前言
根据启舰 的博客所学习的自定义View。
什么是自定义控件属性？
首先，咱们先看看这个代码
croosRoads:age="18"
这可不是系统自带的，而是自定义的属性，那么怎么做呢？利用XML中的declare-styleable标签就可以啦~
下面就来用declare-styleable来封装控件吧
一、具体使用方法
1. 在res/values下创建attrs.xml文件
<?xml version="1.0" encoding="utf-8"?>
<resources>
<!--为MineView添加自定义属性-->
<declare-styleable name="MineView">
<attr name="img" format="reference" />
<attr name="height" format="dimension" />
<!--表示既可以自定义color，如##ff00ff，也可以引用，如@color/XXX-->
<attr name="paintColor" format="color|reference" />
<attr name="radius" format="integer">
<enum name="small" value="3"/>
<enum name="large" value="50"/>
</attr>
</declare-styleable>
</resources>
**2. 布局文件中引用 **
<com.qianqian.demo.viewdemo.MineView
android:layout_width="match_parent"
android:layout_centerInParent="true"
android:layout_height="match_parent"
crossRoads:height="300dp"
android:textColor="#fff"
crossRoads:img="@mipmap/bear"
crossRoads:paintColor="@color/colorAccent"
crossRoads:radius="large"
/>
<!-- 也可以这样 crossRoads:paintColor="#0fff00"-->
3. MineView中获取这些值
public class MineView extends View {
private Paint paint;
int color;
float radius;
Drawable drawable;
float height;
public MineView(Context context) {
this(context, null);
}
public MineView(Context context, AttributeSet attrs) {
super(context, attrs);
paint = new Paint();
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.MineView);
color = typedArray.getColor(R.styleable.MineView_paintColor, Color.BLUE);
paint.setColor(color);
radius = typedArray.getInteger(R.styleable.MineView_radius, 1);
drawable = typedArray.getDrawable(R.styleable.MineView_img);
height = typedArray.getDimension(R.styleable.MineView_height, 100); //获取的值为450px
//必须回收
typedArray.recycle();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//获取宽高
int measureHeight=MeasureSpec.getSize(heightMeasureSpec);
int measureWidth = MeasureSpec.getSize(widthMeasureSpec);
//获取高度的属性
int mode=MeasureSpec.getMode(heightMeasureSpec);
//如果属性是MATCH_PARENT或者是具体的值,就使用自定义的高度
if (mode==MeasureSpec.EXACTLY) {
setMeasuredDimension(measureWidth, (int) height);
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
setLayerType(LAYER_TYPE_SOFTWARE, null);//对单独的View在运行时阶段禁用硬件加速
canvas.drawColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(2);
canvas.drawCircle(100, 100, radius, paint);
BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
Bitmap bitmap = bitmapDrawable.getBitmap();
canvas.drawBitmap(bitmap, 100, 200, paint);
}
}
效果图
二、declare-styleable标签属性用法
1. reference: 参考某一资源ID
<declare-styleable name = "名称">
<attr name = "background" format = "reference" />
</declare-styleable>
<ImageView
android:layout_width = "42dip"
android:layout_height = "42dip"
android:background = "@drawable/图片ID"/>
**2.color: 颜色值 **
<declare-styleable name = "名称">
<attr name = "textColor" format = "color" />
</declare-styleable>
<TextView
android:layout_width = "42dip"
android:layout_height = "42dip"
android:textColor = "#00FF00"/>
3.boolean:布尔值
<declare-styleable name = "名称">
<attr name = "focusable" format = "boolean" />
</declare-styleable>
<Button
android:layout_width = "42dip"
android:layout_height = "42dip"
android:focusable = "true"/>
4. dimension:尺寸值
<declare-styleable name = "名称">
<attr name = "layout_width" format = "dimension" />
</declare-styleable>
<Button
android:layout_width = "42dip"
android:layout_height = "42dip"/>
5.float：浮点值
<declare-styleable name = "AlphaAnimation">
<attr name = "fromAlpha" format = "float" />
<attr name = "toAlpha" format = "float" />
</declare-styleable>
<alpha
android:fromAlpha = "1.0"
android:toAlpha = "0.7"/>
6. integer: 整型值
<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>
<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
<declare-styleable name = "MapView">
<attr name = "apiKey" format = "string" />
</declare-styleable>
<com.google.android.maps.MapView
android:layout_width = "fill_parent"
android:layout_height = "fill_parent"
android:apiKey = "haha" />
8. fraction：百分数
<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>
<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
<declare-styleable name="名称">
<attr name="orientation">
<enum name="horizontal" value="0" />
<enum name="vertical" value="1" />
</attr>
</declare-styleable>
<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
<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>
<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>
11.定义多种类型
<declare-styleable name = "名称">
<attr name = "background" format = "reference|color" />
</declare-styleable>
<ImageView
android:layout_width = "42dip"
android:layout_height = "42dip"
android:background = "@drawable/图片ID|#00FF00"/>
后记
这样子，以后我们写自定义View后，小伙伴们引用的时候就方便多啦！
下面，补充一个小知识：
wrap_content-> MeasureSpec.AT_MOST
match_parent -> MeasureSpec.EXACTLY
具体值 -> MeasureSpec.EXACTLY
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