如何限制複選框選擇

Question

我正在做一個簡單的測驗應用程序與5個問題。有2個正確的答案和6個複選框可供選擇。我如何做到這一點，以便當選中2個複選框時（對於每個問題），應用程序會阻止用戶再次選擇並顯示Toast消息，指出您無法爲每個問題選中2個以上的複選框？

這是我的代碼（Java，Android Studio中）：

package com.example.android.architecturequizapp; 

import android.content.Context; 
import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.view.View; 
import android.widget.CheckBox; 
import android.widget.EditText; 
import android.widget.RadioButton; 
import android.widget.TextView; 
import android.widget.Toast; 

public class MainActivity extends AppCompatActivity { 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
} 

//method called when Submit&Grade button is clicked 
public void submitAnswers(View view) { 

    //EditText name 
    EditText nameTypeTextBox = (EditText) findViewById(R.id.name_edit_text); 
    String typeName = nameTypeTextBox.getText().toString(); 

    //Question 1: Name Question: Eiffel Tower 
    RadioButton q1Name = (RadioButton) findViewById(R.id.q1_eiffel_tower_radio_button); 
    boolean hasQ1NameCorrect = q1Name.isChecked(); 

    //Question 1: Location Question: Paris 
    CheckBox q1Location1 = (CheckBox) findViewById(R.id.q1_paris_checkbox); 
    boolean hasQ1Location1Correct = q1Location1.isChecked(); 

    //Question 1: Location Question: France 
    CheckBox q1Location2 = (CheckBox) findViewById(R.id.q1_france_checkbox); 
    boolean hasQ1Location2Correct = q1Location2.isChecked(); 

    //Question 2: Name Question: Colosseum 
    RadioButton q2Name = (RadioButton) findViewById(R.id.q2_colosseum_radio_button); 
    boolean hasQ2NameCorrect = q2Name.isChecked(); 

    //Question 2: Location Question: Rome 
    CheckBox q2Location1 = (CheckBox) findViewById(R.id.q2_rome_checkbox); 
    boolean hasQ2Location1Correct = q2Location1.isChecked(); 

    //Question 2: Location Question: Italy 
    CheckBox q2Location2 = (CheckBox) findViewById(R.id.q2_italy_checkbox); 
    boolean hasQ2Location2Correct = q2Location2.isChecked(); 

    //Question 3: Name Question: Tower of Pisa 
    RadioButton q3Name = (RadioButton) findViewById(R.id.q3_tower_of_pisa_radio_button); 
    boolean hasQ3NameCorrect = q3Name.isChecked(); 

    //Question 3: Location Question: Pisa 
    CheckBox q3Location1 = (CheckBox) findViewById(R.id.q3_pisa_checkbox); 
    boolean hasQ3Location1Correct = q3Location1.isChecked(); 

    //Question 3: Location Question: Italy 
    CheckBox q3Location2 = (CheckBox) findViewById(R.id.q3_italy_checkbox); 
    boolean hasQ3Location2Correct = q3Location2.isChecked(); 

    //Question 4: Name Question: Casa Batllo 
    RadioButton q4Name = (RadioButton) findViewById(R.id.q4_casa_batllo_radio_button); 
    boolean hasQ4NameCorrect = q4Name.isChecked(); 

    //Question 4: Location Question: Barcelona 
    CheckBox q4Location1 = (CheckBox) findViewById(R.id.q4_barcelona_checkbox); 
    boolean hasQ4Location1Correct = q4Location1.isChecked(); 

    //Question 4: Location Question: Spain 
    CheckBox q4Location2 = (CheckBox) findViewById(R.id.q4_spain_checkbox); 
    boolean hasQ4Location2Correct = q4Location2.isChecked(); 

    //Question 5: Name Question: Eiffel Tower 
    RadioButton q5Name = (RadioButton) findViewById(R.id.q5_opera_house_radio_button); 
    boolean hasQ5NameCorrect = q5Name.isChecked(); 

    //Question 5: Location Question: Sydney 
    CheckBox q5Location1 = (CheckBox) findViewById(R.id.q5_sydney_checkbox); 
    boolean hasQ5Location1Correct = q5Location1.isChecked(); 

    //Question 5: Location Question: Australia 
    CheckBox q5Location2 = (CheckBox) findViewById(R.id.q5_australia_checkbox); 
    boolean hasQ5Location2Correct = q5Location2.isChecked(); 

    int questionsCorrect = calculateRightAnswers(hasQ1NameCorrect, hasQ1Location1Correct, hasQ1Location2Correct, hasQ2NameCorrect, hasQ2Location1Correct, hasQ2Location2Correct, hasQ3NameCorrect, hasQ3Location1Correct, hasQ3Location2Correct, hasQ4NameCorrect, hasQ4Location1Correct, hasQ4Location2Correct, hasQ5NameCorrect, hasQ5Location1Correct, hasQ5Location2Correct); 

