如何利用onSaveInstanceState和onRestoreInstanceState保存单选、复选框选中状态？

看起来你已经找对了方向——用onSaveInstanceState和onRestoreInstanceState来保存状态，但目前的代码只处理了正确答案的颜色，没保存RadioButton、CheckBox的选中状态，也没留存EditText的输入内容。咱们一步步来修复这个问题：

第一步：声明成员变量存储关键状态 #

先把需要跨生命周期保存的变量改成Activity的成员变量，这样各个生命周期方法都能访问到：

public class Activity1 extends AppCompatActivity {
    // 控件声明
    private Button finishButton;
    private EditText enterName, answer1;
    private RadioButton answer2, answer3, answer5;
    private CheckBox answer41, answer42, answer43, answer44, answer45;
    
    // 新增成员变量存储状态
    private boolean isQuizFinished = false; // 标记是否点击过「完成」按钮
    private String answer1Input;
    private boolean answer2Checked, answer3Checked, answer5Checked;
    private boolean answer41Checked, answer42Checked, answer43Checked, answer44Checked, answer45Checked;
    private boolean isQ1Correct, isQ2Correct, isQ3Correct, isQ4Correct, isQ5Correct;

    // ... 其他代码
}

第二步：完善onSaveInstanceState方法 #

在这个方法里，把所有需要保留的状态存入Bundle：

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    
    // 保存EditText输入内容
    outState.putString("answer1Input", answer1.getText().toString());
    outState.putString("userName", enterName.getText().toString());
    
    // 保存RadioButton选中状态
    outState.putBoolean("answer2Checked", answer2.isChecked());
    outState.putBoolean("answer3Checked", answer3.isChecked());
    outState.putBoolean("answer5Checked", answer5.isChecked());
    
    // 保存CheckBox选中状态
    outState.putBoolean("answer41Checked", answer41.isChecked());
    outState.putBoolean("answer42Checked", answer42.isChecked());
    outState.putBoolean("answer43Checked", answer43.isChecked());
    outState.putBoolean("answer44Checked", answer44.isChecked());
    outState.putBoolean("answer45Checked", answer45.isChecked());
    
    // 保存测验完成状态和题目对错标记
    outState.putBoolean("isQuizFinished", isQuizFinished);
    outState.putBoolean("isQ1Correct", isQ1Correct);
    outState.putBoolean("isQ2Correct", isQ2Correct);
    outState.putBoolean("isQ3Correct", isQ3Correct);
    outState.putBoolean("isQ4Correct", isQ4Correct);
    outState.putBoolean("isQ5Correct", isQ5Correct);
}

第三步：恢复状态并复用颜色设置逻辑 #

我们在onCreate里先判断是否有保存的状态，然后逐一恢复；同时把设置正确答案颜色的逻辑抽成方法，避免重复代码：

1. 新增颜色设置复用方法 #

private void setCorrectAnswerColors() {
    // 设置正确的EditText颜色
    if (isQ1Correct) {
        answer1.setTextColor(0xAA76FF03);
    }
    
    // 设置正确的RadioButton颜色
    if (isQ2Correct) answer2.setTextColor(0xAA76FF03);
    if (isQ3Correct) answer3.setTextColor(0xAA76FF03);
    if (isQ5Correct) answer5.setTextColor(0xAA76FF03);
    
    // 设置正确的CheckBox颜色
    if (isQ4Correct) {
        answer42.setTextColor(0xAA76FF03);
        answer43.setTextColor(0xAA76FF03);
        answer44.setTextColor(0xAA76FF03);
        answer45.setTextColor(0xAA76FF03);
    }
}

2. 在onCreate中恢复状态 #

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.html_new_page);
    
    // 初始化控件（原有代码）
    finishButton = findViewById(R.id.finish_button);
    enterName = findViewById(R.id.enter_name);
    answer1 = findViewById(R.id.answer_1);
    answer2 = findViewById(R.id.answer2);
    answer3 = findViewById(R.id.answer3);
    answer5 = findViewById(R.id.answer5);
    answer41 = findViewById(R.id.answer41);
    answer42 = findViewById(R.id.answer42);
    answer43 = findViewById(R.id.answer43);
    answer44 = findViewById(R.id.answer44);
    answer45 = findViewById(R.id.answer45);
    
    // 恢复保存的状态
    if (savedInstanceState != null) {
        // 恢复EditText内容
        answer1Input = savedInstanceState.getString("answer1Input");
        answer1.setText(answer1Input);
        enterName.setText(savedInstanceState.getString("userName"));
        
        // 恢复RadioButton选中状态
        answer2Checked = savedInstanceState.getBoolean("answer2Checked");
        answer2.setChecked(answer2Checked);
        answer3Checked = savedInstanceState.getBoolean("answer3Checked");
        answer3.setChecked(answer3Checked);
        answer5Checked = savedInstanceState.getBoolean("answer5Checked");
        answer5.setChecked(answer5Checked);
        
