[AndroidUI]自定义view(二)：实现带说明的图片

参考链接：http://blog.csdn.net/lmj623565791/article/details/24300125

自定义view的步骤：

1.res/values/下新建一个attrs.xml，创建自定义的属性

属性类型可以取：string,color,demension,integer,enum,reference,float,boolean,fraction,flag

2.在布局文件中添加自定义的view，为自定义的属性赋值

自定义的属性属于不同的命名空间

3.为自定义的view重写方法，获取自定义的属性

1.attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
   <attr name="titleText" format="string" />  
    <attr name="titleTextSize" format="dimension" />  
    <attr name="titleTextColor" format="color" />  
    <attr name="image" format="reference" />  
    <attr name="imageScaleType">  
        <enum name="fillXY" value="0" />  
        <enum name="center" value="1" />  
    </attr>  
  
    <declare-styleable name="CustomImageView">  
        <attr name="titleText" />  
        <attr name="titleTextSize" />  
        <attr name="titleTextColor" />  
        <attr name="image" />  
        <attr name="imageScaleType" />  
    </declare-styleable>   
</resources>

2.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    xmlns:custom="http://schemas.android.com/apk/res/com.example.testview2"  
    android:layout_width="match_parent"  
    android:layout_height="match_parent"  
    android:orientation="vertical">  
  
    <com.example.testview2.MyView2   
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_margin="10dp"  
        android:padding="10dp"  
        custom:image="@drawable/ic_launcher"  
        custom:imageScaleType="center"  
        custom:titleText="hello andorid ! "  
        custom:titleTextColor="#ff0000"  
        custom:titleTextSize="30sp"/>
    
    <com.example.testview2.MyView2   
        android:layout_width="100dp"  
        android:layout_height="wrap_content"  
        android:layout_margin="10dp"  
        android:padding="10dp"  
        custom:image="@drawable/ic_launcher"  
        custom:imageScaleType="center"  
        custom:titleText="helloworldwelcome"  
        custom:titleTextColor="#00ff00"  
        custom:titleTextSize="20sp"/>  
        
    <com.example.testview2.MyView2   
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_margin="10dp"  
        android:padding="10dp"  
        custom:image="@drawable/a"  
        custom:imageScaleType="center"  
        custom:titleText="妹子~"  
        custom:titleTextColor="#ff0000"  
        custom:titleTextSize="12sp"/>  
        
</LinearLayout> 

3.

package com.example.testview2;

import java.util.HashSet;
import java.util.Random;
import java.util.Set;

import android.R.integer;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Rect;
import android.text.TextPaint;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.View;
import android.view.View.MeasureSpec;
import android.view.View.OnClickListener;

public class MyView2 extends View {

	private String titleText;
	private int titleTextColor;
	private float titleTextSize;
	private Bitmap image;
	private int imageScaleType;
	
	private static final int IMAGE_SCALE_FITXY = 0;
	private static final int IMAGE_SCALE_CENTER = 1;
	
	private Rect imageRect;//图片的绘制范围
	private Rect textRect;//绘制时控制文本绘制的范围
	private Paint paint;
	
	public MyView2(Context context) {
		super(context);
	}

	//默认的布局文件调用的是两个参数的构造方法
	public MyView2(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public MyView2(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);
		
		TypedArray typedArray = context.getTheme().
			obtainStyledAttributes(attrs, R.styleable.CustomImageView, defStyle, 0);
		
		titleText = typedArray.getString(R.styleable.CustomImageView_titleText);
		titleTextColor = typedArray.getColor(R.styleable.CustomImageView_titleTextColor, Color.BLACK);
		titleTextSize = typedArray.getDimension(R.styleable.CustomImageView_titleTextSize, 80);
		image = BitmapFactory.decodeResource(getResources(), typedArray.getResourceId(R.styleable.CustomImageView_image, 0));
		imageScaleType = typedArray.getInt(R.styleable.CustomImageView_imageScaleType, 0);
		
		imageRect = new Rect();
		textRect = new Rect();
		paint = new Paint();

		paint.setTextSize(titleTextSize);
		paint.getTextBounds(titleText, 0, titleText.length(), textRect);//文本绘制范围
		
		typedArray.recycle();
	}
	
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		int widthMode = MeasureSpec.getMode(widthMeasureSpec);  
	    int widthSize = MeasureSpec.getSize(widthMeasureSpec);  
	    int heightMode = MeasureSpec.getMode(heightMeasureSpec);  
	    int heightSize = MeasureSpec.getSize(heightMeasureSpec);  
	    int width;  
	    int height;
	    
	    if(widthMode == MeasureSpec.EXACTLY)//match_parent, accurate
	    {
	    	width = widthSize;
	    }
	    else
	    {
	    	// 由图片决定的宽  
	        int desireByImg = getPaddingLeft() + getPaddingRight() + image.getWidth();  
	        // 由字体决定的宽  
	        int desireByTitle = getPaddingLeft() + getPaddingRight() + textRect.width();
	        
	    	width = Math.max(desireByImg, desireByTitle);
	    }
	    
	    if(heightMode == MeasureSpec.EXACTLY)
	    {
	    	height = heightSize;
	    }
	    else
	    {
	    	height = getPaddingTop() + getPaddingBottom() + image.getHeight() + textRect.height();
	    }
	    
	    //确定整个控件的宽高
	    setMeasuredDimension(width, height);
	}
	
	@Override
	protected void onDraw(Canvas canvas) {
		//绘制边框
		paint.setStrokeWidth(4);  
		paint.setStyle(Paint.Style.STROKE);  
		paint.setColor(Color.CYAN); 
		canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), paint);
		
		paint.setColor(titleTextColor);  
		paint.setStyle(Style.FILL);
		
		//当前设置的宽度小于字体需要的宽度，将字体改为xxx...
        if (textRect.width() > getMeasuredWidth())  
        {  
            TextPaint paint = new TextPaint(this.paint);  
            String msg = TextUtils.ellipsize(titleText, paint, getMeasuredWidth() - getPaddingLeft() - getPaddingRight(),  
                    TextUtils.TruncateAt.END).toString();  
            canvas.drawText(msg, getPaddingLeft(), getMeasuredHeight() - getPaddingBottom(), this.paint);  
  
        } 
        else
        {
        	//居中,以text的左下角为原点
        	canvas.drawText(titleText, getMeasuredWidth() / 2 - textRect.width() / 2, getMeasuredHeight() - getPaddingBottom(), paint);
        }
		
		
		if(imageScaleType == IMAGE_SCALE_FITXY)
		{
			imageRect.left = getPaddingLeft();  
			imageRect.right = getMeasuredWidth() - getPaddingRight();  
			imageRect.top = getPaddingTop();  
			imageRect.bottom = getMeasuredHeight() - getPaddingBottom() - textRect.height();
		}
		else
		{
			imageRect.left = getMeasuredWidth() / 2 - image.getWidth() / 2;
			imageRect.right = getMeasuredWidth() / 2 + image.getWidth() / 2;
			imageRect.top = getMeasuredHeight() - textRect.height() - image.getHeight() - getPaddingBottom();
			imageRect.bottom = getMeasuredHeight() - textRect.height() - getPaddingBottom();
		}
		canvas.drawBitmap(image, null, imageRect, paint);
	}
}

效果图：