有没有办法从XML布局设置NumberPicker的最小值、最大值和默认值?
我在活动代码中执行:
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。
有没有一种方法可以使用XML布局来设置这些?
我遇到了同样的问题,这就是我解决它的方法(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)); } }
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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
你可以试试这个:
<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}"/>
这是Android数据绑定的一部分。因此,您可能需要在应用程序级别build.gradle.中将其设置为true
android {
...
dataBinding {
enabled true
}
}
以下是安卓文档的更新版本
(因此支持主题化和安卓工作室设计师预览)
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>
NumberPickerWithXml.kt:
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()
}
}
}
。。。或NumberPickerWithXml.java(未测试):
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 = getContext().getTheme().obtainStyledAttributes(attrs, R.styleable.NumberPickerWithXml, defStyleAttr, defStyleRes);
try {
this.setMinValue(attributes.getInt(R.styleable.NumberPickerWithXml_minValue, 0));
this.setMaxValue(attributes.getInt(R.styleable.NumberPickerWithXml_maxValue, 0));
this.setValue(attributes.getInt(R.styleable.NumberPickerWithXml_defaultValue, 0));
} finally {
attributes.recycle();
}
}
}
布局中的用法:
<?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>