android中自定义的控件,使用自定义属性attrs.xml

本文介绍如何在Android中创建自定义控件及其属性。通过定义attrs.xml文件内的样式和属性,实现控件属性的自定义,并展示了如何在布局文件中使用这些属性,以及在自定义View中获取和应用这些属性。

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自定义控件,很多时间需要用到自定义的属性

首先在value文件夹中建立attrs.xml文件

添加内容如下

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

    <declare-styleable name="MyGifView">
        <attr name="gif_drawable" format="reference" />
    </declare-styleable>

</resources>

上面定义了一个自定义的属性,名称为MyGifView

其中包括了一个选项 giv_drawable, format类型为reference

在布局文件中,使用自定义属性

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:android_custom="http://schemas.android.com/apk/res/com.org.dengzh"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <com.org.dengzh.MyGifView
        android:id="@+id/iv"
        android:layout_width="300dp"
        android:layout_height="150dip"
        android_custom:gif_drawable="@drawable/test" />
</LinearLayout>

注意
xmlns:android_custom="http://schemas.android.com/apk/res/com.org.dengzh"

这一句, 最后的com.org.dengzh是你这个项目的包名

前面的xmlns:xxxx_xxx是你自己定义的前缀时,使用时 使用 前缀:属性名="值"的形式

android_custom:gif_drawable="@drawable/test"

这里我赋值给属性gif_drawable一张名为test的资源图片


在自定义中,取得赋值的属性的值

下面是一个自定义的可以显示Gif图片的View

package com.org.dengzh;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Movie;
import android.util.AttributeSet;
import android.view.View;

public class MyGifView extends View {
	private long movieStart;
	private Movie movie;
	private int givDrawable;

	public MyGifView(Context context, AttributeSet attrs) {
		super(context, attrs);

		TypedArray mTypedArray = context.obtainStyledAttributes(attrs,
				R.styleable.MyGifView);
		// 获取自定义属性和默认值
		givDrawable = mTypedArray.getResourceId(
				R.styleable.MyGifView_gif_drawable, R.drawable.test);
		movie = Movie.decodeStream(getResources().openRawResource(givDrawable));
	}

	@Override
	protected void onDraw(Canvas canvas) {
		long curTime = android.os.SystemClock.uptimeMillis();
		if (movieStart == 0) {
			movieStart = curTime;
		}
		if (movie != null) {
			int duraction = movie.duration();
			
			int relTime = (int) ((curTime - movieStart) % duraction);
			movie.setTime(relTime);
			movie.draw(canvas, 0, 0);
			invalidate();
		}
		// super.onDraw(canvas);
	}
}

TypedArray mTypedArray = context.obtainStyledAttributes(attrs,
				R.styleable.MyGifView);
		// 获取自定义属性和默认值
		givDrawable = mTypedArray.getResourceId(
				R.styleable.MyGifView_gif_drawable, R.drawable.test);
这两行,首先取得名为MyGifView的属性数组

第二行,取得数组中的名为MyGifView_gif_drawable的属性的值,getResourceId的第二个参数是一个默认值,如果用户没有给giv_drawable赋值,那么就用默认值代替


最后附上format类型如下几种

1. reference:参考某一资源ID。 
    (1)属性定义: 
            <declare-styleable name = "名称"> 
                   <attr name = "background" format = "reference" /> 
            </declare-styleable> 
    (2)属性使用: 
             <ImageView 
                     android:layout_width = "42dip" 
                     android:layout_height = "42dip" 
                     android:background = "@drawable/图片ID" 
                     /> 
2. color:颜色值。 
    (1)属性定义: 
            <declare-styleable name = "名称"> 
                   <attr name = "textColor" format = "color" /> 
            </declare-styleable> 
    (2)属性使用: 
            <TextView 
                     android:layout_width = "42dip" 
                     android:layout_height = "42dip" 
                     android:textColor = "#00FF00" 
                     /> 
3. boolean:布尔值。 
    (1)属性定义: 
            <declare-styleable name = "名称"> 
                   <attr name= "focusable" format = "boolean" /> 
            </declare-styleable> 
4. dimension:尺寸值。 
    (1)属性定义: 
            <declare-styleable name = "名称"> 
                   <attr name = "layout_width" format = "dimension" /> 
            </declare-styleable> 
    (2)属性使用: 
            <Button 
                    android:layout_width = "42dip" 
                    android:layout_height = "42dip" 
                    /> 

5. float:浮点值。 

    (1)属性定义: 

