Question

我已经尝试了几天来正确实现onSaveInstanceState()方法，但直到现在还没有成功。

我做错了什么？我的代码没有返回错误，但是没有保存复选框的状态？

是否可以实施onSaveInstanceState()方法？

如果我使用SharedPreferences会不会更好？

我想要的是不要在旋转屏幕时丢失复选框选项。如果有人能够纠正我正在做的事情，我将不胜感激！

这就是我所拥有的：

MainActivity.java：

package com.example.alex.savepreferencescheckbox;

import android.annotation.SuppressLint;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.CheckBox;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    AlertDialog dialog;
    CheckBox cbAllDay, cbBefore12, cbBetween1216, cbBetween1620, ccbAfter20;
    Boolean myBoolean1, myBoolean2, myBoolean3, myBoolean4, myBoolean5;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    public void alertDialog(View view) {

        if (dialog == null) {

            AlertDialog.Builder builder;
            builder = new AlertDialog.Builder(this);
            LayoutInflater inflater = this.getLayoutInflater();
            @SuppressLint("InflateParams") View checkBoxView = inflater.inflate(R.layout.markers_filtering, null);
            builder.setView(checkBoxView);
            cbAllDay = (CheckBox) checkBoxView.findViewById(R.id.checkBox1);
            cbBefore12 = (CheckBox) checkBoxView.findViewById(R.id.checkBox2);
            cbBetween1216 = (CheckBox) checkBoxView.findViewById(R.id.checkBox3);
            cbBetween1620 = (CheckBox) checkBoxView.findViewById(R.id.checkBox4);
            ccbAfter20 = (CheckBox) checkBoxView.findViewById(R.id.checkBox5);


            dialog = builder.create();

        }
        dialog.show();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putBoolean("CheckBox1", cbAllDay.isChecked());
        outState.putBoolean("CheckBox2", cbBefore12.isChecked());
        outState.putBoolean("CheckBox3", cbBetween1216.isChecked());
        outState.putBoolean("CheckBox4", cbBetween1620.isChecked());
        outState.putBoolean("CheckBox5", ccbAfter20.isChecked());

    }


    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        myBoolean1 = savedInstanceState.getBoolean("CheckBox1");
        myBoolean2 = savedInstanceState.getBoolean("CheckBox2");
        myBoolean3 = savedInstanceState.getBoolean("CheckBox3");
        myBoolean4 = savedInstanceState.getBoolean("CheckBox4");
        myBoolean5 = savedInstanceState.getBoolean("CheckBox5");
    }

    public void applyFilter(View view) {

        dialog.dismiss();

        if (cbAllDay.isChecked()){
            Toast.makeText(this, "The first box was checked", Toast.LENGTH_SHORT).show();

        } else if (cbBefore12.isChecked()){
            Toast.makeText(this, "The second box was checked", Toast.LENGTH_SHORT).show();

        } else if (cbBetween1216.isChecked()){
            Toast.makeText(this, "The third box was checked", Toast.LENGTH_SHORT).show();

        } else if (cbBetween1620.isChecked()){
            Toast.makeText(this, "The forth box was checked", Toast.LENGTH_SHORT).show();

        } else if (ccbAfter20.isChecked()){
            Toast.makeText(this, "The fifth box was checked", Toast.LENGTH_SHORT).show();

        }
    }

    public void doNothing(View view) {

        dialog.dismiss();
    }
}

activity_main.xml中：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.alex.savepreferencescheckbox.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:id="@+id/textView" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Button"
        android:id="@+id/button"
        android:layout_marginTop="71dp"
        android:layout_below="@+id/textView"
        android:layout_alignParentStart="true"
        android:onClick="alertDialog"/>
</RelativeLayout>

markers_filtering.xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Choose Your Hour!"
        android:textSize="25sp"
        android:layout_marginTop="20dp"
        android:layout_marginBottom="10dp"
        android:layout_gravity="center"
        android:id="@+id/title_hour_selection"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <CheckBox
        android:id="@+id/checkBox1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/title_hour_selection"
        android:layout_marginLeft="30dp"
        android:layout_marginStart="30dp"
        android:text="All day long" />

    <CheckBox
        android:id="@+id/checkBox2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="30dp"
        android:layout_marginStart="30dp"
        android:text="Before 12 P.M."
        android:layout_below="@+id/checkBox1"/>

    <CheckBox
        android:id="@+id/checkBox3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/checkBox2"
        android:layout_marginLeft="30dp"
        android:layout_marginStart="30dp"
        android:text="Between 12.00 P.M. - 16.00 P.M." />

    <CheckBox
        android:id="@+id/checkBox4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/checkBox3"
        android:layout_marginLeft="30dp"
        android:layout_marginStart="30dp"
        android:text="Between 16.00 P.M. - 20.00 P.M." />

    <CheckBox
        android:id="@+id/checkBox5"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="30dp"
        android:layout_marginStart="30dp"
        android:layout_below="@+id/checkBox4"
        android:text="After 20.00 P.M."
        android:layout_marginBottom="10dp"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="OK"
        android:layout_marginLeft="30dp"
        android:layout_marginStart="30dp"
        android:layout_marginBottom="30dp"
        android:layout_below="@+id/checkBox5"
        android:id="@+id/okButton"
        android:onClick="applyFilter"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Cancel"
        android:id="@+id/cancelButton"
        android:layout_below="@+id/checkBox5"
        android:layout_alignRight="@+id/checkBox5"
        android:layout_alignEnd="@+id/checkBox5"
        android:layout_marginRight="30dp"
        android:layout_marginEnd="30dp"
        android:layout_marginBottom="30dp"
        android:onClick="doNothing"/>


