如何使用 onSaveInstanceState 和 onRestoreInstanceState 来防止丢失复选框和单选按钮选择

Question

我在保存单选按钮和复选框的复选状态时遇到问题。如何使用 onSaveInstanceState 和 onRestoreInstanceState 保存这些元素的检查状态？

这是一个简单的测验应用程序。单击完成按钮后，将打开一个新分数 sheet，同时正确答案变为 green.but，当方向改变时，用户的选择将丢失。

代码如下：

protected void onSaveInstanceState(Bundle outState)
    {
        super.onSaveInstanceState(outState);

        answer2.setTextColor(0xAA76FF03);
        answer3.setTextColor(0xAA76FF03);
        answer5.setTextColor(0xAA76FF03);
        answer42.setTextColor(0xAA76FF03);
        answer43.setTextColor(0xAA76FF03);
        answer44.setTextColor(0xAA76FF03);
        answer45.setTextColor(0xAA76FF03);
    }
    protected void onRestoreInstanceState(Bundle savedState)
    {
        answer2.setTextColor(0xAA76FF03);
        answer3.setTextColor(0xAA76FF03);
        answer5.setTextColor(0xAA76FF03);
        answer42.setTextColor(0xAA76FF03);
        answer43.setTextColor(0xAA76FF03);
        answer44.setTextColor(0xAA76FF03);
        answer45.setTextColor(0xAA76FF03);

    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.html_new_page);
        finishButton = (Button) findViewById(R.id.finish_button);
        enterName = (EditText) findViewById(R.id.enter_name);
        answer1 = (EditText) findViewById(R.id.answer_1);
        answer2 = (RadioButton)findViewById(R.id.answer2) ;
        answer3 = (RadioButton)findViewById(R.id.answer3);
        answer5 = (RadioButton)findViewById(R.id.answer5);
        answer41 = (CheckBox)findViewById(R.id.answer41);
        answer42 = (CheckBox) findViewById(R.id.answer42);
        answer43 = (CheckBox) findViewById(R.id.answer43);
        answer44 = (CheckBox) findViewById(R.id.answer44);
        answer45 = (CheckBox) findViewById(R.id.answer45);

        finishButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                String checkAnswer1 = answer1.getText().toString();
                c2 = answer2.isChecked();
                c3 = answer3.isChecked();
                checkAnswer41 = answer41.isChecked();
                checkAnswer42 = answer42.isChecked();
                checkAnswer43 = answer43.isChecked();
                checkAnswer44 = answer44.isChecked();
                checkAnswer45 = answer45.isChecked();
                c5 = answer5.isChecked();

                if ( checkAnswer1.equals("Hypertext Markup Language") || checkAnswer1.equals("HyperText Markup Language")) {
                    c1 = true;
                    answer1.setTextColor(0xAA76FF03);
                }
                else {
                    c1 = false;
                }

                if (checkAnswer41 == false && checkAnswer42 == true && checkAnswer43 == true && checkAnswer44 == true && checkAnswer45 == true){
                    c4 = true;
                }
                else {
                    c4 = false;
                }

                int q1 = (c1) ? 1 : 0;
                int q2 = (c2) ? 1 : 0;
                int q3 = (c3) ? 1 : 0;
                int q4 = (c4) ? 1 : 0;
                int q5 = (c5) ? 1 : 0;

                int correctNumber = q1 + q2 + q3 + q4 + q5;
                correct = Integer.toString(correctNumber);

                Intent i = new Intent();
                i.setClass(Activity1.this, ResultActivity.class);
                i.putExtra("outData", enterName.getText().toString());
                i.putExtra("out", correct);

                startActivity(i);
            }
        });
    };
}

Answer 1

这是例子。

static final String STATE_USER = "user";
private String mUser;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Check whether we're recreating a previously destroyed instance
if (savedInstanceState != null) {
    // Restore value of members from saved state
    mUser = savedInstanceState.getString(STATE_USER);
} else {
    // Probably initialize members with default values for a new instance
    mUser = "NewUser";
}
}

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
savedInstanceState.putString(STATE_USER, mUser);
// Always call the superclass so it can save the view hierarchy state
super.onSaveInstanceState(savedInstanceState);
}

和Ref

的官方文档

Answer 2

使用类似这样的东西：（调整到你自己的代码）

public class YourActivity extends AppCompatActivity {

    private static final String CHECKBOX_CHECKED_KEY = "is_checkbox_checked";

    private CheckBox myCheckBox;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        ...

        if (savedInstanceState != null) {

            myCheckBox.setChecked(savedInstanceState.getBoolean(CHECKBOX_CHECKED_KEY));
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {

        super.onSaveInstanceState(outState)
        outState.putBoolean(CHECKBOX_CHECKED_KEY, myCheckBox.isChecked());
    }
}

您需要为要保存的每个 CheckBoxe 状态定义不同的键。

如何使用 onSaveInstanceState 和 onRestoreInstanceState 来防止丢失复选框和单选按钮选择

How to use onSaveInstanceState and onRestoreInstanceState to prevent losing checkbox and radiobutton selections

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