            <declare-styleable name = "AlphaAnimation"> 

                   <attr name = "fromAlpha" format = "float" /> 
                   <attr name = "toAlpha" format = "float" /> 

            </declare-styleable> 

    (2)属性使用: 
            <alpha 
                   android:fromAlpha = "1.0" 
                   android:toAlpha = "0.7" 
                   /> 

6. integer:整型值。 
    (1)属性定义: 
            <declare-styleable name = "AnimatedRotateDrawable"> 
                   <attr name = "visible" /> 
                   <attr name = "frameDuration" format="integer" /> 
                   <attr name = "framesCount" format="integer" /> 
                   <attr name = "pivotX" /> 
                   <attr name = "pivotY" /> 
                   <attr name = "drawable" /> 
            </declare-styleable> 
    (2)属性使用: 
            <animated-rotate 
                   xmlns:android = "http://schemas.android.com/apk/res/android" 
                   android:drawable = "@drawable/图片ID" 
                   android:pivotX = "50%" 
                   android:pivotY = "50%" 
                   android:framesCount = "12" 
                   android:frameDuration = "100" 
                   /> 

7. string:字符串。 
    (1)属性定义: 
            <declare-styleable name = "MapView"> 
                   <attr name = "apiKey" format = "string" /> 
            </declare-styleable> 
    (2)属性使用: 
            <com.google.android.maps.MapView 
                    android:layout_width = "fill_parent" 
                    android:layout_height = "fill_parent" 
                    android:apiKey = "0jOkQ80oD1JL9C6HAja99uGXCRiS2CGjKO_bc_g" 
                    /> 

8. fraction:百分数。 
    (1)属性定义: 
            <declare-styleable name="RotateDrawable"> 
                   <attr name = "visible" /> 
                   <attr name = "fromDegrees" format = "float" /> 
                   <attr name = "toDegrees" format = "float" /> 
                   <attr name = "pivotX" format = "fraction" /> 
                   <attr name = "pivotY" format = "fraction" /> 
                   <attr name = "drawable" /> 
            </declare-styleable> 
    (2)属性使用: 
            <rotate 
                   xmlns:android = "http://schemas.android.com/apk/res/android" 
               android:interpolator = "@anim/动画ID" 
                   android:fromDegrees = "0" 
               android:toDegrees = "360" 
                   android:pivotX = "200%" 
                   android:pivotY = "300%" 
               android:duration = "5000" 
                   android:repeatMode = "restart" 
                   android:repeatCount = "infinite" 
                   /> 

9. enum:枚举值。 

    (1)属性定义: 

            <declare-styleable name="名称"> 
                   <attr name="orientation"> 
                          <enum name="horizontal" value="0" /> 
                          <enum name="vertical" value="1" /> 
                   </attr>            

            </declare-styleable> 

    (2)属性使用: 

            <LinearLayout 

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

10. flag:位或运算。 

     (1)属性定义: 

             <declare-styleable name="名称"> 
                    <attr name="windowSoftInputMode"> 
                            <flag name = "stateUnspecified" value = "0" /> 
                            <flag name = "stateUnchanged" value = "1" /> 
                            <flag name = "stateHidden" value = "2" /> 
                            <flag name = "stateAlwaysHidden" value = "3" /> 
                            <flag name = "stateVisible" value = "4" /> 
                            <flag name = "stateAlwaysVisible" value = "5" /> 
                            <flag name = "adjustUnspecified" value = "0x00" /> 
                            <flag name = "adjustResize" value = "0x10" /> 
                            <flag name = "adjustPan" value = "0x20" /> 
                            <flag name = "adjustNothing" value = "0x30" /> 
                     </attr>         

             </declare-styleable> 

     (2)属性使用: 

            <activity 

                   android:name = ".StyleAndThemeActivity" 
                   android:label = "@string/app_name" 
                   android:windowSoftInputMode = "stateUnspecified | stateUnchanged | stateHidden"> 
                   <intent-filter> 
                          <action android:name = "android.intent.action.MAIN" /> 
                          <category android:name = "android.intent.category.LAUNCHER" /> 
                   </intent-filter> 
             </activity> 

     注意: 
     属性定义时可以指定多种类型值。 
    (1)属性定义: 
            <declare-styleable name = "名称"> 
                   <attr name = "background" format = "reference|color" /> 
            </declare-styleable> 
    (2)属性使用: 
             <ImageView 
                     android:layout_width = "42dip" 
                     android:layout_height = "42dip" 
                     android:background = "@drawable/图片ID|#00FF00" 

                     />

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