</RelativeLayout>

Answer 1

新编辑：

我做了一个与你类似的项目并进行了测试。您的代码看起来不错，但只有您忘记的是使用alertDialog()方法提供的保存值在onRestoreInstanceState()方法中设置复选框。

以下是 MainActivity.java的完整代码：

package com.example.alex.savepreferencescheckbox;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.CheckBox;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    AlertDialog dialog;
    CheckBox cbAllDay, cbBefore12, cbBetween1216, cbBetween1620, ccbAfter20;
    Boolean myBoolean1, myBoolean2, myBoolean3, myBoolean4, myBoolean5;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void alertDialog(View view) {

        if (dialog == null) {

            AlertDialog.Builder builder;
            builder = new AlertDialog.Builder(this);
            LayoutInflater inflater = this.getLayoutInflater();
            @SuppressLint("InflateParams") View checkBoxView = inflater.inflate(R.layout.markers_filtering, null);
            builder.setView(checkBoxView);

            cbAllDay = (CheckBox) checkBoxView.findViewById(R.id.checkBox1);
            if (myBoolean1 != null) {
                cbAllDay.setChecked(myBoolean1);
            }
            cbBefore12 = (CheckBox) checkBoxView.findViewById(R.id.checkBox2);
            if (myBoolean2 != null) {
                cbBefore12.setChecked(myBoolean2);
            }

            cbBetween1216 = (CheckBox) checkBoxView.findViewById(R.id.checkBox3);
            if (myBoolean3 != null) {
                cbBetween1216.setChecked(myBoolean3);
            }

            cbBetween1620 = (CheckBox) checkBoxView.findViewById(R.id.checkBox4);
            if (myBoolean4 != null) {
                cbBetween1620.setChecked(myBoolean4);
            }

            ccbAfter20 = (CheckBox) checkBoxView.findViewById(R.id.checkBox5);
            if (myBoolean5 != null) {
                ccbAfter20.setChecked(myBoolean5);
            }

            dialog = builder.create();
        }
        dialog.show();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putBoolean("CheckBox1", cbAllDay.isChecked());
        outState.putBoolean("CheckBox2", cbBefore12.isChecked());
        outState.putBoolean("CheckBox3", cbBetween1216.isChecked());
        outState.putBoolean("CheckBox4", cbBetween1620.isChecked());
        outState.putBoolean("CheckBox5", ccbAfter20.isChecked());
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        myBoolean1 = savedInstanceState.getBoolean("CheckBox1");
        myBoolean2 = savedInstanceState.getBoolean("CheckBox2");
        myBoolean3 = savedInstanceState.getBoolean("CheckBox3");
        myBoolean4 = savedInstanceState.getBoolean("CheckBox4");
        myBoolean5 = savedInstanceState.getBoolean("CheckBox5");
    }

    public void applyFilter(View view) {

        dialog.dismiss();

        if (cbAllDay.isChecked()) {
            Toast.makeText(this, "The first box was checked", Toast.LENGTH_SHORT).show();
        } else if (cbBefore12.isChecked()) {
            Toast.makeText(this, "The second box was checked", Toast.LENGTH_SHORT).show();
        } else if (cbBetween1216.isChecked()) {
            Toast.makeText(this, "The third box was checked", Toast.LENGTH_SHORT).show();
        } else if (cbBetween1620.isChecked()) {
            Toast.makeText(this, "The forth box was checked", Toast.LENGTH_SHORT).show();
        } else if (ccbAfter20.isChecked()) {
            Toast.makeText(this, "The fifth box was checked", Toast.LENGTH_SHORT).show();
        }
    }

    public void doNothing(View view) {

        dialog.dismiss();
    }
}

以下是模拟器的截图（Galaxy Nexus API 23，它也适用于API 16，我已经测试过了）：

肖像模式：

横向模式：

Answer 2

在manifest.xml中添加此行，其中u声明活动，阻止在屏幕旋转时重新创建视图

机器人：configChanges = “keyboardHidden |取向”

Answer 3

在您的代码中查看您正在检索复选框状态是什么，但除了将变量设置为它之外，您没有对其执行任何操作：

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    myBoolean1 = savedInstanceState.getBoolean("CheckBox1");
    myBoolean2 = savedInstanceState.getBoolean("CheckBox2");
    myBoolean3 = savedInstanceState.getBoolean("CheckBox3");
    myBoolean4 = savedInstanceState.getBoolean("CheckBox4");
    myBoolean5 = savedInstanceState.getBoolean("CheckBox5");
}

您需要做的是将复选框设置为每个布尔值的内容：

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    myBoolean1 = savedInstanceState.getBoolean("CheckBox1");
    cbAllDay.setChecked(myBoolean1);
    // ...Continue with implementation here.
}

多个CheckBox的onSaveInstanceState或SharedPreferences？

3 个答案: