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Android中的自定义View和自定义属性

文章目录

对于自定义属性,需要遵循以下几步,就可以实现:

  1. 自定义一个IcoLayout(extends View )类
  2. 编写values/attrs.xml,在其中编写styleable和item等标签元素
  3. 在布局文件中IcoLayout使用自定义的属性(注意namespace)
  4. 在IcoLayout的构造方法中通过TypedArray获取

一:在res/values新增一个attrs.xml文件

并写入如下内容:

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="ico_layout">
        <attr name="layout_ico" format="reference"></attr>
        <attr name="layout_text" format="string"></attr>
    </declare-styleable>

</resources>

二:在xml布局中使用

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res/com.bokezhi.attrs"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

<!-- 
     xmlns:app="http://schemas.android.com/apk/res/com.bokezhi.attrs"
     xmlns:app中的app可以换成其他的比如xmlns:lys等等
     后面的com.bokezhi.attrs是改程序的主包名,不是自定义View的包名,切记!!!!
  -->

    <com.bokezhi.view.IcoLayout
        android:layout_width="587dp"
        android:layout_height="53dp"
        app:layout_ico="@drawable/video_bg"
        app:layout_text="@string/hello_world" >
    </com.bokezhi.view.IcoLayout>

</RelativeLayout>

三:写自定义View并获取attrs中的值

package com.bokezhi.view;

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

import com.bokezhi.attrs.R;

public class IcoLayout extends View {

	private Bitmap icoBitmap = null;
	private String icoText = null;

	// 字体大小
	private int textSize = 30;
	// 自定位置调节
	private int text_margin_left = 80;
	private int text_margin_top = 37;
	// 需要布局的高宽
	private final int DEFAULT_WIDTH = 587;
	private final int DEFAULT_HEIGHT = 52;
	private Paint mPaint = null;

	public IcoLayout(Context context) {
		this(context, null);
	}

	public IcoLayout(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public IcoLayout(Context context, AttributeSet attrs, int defStyleAttr) {
		super(context, attrs, defStyleAttr);

		initUI(context, attrs);
	}

	private void initUI(Context context, AttributeSet attrs) {
		TypedArray typedArray = context.obtainStyledAttributes(attrs,
				R.styleable.ico_layout);
		icoBitmap = ((BitmapDrawable) typedArray
				.getDrawable(R.styleable.ico_layout_layout_ico)).getBitmap();
		icoText = (String) typedArray
				.getText(R.styleable.ico_layout_layout_text);
		// 这句一定需要 释放资源
		typedArray.recycle();

		// 初始化画刷
		mPaint = new Paint();

		return;
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		// TODO Auto-generated method stub
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		int width = getMesureSize(DEFAULT_WIDTH, widthMeasureSpec);
		int height = getMesureSize(DEFAULT_HEIGHT, heightMeasureSpec);
		setMeasuredDimension(width, height);
	}

	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		// 画ico 图片
		canvas.drawBitmap(icoBitmap, 0, 0, mPaint);
		// 或ico 文本
		mPaint.setColor(Color.WHITE);
		mPaint.setTextSize(textSize);
                //这里文字居位置数据是测试的,没有可靠性! 需要根据字体大小而调节
		canvas.drawText(icoText, text_margin_left, text_margin_top, mPaint);
	}

	private int getMesureSize(int default_size, int measureSpec) {
		int current_size = default_size;
		int mode = MeasureSpec.getMode(measureSpec);
		int size = MeasureSpec.getSize(measureSpec);
		switch (mode) {
		case MeasureSpec.AT_MOST:
			current_size = size;
			break;
		case MeasureSpec.EXACTLY:
			current_size = size;
			break;
		case MeasureSpec.UNSPECIFIED:
			current_size = default_size;
			break;
		default:
			break;
		}
		return current_size;
	}
}

四:attrs内容补充说明

下面是一些关于attrs属性值的定义说明

 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"  

本文部分内容摘抄于《Android高手进阶篇2-自定义AttributeSet属性 》和《Android 深入理解Android中的自定义属性

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