Android NumberPickerPreference-未加载默认值

我想用一个数字比克偏好

基本上，代码按预期工作。将打开一个带有数字图标的对话框。可以选择该值并将其保存到defaulSharedPreferences

但是在第一次启动PreferenceActivity时，默认值没有加载，我不知道为什么

行为是这样的：当我打开PreferenceActivity时，NumberPickerPreference的摘要显示-1。当我关闭活动并再次打开它时，值保持在-1（只要DefaultSharedReferences在存储的键下没有值）。一旦用户选择了一个值（或通过代码将一个值保存在DefaultSharedReferences下），一切都会工作，并在PreferenceActivity启动时加载该值

    public class NumberPickerPreference extends DialogPreference implements NumberPicker.OnValueChangeListener
    {
        private static final String NAMESPACE="http://schemas.android.com/apk/res/android";

        private NumberPicker mNumberPicker;
        private TextView mTvDialogMessage;
        private Context mCtx;

        private String mDialogMessage;
        private int mDefault;
        private int mMax;
        private int mValue = 0;

        public NumberPickerPreference(Context ctx, AttributeSet attr) { 
            super(ctx, attr); 
            mCtx = ctx;

            //Get XML attributes
            mDialogMessage = attr.getAttributeValue(NAMESPACE,"dialogMessage");
            mDefault = attr.getAttributeIntValue(NAMESPACE,"defaultValue", 2);
            mMax = attr.getAttributeIntValue(NAMESPACE,"max", 20);
        }

        @Override 
        protected View onCreateDialogView() {
            //Create Views
            LinearLayout dialogLayout = new LinearLayout(mCtx);
            mTvDialogMessage = new TextView(mCtx);
            mNumberPicker = new NumberPicker(mCtx);

            //Set View attributes
            dialogLayout.setOrientation(LinearLayout.VERTICAL);
            if (mDialogMessage!=null)
                mTvDialogMessage.setText(mDialogMessage);
            dialogLayout.addView(mTvDialogMessage);
            mNumberPicker.setOnValueChangedListener(this);
            dialogLayout.addView(mNumberPicker, new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
            if (shouldPersist())
                mValue = getPersistedInt(mDefault);
            mNumberPicker.setMaxValue(mMax);
            mNumberPicker.setMinValue(1);
            mNumberPicker.setValue(mValue);
            return dialogLayout;
        }

        @Override 
        protected void onBindDialogView(View v) {
            super.onBindDialogView(v);
            mNumberPicker.setMaxValue(mMax);
            mNumberPicker.setMinValue(1);
            mNumberPicker.setValue(mValue);     
            setSummary(mValue);
        }

        @Override
        protected void onSetInitialValue(boolean restore, Object defaultValue)  
        {
            super.onSetInitialValue(restore, defaultValue);
            if (restore) 
                mValue = shouldPersist() ? getPersistedInt(mDefault) : 2;
            else 
                mValue = (Integer)defaultValue;
            if (mNumberPicker!=null)
                mNumberPicker.setValue(mValue);
            setSummary(mValue);
        }

        public void setSummary(int value) {
            CharSequence summary = getSummary();
            value=getPersistedInt(-1);
            if (summary == null) {
                setSummary(Integer.toString(value));
            } else {
                setSummary(String.format(summary.toString(), value));
            }
        }

        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            setSummary(newVal);
            if (shouldPersist())
                persistInt(newVal);
            callChangeListener(new Integer(newVal));    
        }
    }

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尝试在persistInt（newVal）之后添加notifyChanged（）

我遇到了相同的问题。不确定是否正确，但正在呼叫

设置默认值（对象）

使用首选项中的默认值，构造函数似乎可以解决这个问题