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Android NumberPicker：从XML设置最小值、最大值、默认值

android xml layout

Android NumberPicker：从XML设置最小值、最大值、默认值,android,xml,layout,numberpicker,Android,Xml,Layout,Numberpicker,是否有一种方法可以从XML布局中设置a的最小值、最大值和默认值 我是在活动代码中进行的： np = (NumberPicker) findViewById(R.id.np); np.setMaxValue(120); np.setMinValue(0); np.setValue(30); XML显然更合适，因为它定义的是属性，而不是行为 有没有办法使用XML布局设置这些内容？我也遇到了同样的问题，我就是这样解决的（根据MKJParekh的评论）： 我创建了自己的NumberPicker类 pa

是否有一种方法可以从XML布局中设置a的最小值、最大值和默认值

我是在活动代码中进行的：

np = (NumberPicker) findViewById(R.id.np);
np.setMaxValue(120);
np.setMinValue(0);
np.setValue(30);
XML显然更合适，因为它定义的是属性，而不是行为

有没有办法使用XML布局设置这些内容？

我也遇到了同样的问题，我就是这样解决的（根据MKJParekh的评论）：

  • 我创建了自己的NumberPicker类

    package com.exaple.project;

import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build;
import android.util.AttributeSet;
import android.widget.NumberPicker;

@TargetApi(Build.VERSION_CODES.HONEYCOMB)//For backward-compability
public class MyNumberPicker extends NumberPicker {

    public MyNumberPicker(Context context) {
        super(context);
    }

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

    public MyNumberPicker(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        processAttributeSet(attrs);
    }
    private void processAttributeSet(AttributeSet attrs) {
        //This method reads the parameters given in the xml file and sets the properties according to it
        this.setMinValue(attrs.getAttributeIntValue(null, "min", 0));
        this.setMaxValue(attrs.getAttributeIntValue(null, "max", 0));
    }
}
  • 现在，您可以在xml布局文件中使用此NumberPicker

    <com.exaple.project.myNumberPicker
    android:id="@+id/numberPicker1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:orientation="vertical"
    max="100"
    min="1" />
    • 感谢MKJParekh的有用评论

    以下是更新版 （因此支持主题化和Android Studio designer预览）

    values/attrs.xml:

    <?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="NumberPickerWithXml">
        <attr name="maxValue" format="integer" />
        <attr name="minValue" format="integer" />
        <attr name="defaultValue" format="integer" />
    </declare-styleable>

</resources>

    package com.example.library.ui

import android.content.Context
import android.util.AttributeSet
import android.widget.NumberPicker
import com.example.library.ui.R

class NumberPickerWithXml : NumberPicker {

    constructor(context: Context) : super(context)

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        processXmlAttributes(attrs)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
        processXmlAttributes(attrs, defStyleAttr)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes) {
        processXmlAttributes(attrs, defStyleAttr, defStyleRes)
    }

    private fun processXmlAttributes(attrs: AttributeSet, defStyleAttr: Int = 0, defStyleRes: Int = 0) {
        val attributes = context.theme.obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes)

        try {
            this.minValue = attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0)
            this.maxValue = attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0)
            this.value = attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0)
        } finally {
            attributes.recycle()
        }
    }

}

    package com.example.library.ui

import android.content.Context
import android.util.AttributeSet
import android.widget.NumberPicker
import com.example.library.ui.R

public class NumberPickerWithXml extends NumberPicker {

    public NumberPickerWithXml(Context context) {
        super(context);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs) {
        super(context, attrs);
        processXmlAttributes(attrs, 0, 0);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs, int: defStyleAttr) {
        super(context, attrs, defStyleAttr);
        processXmlAttributes(attrs, defStyleAttr, 0);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs, int: defStyleAttr, int: defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        processXmlAttributes(attrs, defStyleAttr, defStyleRes);
    }

    private void processXmlAttributes(AttributeSet: attrs, int: defStyleAttr, int: defStyleRes) {
        TypedArray attributes = context.getTheme().obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes)

        try {
            this.minValue = attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0);
            this.maxValue = attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0);
            this.value = attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0);
        } finally {
            attributes.recycle();
        }
    }

}

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <com.example.library.ui.NumberPickerWithXml
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        custom:defaultValue="30"
        custom:maxValue="120"
        custom:minValue="0" />

</LinearLayout>
    …或NumberPickerWithXml.java（未经测试）：

    <?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="NumberPickerWithXml">
        <attr name="maxValue" format="integer" />
        <attr name="minValue" format="integer" />
        <attr name="defaultValue" format="integer" />
    </declare-styleable>

</resources>

    package com.example.library.ui

import android.content.Context
import android.util.AttributeSet
import android.widget.NumberPicker
import com.example.library.ui.R

class NumberPickerWithXml : NumberPicker {

    constructor(context: Context) : super(context)

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        processXmlAttributes(attrs)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
        processXmlAttributes(attrs, defStyleAttr)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes) {
        processXmlAttributes(attrs, defStyleAttr, defStyleRes)
    }

    private fun processXmlAttributes(attrs: AttributeSet, defStyleAttr: Int = 0, defStyleRes: Int = 0) {
        val attributes = context.theme.obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes)

        try {
            this.minValue = attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0)
            this.maxValue = attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0)
            this.value = attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0)
        } finally {
            attributes.recycle()
        }
    }

}

    package com.example.library.ui

import android.content.Context
import android.util.AttributeSet
import android.widget.NumberPicker
import com.example.library.ui.R

public class NumberPickerWithXml extends NumberPicker {

    public NumberPickerWithXml(Context context) {
        super(context);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs) {
        super(context, attrs);
        processXmlAttributes(attrs, 0, 0);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs, int: defStyleAttr) {
        super(context, attrs, defStyleAttr);
        processXmlAttributes(attrs, defStyleAttr, 0);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs, int: defStyleAttr, int: defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        processXmlAttributes(attrs, defStyleAttr, defStyleRes);
    }

    private void processXmlAttributes(AttributeSet: attrs, int: defStyleAttr, int: defStyleRes) {
        TypedArray attributes = context.getTheme().obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes)

        try {
            this.minValue = attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0);
            this.maxValue = attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0);
            this.value = attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0);
        } finally {
            attributes.recycle();
        }
    }

}

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <com.example.library.ui.NumberPickerWithXml
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        custom:defaultValue="30"
        custom:maxValue="120"
        custom:minValue="0" />

</LinearLayout>
    布局中的用法：

    <?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="NumberPickerWithXml">
        <attr name="maxValue" format="integer" />
        <attr name="minValue" format="integer" />
        <attr name="defaultValue" format="integer" />
    </declare-styleable>

</resources>

    package com.example.library.ui

import android.content.Context
import android.util.AttributeSet
import android.widget.NumberPicker
import com.example.library.ui.R

class NumberPickerWithXml : NumberPicker {

    constructor(context: Context) : super(context)

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        processXmlAttributes(attrs)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
        processXmlAttributes(attrs, defStyleAttr)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes) {
        processXmlAttributes(attrs, defStyleAttr, defStyleRes)
    }

    private fun processXmlAttributes(attrs: AttributeSet, defStyleAttr: Int = 0, defStyleRes: Int = 0) {
        val attributes = context.theme.obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes)

        try {
            this.minValue = attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0)
            this.maxValue = attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0)
            this.value = attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0)
        } finally {
            attributes.recycle()
        }
    }

}

    package com.example.library.ui

import android.content.Context
import android.util.AttributeSet
import android.widget.NumberPicker
import com.example.library.ui.R

public class NumberPickerWithXml extends NumberPicker {

    public NumberPickerWithXml(Context context) {
        super(context);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs) {
        super(context, attrs);
        processXmlAttributes(attrs, 0, 0);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs, int: defStyleAttr) {
        super(context, attrs, defStyleAttr);
        processXmlAttributes(attrs, defStyleAttr, 0);
    }

    public NumberPickerWithXml(Context context, AttributeSet: attrs, int: defStyleAttr, int: defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        processXmlAttributes(attrs, defStyleAttr, defStyleRes);
    }

    private void processXmlAttributes(AttributeSet: attrs, int: defStyleAttr, int: defStyleRes) {
        TypedArray attributes = context.getTheme().obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes)

        try {
            this.minValue = attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0);
            this.maxValue = attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0);
            this.value = attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0);
        } finally {
            attributes.recycle();
        }
    }

}

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <com.example.library.ui.NumberPickerWithXml
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        custom:defaultValue="30"
        custom:maxValue="120"
        custom:minValue="0" />

</LinearLayout>
    您可以尝试以下方法：

    <NumberPicker
  android:id="@+id/number_picker"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  app:minValue="@{0}"
  app:maxValue="@{120}"
  app:value="@{30}"/>
    您可能需要自定义NumberPicker，然后在任何地方使用它MyNumberPicker…在MyNumberPicker的构造函数中获取所有属性集和设置值…@MKJParekh您知道如何为时间选择器设置setMaxValue setMinValue吗？很好用，谢谢分享。在Eclipse中使用图形布局编辑器时请注意：如果您在此处更改任何内容，则会删除自定义属性（如min和max），您必须再次手动添加它们。请注意，最好在
    res/values/attrs.XML
    中定义自定义XML属性，如中所述。这还使IDE/布局编辑器能够识别自定义属性。文档还说，不应直接使用
    属性集
    （如此处所示），而应检索
    类型Darray
    。感谢分享。非常惊讶Google“忘记”将这些基本属性放在基类中。非常感谢，您还可以重写setValue，以便在XML文件中进行设置。