Question

我是Android开发的初学者。我只想寻求有关我遇到的问题的帮助。问题如下图所示。应用程序显示错误的Toast文本，其中预期的Toast消息是：
Dog: True Cat: False Cow: False
但实际的Toast消息是：
Dog: True Cat: True Cow: False

Image

以下是我的MainActivity Code：

package com.example.johnsethsalazar.checkbox;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private CheckBox c1, c2, c3; // Declaring Checkbox Variables.
    private Button select;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        addListenerOnButton();
        AddListenerToCheckBox1();
    }

    public void addListenerOnButton()
    {
        c1 = (CheckBox) findViewById(R.id.checkBox);
        c2 = (CheckBox) findViewById(R.id.checkBox2);
        c3 = (CheckBox) findViewById(R.id.checkBox3);
        select = (Button) findViewById(R.id.button);

        select.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View view)
            {
                StringBuffer result = new StringBuffer();


                result.append("Dog : ").append(c1.isChecked());//Gives True if Check and False if Not.
                result.append("Cat : ").append(c2.isChecked());
                result.append("Cow : ").append(c3.isChecked());

                Toast.makeText(MainActivity.this, result.toString(), Toast.LENGTH_LONG).show();

            }
        });
    }

    public void AddListenerToCheckBox1()
    {
        c2 = (CheckBox) findViewById(R.id.checkBox);
        c2.setOnClickListener(new View.OnClickListener()//Shows Toast("Dog is Selected") when Checkbox is Clicked.
        {
            @Override
            public void onClick(View view)
            {
                if (((CheckBox) view).isChecked())
                {
                    Toast.makeText(MainActivity.this, "Dog is Selected.", Toast.LENGTH_LONG).show();
                }
            }
        });
    }
}

Answer 1

这是因为你先做

    c1 = (CheckBox) findViewById(R.id.checkBox);
    c2 = (CheckBox) findViewById(R.id.checkBox2);
    c3 = (CheckBox) findViewById(R.id.checkBox3);

你的addListenerOnButton（）中的

是正确的，但是你调用的是AddListenerToCheckBox1（）

c2 = (CheckBox) findViewById(R.id.checkBox);

用狗复选框覆盖c2的值。

我建议您将复选框命名为更人性化的名称，这样就不会让它们混淆。

命名约定会建议checkBoxDog，checkBoxCat，ect

Answer 2

固定解决方案：

package com.example.johnsethsalazar.checkbox;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private CheckBox checkBoxDog, checkBoxCat, checkBoxCow;
    private Button select;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViews();
        addListenerOnButton();
        AddListenerToCheckBox1();
    }

    public void findViews() {
        checkBoxDog = (CheckBox) findViewById(R.id.checkBox);
        checkBoxCat = (CheckBox) findViewById(R.id.checkBox2);
        checkBoxCow = (CheckBox) findViewById(R.id.checkBox3);
        select = (Button) findViewById(R.id.button);
    }

    public void addListenerOnButton() {
        select.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                printState();
            }
        });
    }

    public void printState() {
        StringBuilder result = new StringBuilder();
        result.append("Dog : ").append(checkBoxDog.isChecked());//Gives True if Check and False if Not.
        result.append("Cat : ").append(checkBoxCat.isChecked());
        result.append("Cow : ").append(checkBoxCow.isChecked());
        Toast.makeText(MainActivity.this, result.toString(), Toast.LENGTH_LONG).show();
    }

    public void AddListenerToCheckBox1() {
        checkBoxDog.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isChecked) {
                    Toast.makeText(MainActivity.this, "Dog is Selected.", Toast.LENGTH_LONG).show();   
                }
            }
        });
    }
}

CheckBox.isChecked（）没有返回预期值

2 个答案: