Android高级用法之attrs使用

xml中自定义控件，如果使用自定义的属性，可在values中定义一个attrs.xml。

1、添加文件attrs.xml，位于res\values目录下：

1 <?xml version="1.0" encoding="utf-8"?>
2 <resources>
3     <declare-styleable name="myView">
4         <attr name="textColor" format="color"/>
5         <attr name="textSize" format="dimension"/>
6     </declare-styleable>
7 </resources>

2、创建自定义控件：

1 package com.szy.custom;
2
3 import com.szy.custom.R;
4
5 import android.content.Context;
6 import android.content.res.TypedArray;
7 import android.graphics.Canvas;
8 import android.graphics.Color;
9 import android.graphics.Paint;
10 import android.graphics.Rect;
11 import android.graphics.Paint.Style;
12 import android.util.AttributeSet;
13 import android.view.View;
14
15 public class MyView extends View {
16     private Paint myPaint;
17     private static final String myString = "Hello CustomView!";
18
19     public MyView(Context context) {
20         super(context);
21         // TODO Auto-generated constructor stub
22      }
23
24     public MyView(Context context, AttributeSet attr) {
25         super(context, attr);
26          myPaint = new Paint();
27          TypedArray a = context.obtainStyledAttributes(attr, R.styleable.myView);//TypedArray是一个数组容器
28         float textSize = a.getDimension(R.styleable.myView_textSize, 30);//防止在XML文件里没有定义，就加上了默认值30
29         int textColor = a.getColor(R.styleable.myView_textColor, 0xFFFFFFFF);//同上,这里的属性是:名字_属性名
30          myPaint.setTextSize(textSize);
31          myPaint.setColor(textColor);
32          a.recycle();//我的理解是：返回以前取回的属性，供以后使用。以前取回的可能就是textSize和textColor初始化的那段
33      }
34     @Override
35     protected void onDraw(Canvas canvas) {
36         // TODO Auto-generated method stub
37         super.onDraw(canvas);
38         //myPaint = new Paint();
39          myPaint.setColor(Color.RED);
40          myPaint.setStyle(Style.FILL);
41
42          canvas.drawRect(new Rect(10,10,100,100), myPaint);
43          myPaint.setColor(Color.WHITE);
44          canvas.drawText(myString, 10, 100, myPaint);
45      }
46 }

3、在Activity布局文件中使用自定义控件：

1 <?xml version="1.0" encoding="utf-8"?>
2 <LinearLayout xmlns:android="<a href="http://schemas.android.com/apk/res/android">http://schemas.android.com/apk/res/android</a>"
3     xmlns:test="<a href="http://schemas.android.com/apk/res/com.szy.custom">http://schemas.android.com/apk/res/com.szy.custom</a>"
4     android:orientation="vertical"
5     android:layout_width="fill_parent"
6     android:layout_height="fill_parent"
7     >
8 <TextView
9     android:layout_width="fill_parent"
10     android:layout_height="wrap_content"
11     android:text="@string/hello"
12     />
13 <com.adnroid.test.MyView
14     android:layout_width="fill_parent"
15     android:layout_height="fill_parent"
16     test:textSize="10px"
17     test:textColor="#fff"
18     />
19 </LinearLayout>

 

附：Android中自定义属性的格式详解

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>

    （2）属性使用：

            <Button

                    android:layout_width = "42dip"

                    android:layout_height = "42dip"

                    android:focusable = "true"

                    />

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"

                     />