自定义View（一）

一.获取属性

1.资源文件定义attr.xml

派生到我的代码片

      
    <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>  

    /** 
         * 初始化所特有自定义类型 
         *  
         * @param context 
         * @param attrs 
         * @param defStyle 
         */  
        public CustomImageView(Context context, AttributeSet attrs, int defStyle)  
        {  
            super(context, attrs, defStyle);  

            TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomImageView, defStyle, 0);  

            int n = a.getIndexCount();  

            for (int i = 0; i < n; i++)  
            {  
                int attr = a.getIndex(i);  

                switch (attr)  
                {  
                case R.styleable.CustomImageView_image:  
                    mImage = BitmapFactory.decodeResource(getResources(), a.getResourceId(attr, 0));  
                    break;  
                case R.styleable.CustomImageView_imageScaleType:  
                    mImageScale = a.getInt(attr, 0);  
                    break;  
                case R.styleable.CustomImageView_titleText:  
                    mTitle = a.getString(attr);  
                    break;  
                case R.styleable.CustomImageView_titleTextColor:  
                    mTextColor = a.getColor(attr, Color.BLACK);  
                    break;  
                case R.styleable.CustomImageView_titleTextSize:  
                    mTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,  
                            16, getResources().getDisplayMetrics()));  
                    break;  

                }  
            }  
            a.recycle();  
            rect = new Rect();  
            mPaint = new Paint();  
            mTextBound = new Rect();  
            mPaint.setTextSize(mTextSize);  
            // 计算了描绘字体需要的范围  
            mPaint.getTextBounds(mTitle, 0, mTitle.length(), mTextBound);  

        }  

二.测量的方法

重新ondMeasure的方法，并根据是否视频父容器或者子view的图片或文字设置大小

    @Override  
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)  
    {  
        // super.onMeasure(widthMeasureSpec, heightMeasureSpec);  

        /** 
         * 设置宽度 
         */  
        int specMode = MeasureSpec.getMode(widthMeasureSpec);  
        int specSize = MeasureSpec.getSize(widthMeasureSpec);  

        if (specMode == MeasureSpec.EXACTLY)// match_parent , accurate  
        {  
            Log.e("xxx", "EXACTLY");  
            mWidth = specSize;  
        } else  
        {  
            // 由图片决定的宽  
            int desireByImg = getPaddingLeft() + getPaddingRight() + mImage.getWidth();  
            // 由字体决定的宽  
            int desireByTitle = getPaddingLeft() + getPaddingRight() + mTextBound.width();  

            if (specMode == MeasureSpec.AT_MOST)// wrap_content  
            {  
                int desire = Math.max(desireByImg, desireByTitle);  
                mWidth = Math.min(desire, specSize);  
                Log.e("xxx", "AT_MOST");  
            }  
        }  

        /*** 
         * 设置高度 
         */  

        specMode = MeasureSpec.getMode(heightMeasureSpec);  
        specSize = MeasureSpec.getSize(heightMeasureSpec);  
        if (specMode == MeasureSpec.EXACTLY)// match_parent , accurate  
        {  
            mHeight = specSize;  
        } else  
        {  
            int desire = getPaddingTop() + getPaddingBottom() + mImage.getHeight() + mTextBound.height();  
            if (specMode == MeasureSpec.AT_MOST)// wrap_content  
            {  
                mHeight = Math.min(desire, specSize);  
            }  
        }  
        setMeasuredDimension(mWidth, mHeight);  

    }  

三.重写draw的方法，其实

    @Override  
        protected void onDraw(Canvas canvas)  
        {  
            // super.onDraw(canvas);  
            /** 
             * 边框 
             */  
            mPaint.setStrokeWidth(4);  
            mPaint.setStyle(Paint.Style.STROKE);  
            mPaint.setColor(Color.CYAN);  
            canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), mPaint);  

            rect.left = getPaddingLeft();  
            rect.right = mWidth - getPaddingRight();  
            rect.top = getPaddingTop();  
            rect.bottom = mHeight - getPaddingBottom();  

            mPaint.setColor(mTextColor);  
            mPaint.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 (mTextBound.width() > mWidth)  
            {  
                TextPaint paint = new TextPaint(mPaint);  
                String msg = TextUtils.ellipsize(mTitle, paint, (float) mWidth - getPaddingLeft() - getPaddingRight(),  
                        TextUtils.TruncateAt.END).toString();  
                canvas.drawText(msg, getPaddingLeft(), mHeight - getPaddingBottom(), mPaint);  

            } else  
            {  
                //正常情况，将字体居中  
                canvas.drawText(mTitle, mWidth / 2 - mTextBound.width() * 1.0f / 2, mHeight - getPaddingBottom(), mPaint);  
            }  

            //取消使用掉的快  
            rect.bottom -= mTextBound.height();  

            if (mImageScale == IMAGE_SCALE_FITXY)  
            {  
                canvas.drawBitmap(mImage, null, rect, mPaint);  
            } else  
            {  
                //计算居中的矩形范围  
                rect.left = mWidth / 2 - mImage.getWidth() / 2;  
                rect.right = mWidth / 2 + mImage.getWidth() / 2;  
                rect.top = (mHeight - mTextBound.height()) / 2 - mImage.getHeight() / 2;  
                rect.bottom = (mHeight - mTextBound.height()) / 2 + mImage.getHeight() / 2;  

                canvas.drawBitmap(mImage, null, rect, mPaint);  
            }  

        }