Android自定义 view属性_xmlns:myattr=-优快云博客

本文介绍如何在Android中使用自定义样式属性，并通过这些属性来改变视图的外观和行为，具体展示了如何实现一个圆形视图并设置其半径和颜色。

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第一种

/MainActivity/res/values/attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="MyCircle">
        <attr name="radius" format="integer"/>
        <attr name="mycolor" format="reference|color"/>
    </declare-styleable>
</resources>

/MainActivity/src/com/ch/myviews/MyCircle.java

package com.ch.myviews;

import com.ch.myviewattr.R;

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

public class MyCircle extends View {
    private Paint paint;
    private int radius;
   
    public MyCircle(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
        //获得自定义的属性，即获得自定义的半径
        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.MyCircle);
        radius = ta.getInt(R.styleable.MyCircle_radius, 0);
        
      
    }
    //绘制的方法
    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        paint = new Paint();
        paint.setColor(Color.RED);
        
//        canvas.drawColor(Color.BLACK);
        canvas.drawCircle(getMeasuredWidth()/2, getMeasuredHeight()/2, radius, paint);
        super.onDraw(canvas);
    }
    
    

}

/MainActivity/res/layout/activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:myattr="http://schemas.android.com/apk/res/com.ch.myviewattr"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <com.ch.myviews.MyCircle
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        myattr:radius="200"
        />

</RelativeLayout>

第二种

/MainActivity/res/values/attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="MyCircle">
        <attr name="radius" format="integer"/>
        <attr name="mycolor" format="reference|color"/>
    </declare-styleable>
</resources>

/MainActivity/src/com/ch/myviews/MyCircle.java

package com.ch.myviews;

import com.ch.myviewattr.R;

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

public class MyCircle extends View {
    private Paint paint;
    private int radius;
    private final static String NAMESPACE = "aaa1407a";
    public MyCircle(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
        //获得自定义的属性，即获得自定义的半径
    
        radius = attrs.getAttributeIntValue(NAMESPACE, "radius", 0);
    }
    //绘制的方法
    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        paint = new Paint();
        paint.setColor(Color.RED);
        
//        canvas.drawColor(Color.BLACK);
        canvas.drawCircle(getMeasuredWidth()/2, getMeasuredHeight()/2, radius, paint);
        super.onDraw(canvas);
    }
    
    

}

/MainActivity/res/layout/activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:myattr="aaa1407a"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <com.ch.myviews.MyCircle
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        myattr:radius="200"
        />

</RelativeLayout>