Android自定义属性的使用示例
MainActivity如下:
package cc.testattrs;import android.os.Bundle;import android.app.Activity;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}}
ViewSubclass如下:
package cc.testattrs;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Paint.Style;import android.util.AttributeSet;import android.view.View;/** * Demo描述： * Android自定义属性的使用 * * 注意事项: * 1 在main.xml中声明命名空间 * xmlns:testattr="http://schemas.android.com/apk/res/cc.testattrs" * 其中http://schemas.android.com/apk/res/为固定写法,其后追加包名 * testattr为我们给自定义属性的别名引用 * 2 getDimension(R.styleable.TestAttr_testTextSize, 20); * 第二个参数意思是:假如在xml文件中没有为改属性设值则采用此值. * 其余getXX()方法均类似 * 3 注意getColor()方法中第二个参数的取值,是一个颜色值,在这里很容易错误 * */public class ViewSubclass extends View { private Paint mPaint; private float textSize; private int textColor ;public ViewSubclass(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);}public ViewSubclass(Context context, AttributeSet attrs) {super(context, attrs);mPaint = new Paint();TypedArray typedArray = context.obtainStyledAttributes(attrs,R.styleable.TestAttr);textSize = typedArray.getDimension(R.styleable.TestAttr_testTextSize, 20);textColor = typedArray.getColor(R.styleable.TestAttr_testColor, Color.BLACK);System.out.println("textSize="+textSize+",textColor="+textColor);mPaint.setTextSize(textSize);mPaint.setColor(textColor);//切记recycle()typedArray.recycle();}public ViewSubclass(Context context) {super(context);} @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); mPaint.setStyle(Style.FILL); canvas.drawText("9527", 10, 20, mPaint); }}
main.xml如下:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:testattr="http://schemas.android.com/apk/res/cc.testattrs" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" > <cc.testattrs.ViewSubclass android:layout_width="200dip" android:layout_height="200dip" android:layout_centerInParent="true" testattr:testTextSize="10dip" testattr:testColor="#ff0000" /></RelativeLayout>
attrs.xml如下:
<?xml version="1.0" encoding="utf-8"?><resources> <declare-styleable name="TestAttr"> <attr name="testTextSize" format="dimension"/> <attr name="testColor" format="color"/> </declare-styleable></resources>