        // 恢复CheckBox选中状态
        answer41Checked = savedInstanceState.getBoolean("answer41Checked");
        answer41.setChecked(answer41Checked);
        answer42Checked = savedInstanceState.getBoolean("answer42Checked");
        answer42.setChecked(answer42Checked);
        answer43Checked = savedInstanceState.getBoolean("answer43Checked");
        answer43.setChecked(answer43Checked);
        answer44Checked = savedInstanceState.getBoolean("answer44Checked");
        answer44.setChecked(answer44Checked);
        answer45Checked = savedInstanceState.getBoolean("answer45Checked");
        answer45.setChecked(answer45Checked);
        
        // 恢复测验完成状态和对错标记
        isQuizFinished = savedInstanceState.getBoolean("isQuizFinished");
        isQ1Correct = savedInstanceState.getBoolean("isQ1Correct");
        isQ2Correct = savedInstanceState.getBoolean("isQ2Correct");
        isQ3Correct = savedInstanceState.getBoolean("isQ3Correct");
        isQ4Correct = savedInstanceState.getBoolean("isQ4Correct");
        isQ5Correct = savedInstanceState.getBoolean("isQ5Correct");
        
        // 如果已经完成测验，显示正确答案颜色
        if (isQuizFinished) {
            setCorrectAnswerColors();
        }
    }
    
    // 原有「完成」按钮点击事件（稍作修改）
    finishButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            isQuizFinished = true;
            
            answer1Input = answer1.getText().toString();
            answer2Checked = answer2.isChecked();
            answer3Checked = answer3.isChecked();
            answer41Checked = answer41.isChecked();
            answer42Checked = answer42.isChecked();
            answer43Checked = answer43.isChecked();
            answer44Checked = answer44.isChecked();
            answer45Checked = answer45.isChecked();
            answer5Checked = answer5.isChecked();
            
            // 判断题目对错
            isQ1Correct = answer1Input.equals("Hypertext Markup Language") || answer1Input.equals("HyperText Markup Language");
            isQ2Correct = answer2Checked;
            isQ3Correct = answer3Checked;
            isQ5Correct = answer5Checked;
            isQ4Correct = !answer41Checked && answer42Checked && answer43Checked && answer44Checked && answer45Checked;
            
            // 设置正确答案颜色
            setCorrectAnswerColors();
            
            // 计算得分并跳转（原有代码）
            int correctNumber = (isQ1Correct ? 1 : 0) + (isQ2Correct ? 1 : 0) + (isQ3Correct ? 1 : 0) + (isQ4Correct ? 1 : 0) + (isQ5Correct ? 1 : 0);
            String correct = Integer.toString(correctNumber);
            
            Intent i = new Intent(Activity1.this, ResultActivity.class);
            i.putExtra("outData", enterName.getText().toString());
            i.putExtra("out", correct);
            startActivity(i);
        }
    });
}

可选：补充onRestoreInstanceState方法 #

如果你习惯在onRestoreInstanceState里处理状态恢复，也可以添加这段代码（逻辑和onCreate里的恢复部分一致）：

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    
    answer1Input = savedInstanceState.getString("answer1Input");
    answer1.setText(answer1Input);
    enterName.setText(savedInstanceState.getString("userName"));
    
    answer2Checked = savedInstanceState.getBoolean("answer2Checked");
    answer2.setChecked(answer2Checked);
    answer3Checked = savedInstanceState.getBoolean("answer3Checked");
    answer3.setChecked(answer3Checked);
    answer5Checked = savedInstanceState.getBoolean("answer5Checked");
    answer5.setChecked(answer5Checked);
    
    answer41Checked = savedInstanceState.getBoolean("answer41Checked");
    answer41.setChecked(answer41Checked);
    answer42Checked = savedInstanceState.getBoolean("answer42Checked");
    answer42.setChecked(answer42Checked);
    answer43Checked = savedInstanceState.getBoolean("answer43Checked");
    answer43.setChecked(answer43Checked);
    answer44Checked = savedInstanceState.getBoolean("answer44Checked");
    answer44.setChecked(answer44Checked);
    answer45Checked = savedInstanceState.getBoolean("answer45Checked");
    answer45.setChecked(answer45Checked);
    
    isQuizFinished = savedInstanceState.getBoolean("isQuizFinished");
    isQ1Correct = savedInstanceState.getBoolean("isQ1Correct");
    isQ2Correct = savedInstanceState.getBoolean("isQ2Correct");
    isQ3Correct = savedInstanceState.getBoolean("isQ3Correct");
    isQ4Correct = savedInstanceState.getBoolean("isQ4Correct");
    isQ5Correct = savedInstanceState.getBoolean("isQ5Correct");
    
    if (isQuizFinished) {
        setCorrectAnswerColors();
    }
}

现在测试一下，旋转屏幕后用户的选择会完全保留，且如果已经完成测验，正确答案的绿色也会正常显示啦。

内容的提问来源于stack exchange，提问作者Cansu Yeksan