带有数字选择器的 Android PreferenceActivity 对话框

Question

我已经看到了许多针对这个问题的定制解决方案和答案。我需要一些非常简单的东西，我有一个偏好 Activity ，我所需要的只是其中一个选项将打开带有数字选择器的对话框并保存结果。你能指导我一步一步地完成这个吗？

public class SettingsActivity extends PreferenceActivity
{
    @Override
    protected void onCreate(final Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        getFragmentManager().beginTransaction().replace(android.R.id.content, new MyPreferenceFragment()).commit();
        //requestWindowFeature(Window.FEATURE_NO_TITLE);    
    }

    public static class MyPreferenceFragment extends PreferenceFragment
    {
        @Override
        public void onCreate(final Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            addPreferencesFromResource(R.xml.prefs);

        }
    }

}

XML:

    <SwitchPreference
        android:key="cross"
        android:summaryOff="Cross is invisible"
        android:summaryOn="Cross is visible"
        android:switchTextOff="OFF"
        android:switchTextOn="ON"
        android:title="Cross" 
        android:defaultValue="true"/>

    <SwitchPreference
        android:key="autoP"
        android:summaryOff="App will go to sleep"
        android:summaryOn="App will not go to sleep"
        android:switchTextOff="OFF"
        android:switchTextOn="ON"
        android:title="Always On" 
        android:defaultValue="true"/>

    <SwitchPreference
        android:key="tempD"
        android:summaryOff="Temprature not displayed"
        android:summaryOn="Temprature displayed"
        android:switchTextOff="OFF"
        android:switchTextOn="ON"
        android:title="Tempature Display" 
        android:defaultValue="true"/>

    <ListPreference
        android:entries="@array/units"
        android:entryValues="@array/lunits"
        android:key="listUnits"
        android:summary="Units schosssing"
        android:title="Units" android:defaultValue="C"/>

     <!--Need to add button to open dialog-->       

</PreferenceScreen>

数字选择器 XML:

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

    <NumberPicker
        android:id="@+id/numberPicker1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="64dp" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/numberPicker1"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="98dp"
        android:layout_toRightOf="@+id/numberPicker1"
        android:text="Cancel" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button2"
        android:layout_alignBottom="@+id/button2"
        android:layout_marginRight="16dp"
        android:layout_toLeftOf="@+id/numberPicker1"
        android:text="Set" />

</RelativeLayout>

Answer 1

子类 DialogPreference 以构建您自己的 NumberPickerPreference。

我在下面为您实现了一个。它工作得很好，但功能不完整。例如，最小值和最大值是硬编码的常量。这些实际上应该是首选项 xml 声明中的属性。要让它工作，您需要添加一个 attrs.xml 文件来指定您的自定义属性。

有关在库项目中支持自定义 xml 属性的 NumberPicker 首选项小部件的完整实现以及演示如何使用它的演示应用程序，请参阅 GitHub:https://github.com/Alobar/AndroidPreferenceTest

您可以将该小部件用作任何其他首选项小部件，除非您必须完全限定名称:

preferences.xml

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

    <com.example.preference.NumberPickerPreference
        android:key="key_number"
        android:title="Give me a number"
        android:defaultValue="55" />

</PreferenceScreen>

NumberPickerPreference.java

package com.example.preference;

import android.content.Context;
import android.content.res.TypedArray;
import android.preference.DialogPreference;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.NumberPicker;

/**
 * A {@link android.preference.Preference} that displays a number picker as a dialog.
 */
public class NumberPickerPreference extends DialogPreference {

    // allowed range
    public static final int MAX_VALUE = 100;
    public static final int MIN_VALUE = 0;
    // enable or disable the 'circular behavior'
    public static final boolean WRAP_SELECTOR_WHEEL = true; 

    private NumberPicker picker;
    private int value;

    public NumberPickerPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public NumberPickerPreference(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected View onCreateDialogView() {
        FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        layoutParams.gravity = Gravity.CENTER;

        picker = new NumberPicker(getContext());
        picker.setLayoutParams(layoutParams);

        FrameLayout dialogView = new FrameLayout(getContext());
        dialogView.addView(picker);

        return dialogView;
    }

    @Override
    protected void onBindDialogView(View view) {
        super.onBindDialogView(view);
        picker.setMinValue(MIN_VALUE);
        picker.setMaxValue(MAX_VALUE);
        picker.setWrapSelectorWheel(WRAP_SELECTOR_WHEEL);
        picker.setValue(getValue());
    }

    @Override
    protected void onDialogClosed(boolean positiveResult) {
        if (positiveResult) {
            picker.clearFocus();
            int newValue = picker.getValue();
            if (callChangeListener(newValue)) {
                setValue(newValue);
            }
        }
    }

    @Override
    protected Object onGetDefaultValue(TypedArray a, int index) {
        return a.getInt(index, MIN_VALUE);
    }

    @Override
    protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
        setValue(restorePersistedValue ? getPersistedInt(MIN_VALUE) : (Integer) defaultValue);
    }

    public void setValue(int value) {
        this.value = value;
        persistInt(this.value);
    }

    public int getValue() {
        return this.value;
    }
}