android - 选择新的微调项时从数组中删除值

Question

我正在创建应用程序。我在其中通过微调器询问用户的血型，当用户选择血型时，我将血型添加到他可以献血的数组列表中。就像他选择血型 O-，我将添加所有血型排列为 O- 都可以向所有人献血。直到当用户错误地选择 O- 然后他选择 A- 时，它的工作正常问题才出现，所以现在我应该如何从 arrayList 中删除以前的组并添加组A-可以献血给谁现在我正在这样做:

    spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                matchedGrpToDonate = spinner.getSelectedItem().toString();
                matchedBloodGroups();
            }
            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });
private void matchedBloodGroups() {
        if (matchedGrpToDonate.equals("A+")) {
            bloodBankCanDonate.add("AB+");
            bloodBankCanDonate.add("A+");
            System.out.println("hash" + bloodBankCanDonate);
        } else if (matchedGrpToDonate.equals("A+")) {
            bloodBankCanDonate.remove("AB+");
            bloodBankCanDonate.remove("A+");
            System.out.println("hash" + bloodBankCanDonate);
        }

        if (matchedGrpToDonate.equals("A-")) {
            bloodBankCanDonate.add("AB+");
            bloodBankCanDonate.add("A+");
            bloodBankCanDonate.add("AB-");
            bloodBankCanDonate.add("A-");
            System.out.println("hash" + bloodBankCanDonate);
        } else if (matchedGrpToDonate.equals("A-")) {
            bloodBankCanDonate.remove("AB+");
            bloodBankCanDonate.remove("A+");
            bloodBankCanDonate.remove("AB-");
            bloodBankCanDonate.remove("A-");
            System.out.println("hash" + bloodBankCanDonate);
        }

        if (matchedGrpToDonate.equals("B+")) {
            bloodBankCanDonate.add("AB+");
            bloodBankCanDonate.add("B+");
            System.out.println("hash" + bloodBankCanDonate);
        } else if (matchedGrpToDonate.equals("B+")) {
            bloodBankCanDonate.remove("AB+");
            bloodBankCanDonate.remove("B+");
            System.out.println("hash" + bloodBankCanDonate);
        }

        if (matchedGrpToDonate.equals("B-")) {
            bloodBankCanDonate.add("AB+");
            bloodBankCanDonate.add("B+");
            bloodBankCanDonate.add("AB-");
            bloodBankCanDonate.add("B-");
            System.out.println("hash" + bloodBankCanDonate);
        } else if (matchedGrpToDonate.equals("B-")) {
            bloodBankCanDonate.remove("AB+");
            bloodBankCanDonate.remove("B+");
            bloodBankCanDonate.remove("AB-");
            bloodBankCanDonate.remove("B-");
            System.out.println("hash" + bloodBankCanDonate);
        }

        if (matchedGrpToDonate.equals("O+")) {
            bloodBankCanDonate.add("AB+");
            bloodBankCanDonate.add("A+");
            bloodBankCanDonate.add("B+");
            bloodBankCanDonate.add("O+");
            System.out.println("hash" + bloodBankCanDonate);

        } else if (matchedGrpToDonate.equals("O+")) {
            bloodBankCanDonate.remove("AB+");
            bloodBankCanDonate.remove("A+");
            bloodBankCanDonate.remove("B+");
            bloodBankCanDonate.remove("O+");
            System.out.println("hash" + bloodBankCanDonate);
        }

        if (matchedGrpToDonate.equals("O-")) {
            bloodBankCanDonate.add("AB+");
            bloodBankCanDonate.add("A+");
            bloodBankCanDonate.add("B+");
            bloodBankCanDonate.add("O+");
            bloodBankCanDonate.add("AB-");
            bloodBankCanDonate.add("A-");
            bloodBankCanDonate.add("B-");
            bloodBankCanDonate.add("O-");
            System.out.println("hash" + bloodBankCanDonate);
        } else if (matchedGrpToDonate.equals("O-")) {
            bloodBankCanDonate.remove("AB+");
            bloodBankCanDonate.remove("A+");
            bloodBankCanDonate.remove("B+");
            bloodBankCanDonate.remove("O+");
            bloodBankCanDonate.remove("AB-");
            bloodBankCanDonate.remove("A-");
            bloodBankCanDonate.remove("B-");
            bloodBankCanDonate.remove("O-");
            System.out.println("hash" + bloodBankCanDonate);
        }
    }

Answer 1

您可以在 if 语句中添加一个检查，如果数组列表不为空，则清除它并像这样添加血型值:

private void matchedBloodGroups() {
        if (matchedGrpToDonate.equals("A+")) {
            if (!bloodBankCanDonate.isEmpty())
                bloodBankCanDonate.clear();
            bloodBankCanDonate.add("AB+");
            bloodBankCanDonate.add("A+");
            System.out.println("hash" + bloodBankCanDonate);
        }
        if (matchedGrpToDonate.equals("A-")) {
            if (!bloodBankCanDonate.isEmpty())
                bloodBankCanDonate.clear();
            bloodBankCanDonate.add("AB+");
            bloodBankCanDonate.add("A+");
            bloodBankCanDonate.add("AB-");
            bloodBankCanDonate.add("A-");
            System.out.println("hash" + bloodBankCanDonate);
        }

您可以对其他血型进行同样的操作，但请记住，此条件仅适用于您选择可以献血的血型。