterator>
using std::cout;
void printMatrixArray(std::size_t rowSize, const std::vector<int>& matArray){
std::size_t elementCount = 1;
std::vector<int>::const_iterator it = matArray.cbegin();
for(std::size_t row = 0; row < rowSize; ++row){
std::copy(it, it + elementCount, std::ostream_iterator<int>(cout, "\t"));
cout<< '\n';
it += elementCount;
++elementCount;
}
}
std::vector<int> leftDiagonalBottomMatrix(const std::vector<std::vector<int>>& mat){
std::vector<int> res;
res.reserve(((1 + mat.size()) * mat.size()) / 2);
std::vector<int>::size_type elementCount = 1;
for(const std::vector<int>& row : mat){
for(std::vector<int>::const_iterator it = row.cbegin(), endIt = row.cbegin() + elementCount; endIt != it; ++it){
res.push_back(*it);
}
++elementCount;
}
return res;
}
std::vector<int> multiplyMatrixArrays(const std::vector<int>& mat1Arr, const std::vector<int>& mat2Arr,
std::vector<int>::size_type rowSize){
std::vector<int> auxiliaryArray(rowSize);
auxiliaryArray.front() = 0;
std::iota(auxiliaryArray.begin() + 1, auxiliaryArray.end(), 1);
std::partial_sum(auxiliaryArray.cbegin(), auxiliaryArray.cend(), auxiliaryArray.begin());
std::vector<int> res;
res.reserve(mat1Arr.size());
for(std::vector<int>::size_type row = 0; row < rowSize; ++row){
for(std::vector<int>::size_type col = 0; col <= row; ++col){
int val = 0;
for(std::vector<int>::size_type ele = col, elementCount = row + 1; ele < elementCount; ++ele){
val += mat1Arr[auxiliaryArray[row] + ele] * mat2Arr[auxiliaryArray[ele] + col];
}
res.push_back(val);
}
}
return res;
}
std::vector<int> matrixMultiply(const std::vector<std::vector<int>>& mat1, const std::vector<std::vector<int>>& mat2){
return multiplyMatrixArrays(leftDiagonalBottomMatrix(mat1), leftDiagonalBottomMatrix(mat2), mat1.size());
}
int main(){
std::vector<std::vector<int>> mat1{{1, 0, 0, 0, 0}, {2, 3, 0, 0, 0}, {4, 1, 3, 0, 0}, {1, 9, 0, 2, 0},
{1, 0, 1, 2, 2}};
std::vector<std::vector<int>> mat2{{2, 0, 0, 0, 0}, {1, 1, 0, 0, 0}, {0, 1, 2, 0, 0}, {1, 1, 2, 3, 0},
{2, 0, 0, 1, 2}};
printMatrixArray(mat1.size(), matrixMultiply(mat1, mat2));
}
使用此方法 tabview hidden 工作正常。在隐藏标签页中，当焦点显示文本字段 tabview 时。如何处理这个