Java 无法获取单选按钮id
我试图在单击按钮时获取单选按钮值,但在此行下方显示红线错误: 我想知道为什么会出现这个错误,因为我无法理解Java 无法获取单选按钮id,java,android,android-radiobutton,Java,Android,Android Radiobutton,我试图在单击按钮时获取单选按钮值,但在此行下方显示红线错误: 我想知道为什么会出现这个错误,因为我无法理解 radioSexButton = (RadioButton)findViewById(selectedId); inconvertible types,cannot cast android.view.view to RadioButton 下面是我的代码: XML代码: <LinearLayout xmlns:android="http://schemas.android.co
radioSexButton = (RadioButton)findViewById(selectedId);
inconvertible types,cannot cast android.view.view to RadioButton
下面是我的代码:
XML代码:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".RadioButton"
android:padding="20dp">
<RadioGroup
android:id="@+id/radioSex"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<RadioButton
android:id="@+id/radioMale"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Male"
android:checked="true" />
<RadioButton
android:id="@+id/radioFemale"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Female" />
</RadioGroup>
<Button
android:id="@+id/btnDisplay"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Display" />
有人请让我知道如何解决这个问题,任何帮助将不胜感激
谢谢将代码更改为下面的代码
private View radioSexButton; //make View
int radioButtonID = radioSexGroup.getCheckedRadioButtonId();
radioSexButton = radioSexGroup.findViewById(radioButtonID);
根据您收到的异常消息,强制转换由
findViewById(int)
返回的视图似乎有问题。尝试以下步骤
findViewById(int)
的返回值。它将根据变量的类型自动为您执行此操作import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton; // this is the important part
import android.widget.RadioGroup;
import android.widget.Toast;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
// activity name changed!
public class RadioButtonActivity extends AppCompatActivity {
private RadioGroup radioSexGroup;
private RadioButton radioSexButton;
private Button btnDisplay;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
radioSexGroup = findViewById(R.id.radioSex);
btnDisplay = findViewById(R.id.btnDisplay);
btnDisplay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int selectedId = radioSexGroup.getCheckedRadioButtonId();
radioSexButton = findViewById(selectedId);
// find the radiobutton by returned id
Toast.makeText(getApplicationContext(),
radioSexButton.getText(), Toast.LENGTH_SHORT).show();
}
});
}
}
您遇到此问题是因为您试图将
findViewById(int)
的返回值强制转换为“RadioButton”,它在您的代码中指的是活动,而不是android.widget.RadioButton
,因为您无法调用getText()
在视图上如果我将RadioExButton更改为View,则在Toast RadioExButton中。getText()显示错误请确保下次在示例代码中包含导入;)我正在添加导入只是更新。没关系,我已经发布了一个答案。问题是关于导入和您的活动名称。在我的post plase中添加了导入查看我的导入是的,我可以确认android.widget.RadioButton
的缺少导入与您的活动名称一起是问题所在
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton; // this is the important part
import android.widget.RadioGroup;
import android.widget.Toast;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
// activity name changed!
public class RadioButtonActivity extends AppCompatActivity {
private RadioGroup radioSexGroup;
private RadioButton radioSexButton;
private Button btnDisplay;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
radioSexGroup = findViewById(R.id.radioSex);
btnDisplay = findViewById(R.id.btnDisplay);
btnDisplay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int selectedId = radioSexGroup.getCheckedRadioButtonId();
radioSexButton = findViewById(selectedId);
// find the radiobutton by returned id
Toast.makeText(getApplicationContext(),
radioSexButton.getText(), Toast.LENGTH_SHORT).show();
}
});
}
}