    //toast message for questions correct/score 
    //less than 5 = poor results 
    if (questionsCorrect <= 5) { 
     Context context = getApplicationContext(); 
     CharSequence text = "Poor results! You scored " + questionsCorrect + "/15!"; 
     int duration = Toast.LENGTH_SHORT; 

     Toast toast = Toast.makeText(context, text, duration); 
     toast.show(); 
    } else if (questionsCorrect <= 10) { 
     Context context = getApplicationContext(); 
     CharSequence text = "Average results! You scored " + questionsCorrect + "/15!"; 
     int duration = Toast.LENGTH_SHORT; 

     Toast toast = Toast.makeText(context, text, duration); 
     toast.show(); 
    } else if (questionsCorrect <= 14) { 
     Context context = getApplicationContext(); 
     CharSequence text = "Good results! You scored " + questionsCorrect + "/15!"; 
     int duration = Toast.LENGTH_SHORT; 

     Toast toast = Toast.makeText(context, text, duration); 
     toast.show(); 
    } else { 
     Context context = getApplicationContext(); 
     CharSequence text = "Excellent! You scored " + questionsCorrect + "/15!"; 
     int duration = Toast.LENGTH_SHORT; 

     Toast toast = Toast.makeText(context, text, duration); 
     toast.show(); 
    } 

    //TextView message on bottom 
    endQuiz(typeName); 

} 

//calculate total points scored on quiz 
private int calculateRightAnswers(boolean q1Name, boolean q1Location1, boolean q1Location2, boolean q2Name, boolean q2Location1, boolean q2Location2, boolean q3Name, boolean q3Location1, boolean q3Location2, boolean q4Name, boolean q4Location1, boolean q4Location2, boolean q5Name, boolean q5Location1, boolean q5Location2) { 
    //score before taking quiz 
    int pointsScored = 0; 

    //1 part of Q1 is correct = + 1 point 
    if (q1Name) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q1 is correct = + 1 point 
    if (q1Location1) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q1 is correct = + 1 point 
    if (q1Location2) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q2 is correct = + 1 point 
    if (q2Name) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q2 is correct = + 1 point 
    if (q2Location1) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q2 is correct = + 1 point 
    if (q2Location2) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q3 is correct = + 1 point 
    if (q3Name) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q3 is correct = + 1 point 
    if (q3Location1) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q3 is correct = + 1 point 
    if (q3Location2) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q4 is correct = + 1 point 
    if (q4Name) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q4 is correct = + 1 point 
    if (q4Location1) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q4 is correct = + 1 point 
    if (q4Location2) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q5 is correct = + 1 point 
    if (q5Name) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q5 is correct = + 1 point 
    if (q5Location1) { 
     pointsScored = pointsScored + 1; 
    } 

    //1 part of Q5 is correct = + 1 point 
    if (q5Location2) { 
     pointsScored = pointsScored + 1; 
    } 

    return pointsScored; 
} 

private String endQuiz(String nameTyped) { 
    TextView endingMessageTextView = (TextView) findViewById(R.id.ending_message_text_view); 
    String endQuizMessage = "Thank you " + nameTyped + " for completing the quiz!"; 
    endQuizMessage += "\nHope you enjoyed it!"; 
    endingMessageTextView.setText(endQuizMessage); 
    return endQuizMessage; 
} 

我搜索互聯網尋求幫助，但無法找到任何東西。誰能幫幫我嗎？謝謝。

Answer 1

您可以按照here的說明使用onTouchListener。

checkbox.setOnTouchListener(new OnTouchListener() { 
    @Override 
    public boolean onTouch(View v, MotionEvent event) { 
     if(event.getAction() == MotionEvent.ACTION_UP){ 
      // check if there are already two checkboxes selected 
      // you can use checkbox.isChecked() and a loop for that 
      Toast.makeText(getApplicationContext(), "Only two checkboxes allowed", Toast.LENGTH_SHORT).show(); 
      return true; //this will prevent checkbox from changing state 
     } 
     return false; // this is default and lets event propagate 
    } 
}); 

另一種選擇可能被禁用所有選中的複選框，當第二個複選框被設置，並再次讓他們，當一個人處於未選中狀態。