Android中attrs.xml文件的使用详解
16lz
2021-12-04
1. attrs.xml 的作用
控件有很多属性,如 android:id、android:layout_width、android:layout_height等,但是这些属性都是系统自带的属性。使用attrs.xml文件,可以自己定义属性,下面我会写些小 demo ,比较好理解
2. 在values文件夹下,新建一个attrs.xml文件
内容如下:
<?xml version="1.0" encoding="utf-8"?><declare-styleable name="MyView"> <attr name="textColor" format="color" /> <attr name="textSize" format="dimension" /> declare-styleable>
其中,
<declare-styleable name="MyView">
表明样式名称为MyView,下面包含了两个自定义属性textColor和textSize,其中textColor是颜色(color)类的属性,textSize是尺寸(dimension)类的属性
3. 自定义 MyView
public class MyView extends View { private Paint mPaint; private static final String mString = "Welcome to BaiYe's blog"; public MyView(Context context) { this(context,null); } public MyView(Context context, AttributeSet attrs) { super(context, attrs); mPaint = new Paint(); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.MyView); int textColor = a.getColor(R.styleable.MyView_textColor, 0XFFFFFFFF); float textSize = a.getDimension(R.styleable.MyView_textSize, 36); mPaint.setTextSize(textSize); mPaint.setColor(textColor); a.recycle(); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); // 设置填充 mPaint.setStyle(Paint.Style.FILL); // 画一个矩形,前俩个是矩形左上角坐标,后面俩个是右下角坐标// mPaint.setColor(Color.BLACK); canvas.drawRect(new Rect(10, 10, 100, 100), mPaint); // 绘制文字 canvas.drawText(mString, 60, 410, mPaint); }}
- 首先从 R.styleable.CustomView 获得了TypedArray变量
- 再用getColor(),getDimension()等方法获取相应的属性值,属性格式为“样式名_属性名”,属性后面的参数是默认值。
- 获得属性值以后,就可以应用这些属性值。
- recycle()方法用于返回信号给资源(不懂什么意思)
4. xml 内容
<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:test="http://schemas.android.com/apk/res-auto"//一定记得添加前缀 android:id="@+id/activity_attrs_actiity" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.lizi.newset.CustomView.attrs.AttrsActivity"> <com.lizi.newset.CustomView.attrs.MyView android:id="@+id/myView" android:layout_height="match_parent" android:layout_width="wrap_content" test:textSize="50px" test:textColor="#ff00ff"/> />RelativeLayout>
xmlns:test=”http://schemas.android.com/apk/res-auto”一定要添加,添加之后才能在xml中自定义属性
5. 自定义属性
格式如上,其中“xmlns:test”冒号后面是标签名,在下面使用时(只对当前文件可用)
<TextView test:属性名/>
5.1 reference:参考某一资源ID
<declare-styleable name = "名称"> "background" format = "reference" />declare-styleable>eg:"42dip" android:layout_height = "42dip" android:background = "@drawable/图片ID" />
5.2 color:颜色值
<declare-styleable name = "名称"> "textColor" format = "color" />declare-styleable>eg: "42dip" android:layout_height = "42dip" android:textColor = "#00FF00" />
5.3 boolean:布尔值
<declare-styleable name = "名称"> "focusable" format = "boolean" />declare-styleable>eg:
5.4 dimension:尺寸值
"名称"> "layout_width" format = "dimension" /> eg:<com.lizi.newset.CustomView.attrs.MyView android:id="@+id/myView" android:layout_height="match_parent" android:layout_width="wrap_content" test:textSize="50px" test:textColor="#ff00ff"/>
5.5 float:浮点值
name = "AlphaAnimation"> name = "fromAlpha" format = "float" /> name = "toAlpha" format = "float" /> eg:"1.0" android:toAlpha = "0.7"/>
5.6 string:字符串
"MapView"> "apiKey" format = "string" /> eg:<com.google.android.maps.MapView android:layout_width = "fill_parent" android:layout_height = "fill_parent" android:apiKey = "0jOkQ80oD1JL9C6HAja99uGXCRiS2CGjKO_bc_g" />
5.7 integer:整型值 || fraction:百分数
name = "AnimatedRotateDrawable"> name = "visible" /> name = "frameDuration" format="integer" /> name = "framesCount" format="integer" /> name = "pivotX" format = "fraction"/> name = "pivotY" format = "fraction"/> name = "drawable" /> eg:"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" />
5.8 enum:枚举值
"名称"> "orientation"> <enum name="horizontal" value="0" /> <enum name="vertical" value="1" /> eg:"http://schemas.android.com/apk/res/android" android:orientation = "vertical" android:layout_width = "fill_parent" android:layout_height = "fill_parent" >
5.9 flag 位或运算
name="名称"> name="windowSoftInputMode"> name = "stateUnspecified" value = "0" /> name = "stateUnchanged" value = "1" /> name = "stateHidden" value = "2" /> name = "stateAlwaysHidden" value = "3" /> name = "stateVisible" value = "4" /> name = "stateAlwaysVisible" value = "5" /> name = "adjustUnspecified" value = "0x00" /> name = "adjustResize" value = "0x10" /> name = "adjustPan" value = "0x20" /> name = "adjustNothing" value = "0x30" /> eg:name = ".StyleAndThemeActivity" android:label = "@string/app_name" android:windowSoftInputMode = "stateUnspecified | stateUnchanged | stateHidden"> name = "android.intent.action.MAIN" /> name = "android.intent.category.LAUNCHER" />
6. 属性定义时可以同时定义多种类型值
<declare-styleable name = "名称"> "background" format = "reference|color" />declare-styleable>eg:"42dip" android:layout_height = "42dip" android:background = "@drawable/图片ID|#00FF00" />
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