CheckBox.isChecked() 不返回预期值

Question

我是Android开发的初学者。 我只是想就我遇到的问题寻求帮助。 下图显示了该问题。 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

图像

以下是我的主要活动代码：

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

这是因为你首先这样做

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

在你的addListenerOnButton((中是正确的，但是你调用AddListenerToCheckBox1((

这样做

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

用狗复选框覆盖 c2 的值。

我建议将复选框命名为更人性化的名称，以免将它们混淆。

命名约定会建议checkBoxDog，checkBoxCat等

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();   
}
}
});
}
}