切换夜间模式的工具类
注意：其中MODE要自己定义一个常量,mMode要在application中创建

/*

• 使用这个类需要把style设置成日夜间的样式:Theme.AppCompat.DayNight.NoActionBar
  */
  public class UIModeUtil {

  /**

  • 夜间模式切换
    */
    public static void changeModeUI(AppCompatActivity activity){
    int currentNightMode = activity.getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK;

    if(currentNightMode == Configuration.UI_MODE_NIGHT_NO){
    //日间模式,切成夜间模式
    activity.getDelegate().setLocalNightMode(AppCompatDelegate.MODE_NIGHT_YES);
    SpUtil.setParam(Constants.MODE,AppCompatDelegate.MODE_NIGHT_YES);
    BaseApp.mMode = AppCompatDelegate.MODE_NIGHT_YES;
    }else{
    activity.getDelegate().setLocalNightMode(AppCompatDelegate.MODE_NIGHT_NO);
    SpUtil.setParam(Constants.MODE,AppCompatDelegate.MODE_NIGHT_NO);
    BaseApp.mMode = AppCompatDelegate.MODE_NIGHT_NO;
    }
    }

  /**

  • 设置当前的模式
  • @param activity
    */
    public static void setActModeFromSp(AppCompatActivity activity){
    int mode = (int) SpUtil.getParam(Constants.MODE, AppCompatDelegate.MODE_NIGHT_NO);
    activity.getDelegate().setLocalNightMode(mode);
    }

  /**

  • 设置当前的模式
  • @param activity
    */
    public static void setActModeUseMode(AppCompatActivity activity,int mode){
    activity.getDelegate().setLocalNightMode(mode);
    }

  public static void setAppMode(int mode){
  AppCompatDelegate.setDefaultNightMode(mode);
  }
  }

SP工具类

public class SpUtil {
/**
* 保存在手机里面的文件名
*/
private static final String FILE_NAME = "share_date";

/**
 * 保存数据的方法，我们需要拿到保存数据的具体类型，然后根据类型调用不同的保存方法
 * @param key
 * @param object 
 */
public static void setParam( String key, Object object){
    
    String type = object.getClass().getSimpleName();
    SharedPreferences sp = BaseApp.getInstance().getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = sp.edit();
    
    if("String".equals(type)){
        editor.putString(key, (String)object);
    }
    else if("Integer".equals(type)){
        editor.putInt(key, (Integer)object);
    }
    else if("Boolean".equals(type)){
        editor.putBoolean(key, (Boolean)object);
    }
    else if("Float".equals(type)){
        editor.putFloat(key, (Float)object);
    }
    else if("Long".equals(type)){
        editor.putLong(key, (Long)object);
    }
    
    editor.commit();
}


/**
 * 得到保存数据的方法，我们根据默认值得到保存的数据的具体类型，然后调用相对于的方法获取值
 * @param key
 * @param defaultObject
 * @return
 */
public static Object getParam(String key, Object defaultObject){
    String type = defaultObject.getClass().getSimpleName();
    SharedPreferences sp = BaseApp.getInstance().getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
    
    if("String".equals(type)){
        return sp.getString(key, (String)defaultObject);
    }
    else if("Integer".equals(type)){
        return sp.getInt(key, (Integer)defaultObject);
    }
    else if("Boolean".equals(type)){
        return sp.getBoolean(key, (Boolean)defaultObject);
    }
    else if("Float".equals(type)){
        return sp.getFloat(key, (Float)defaultObject);
    }
    else if("Long".equals(type)){
        return sp.getLong(key, (Long)defaultObject);
    }
    
    return null;
}

}

在fragment中实现

@Override
protected void initView() {
    super.initView();
    if (BaseApplication.mMode == AppCompatDelegate.MODE_NIGHT_NO) {
        cbNight.setChecked(false);
    } else {
        cbNight.setChecked(true);
    }
}

@Override
protected void initListener() {
    super.initListener();
    cbNight.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
            //判断是否是用户操作
            if (compoundButton.isPressed()) {
                UIModeUtil.changeModeUI((MainActivity) getActivity());
                //保存当前fragment的位置
                SharedPreferencesUtil.setParam(mContext, Constants.FRAGMENT_POSITION, FragmentType.TYPE_SETTINGS);
            }
        }
    });
}

4.在application中初始化
public class BaseApp extends Application{

private static BaseApp baseApp;
public static int mMode= AppCompatDelegate.MODE_NIGHT_NO;

@Override
public void onCreate() {
    super.onCreate();
    baseApp=this;
    dayOrNight();

}

private void dayOrNight() {
    mMode = (int) SpUtil.getParam(Constants.MODE, AppCompatDelegate.MODE_NIGHT_NO);
    UIModeUtil.setAppMode(mMode);
}

public static BaseApp getInstance(){
    return baseApp;
}

}

5.在activity中默认碎片是根据保存的fragment的位置
private void addZhiFragment() {

  int pos = (int) SpUtil.getParam(Constants.NIGHT_CURRENT_FRAG_POS, 1);

  FragmentTransaction transaction = manager.beginTransaction();
  transaction.add(R.id.frame, list.get(0));
  transaction.commit();

}

6.应用退出后保存主页面
@Override
public boolean onTouchEvent(MotionEvent event) {
SpUtil.setParam(Constants.NIGHT_CURRENT_FRAG_POS, MainActivity.TYPE_ZHIHU);
return super.onTouchEvent(event);
}

7.将主题更跟改成切换模式
<style name="AppTheme" parent="Theme.AppCompat.DayNight.NoActionBar">

<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>

8.重新定义一个color文件,将之前的白的变成黑色,黑色变成白的,而且把每一个fragment都加一个背景颜色,不能是透明.