java.lang.ClassCastException：java.lang.Integer 不能转换为 java.lang.Boolean Shared Preference (RadioButtons)

Question

在应用程序中有两个单选按钮，每个按钮都有自己的值，第一个单选按钮的值为“2”，第二个单选按钮的值为“4”。现在我成功实现了共享首选项，以便通过单击单选按钮保存值。但是缺少一件事，如果我选择单选按钮 1，并且如果我关闭应用程序并再次打开应用程序，那么单选按钮 1 未被选中。我还尝试添加radiobutton.setChecked，但它会崩溃。下面是xml和java代码。

custom_dialog.xml

<ScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="15dp">
    <RadioGroup
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/radioGroup" />
</ScrollView>

method0.xml

<resources>
    <integer-array name="method0">
        <item>2</item>
    </integer-array>
</resources>

method1.xml

<resources>
    <integer-array name="method1">
        <item>4</item>
    </integer-array>
</resources>

CustomDialog.java

public class CustomDialog extends AppCompatDialogFragment {
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder=new AlertDialog.Builder(getActivity());
        LayoutInflater layoutInflater=getActivity().getLayoutInflater();
        final View view=layoutInflater.inflate(R.layout.custom_dialog,null);
        RadioGroup radioGroup=view.findViewById(R.id.radioGroup);
        final int[] num0=getResources().getIntArray(R.array.method0);
        final int[] num1=getResources().getIntArray(R.array.method1);
        RadioButton radioButton0=new RadioButton(getActivity());
        RadioButton radioButton1=new RadioButton(getActivity());
        radioButton0.setText("A");
        radioButton0.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int method=num0[0];
                SharedPreferences sharedPreferences=getActivity().getSharedPreferences("METHOD",Context.MODE_PRIVATE);
                SharedPreferences.Editor editor=sharedPreferences.edit();
                editor.putInt("key", method);
                editor.apply();
            }
        });
        radioButton0.setPadding(0,50,0,50);
        radioButton0.setTextSize(17);
        radioButton0.setTypeface(null, Typeface.BOLD);
        radioButton0.setChecked(Update("key")); //Here this line it is getting crashed
        radioButton1.setText("B");
        radioButton1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int method=num1[0];
                SharedPreferences sharedPreferences=getActivity().getSharedPreferences("METHOD",Context.MODE_PRIVATE);
                SharedPreferences.Editor editor=sharedPreferences.edit();
                editor.putInt("key", method);
                editor.apply();
            }
        });
        radioButton1.setPadding(0,50,0,50);
        radioButton1.setTextSize(17);
        radioButton1.setTypeface(null, Typeface.BOLD);
        radioGroup.addView(radioButton0);
        radioGroup.addView(radioButton1);
        builder.setView(view)
                .setTitle("Select Any Methods")
                .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                    }
                });
        return builder.create();
    }
    private boolean Update(String key){ 
        SharedPreferences sharedPreferences=getActivity().getSharedPreferences("METHOD",Context.MODE_PRIVATE);
        return sharedPreferences.getBoolean(key,false); //Here this line it is getting crashed
    }
}

MainActivity.java

    btnMethod.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            openDialog(); //this will open the dialog along with two radiobuttons
        }
    });
private void openDialog() {
    CustomDialog customDialog=new CustomDialog();
    customDialog.show(getSupportFragmentManager(),"Custom Dialog");
}

Logcat

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.nabil.myapplication, PID: 17062
    java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Boolean
        at android.app.SharedPreferencesImpl.getBoolean(SharedPreferencesImpl.java:326)
        at com.nabil.myapplication.CustomDialog.Update(CustomDialog.java:295)
        at com.nabil.myapplication.CustomDialog.onCreateDialog(CustomDialog.java:69)

Answer 1

我对android代码不太了解，但是，如果我只是通过你的错误，那么它就来了，因为Integer和boolean这两个类之间没有父子关系。

Answer 2

这是因为您在共享首选项中存储了一个整数，然后尝试检索一个布尔值。

我建议像这样存储单选按钮的值：

editor.putBoolean("radioButton0", radioButton0.isChecked());

...

editor.putBoolean("radioButton1", radioButton1.isChecked());

已编辑：

而不是使用

editor.putInt("key", method);

用途：

editor.putBoolean("radioButton0", radioButton0.isChecked());

与

而不是使用

radioButton0.setChecked(Update("key"));

用途：

radioButton0.setChecked(Update("radioButton0"));

这应该像你想要的那样工作。