自定义圆形ImageView控件的两种方法

这样摘录的目的在于，学习自定义控件的时候可以对比着看看同一种效果不同的写法有什么差异

第一种，写在自己项目中的自定义圆形Imageview

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;

public class CircleImageView extends ImageView {

	private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP;

	private static final Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888;
	private static final int COLORDRAWABLE_DIMENSION = 1;

	private static final int DEFAULT_BORDER_WIDTH = 2;
	private static final int DEFAULT_BORDER_COLOR = Color.WHITE;

	private final RectF mDrawableRect = new RectF();
	private final RectF mBorderRect = new RectF();

	private final Matrix mShaderMatrix = new Matrix();
	private final Paint mBitmapPaint = new Paint();
	private final Paint mBorderPaint = new Paint();

	private int mBorderColor = DEFAULT_BORDER_COLOR;
	private int mBorderWidth = DEFAULT_BORDER_WIDTH;

	private Bitmap mBitmap;
	private BitmapShader mBitmapShader;
	private int mBitmapWidth;
	private int mBitmapHeight;

	private float mDrawableRadius;
	private float mBorderRadius;

	private boolean mReady;
	private boolean mSetupPending;

	public CircleImageView(Context context) {
		super(context);
	}

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

	public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		super.setScaleType(SCALE_TYPE);

		mReady = true;

		if (mSetupPending) {
			setup();
			mSetupPending = false;
		}
	}

	@Override
	public ScaleType getScaleType() {
		return SCALE_TYPE;
	}

	@Override
	public void setScaleType(ScaleType scaleType) {
		if (scaleType != SCALE_TYPE) {
			throw new IllegalArgumentException(String.format("ScaleType %s not supported.", scaleType));
		}
	}

	@Override
	protected void onDraw(Canvas canvas) {
		if (getDrawable() == null) {
			return;
		}

		canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius, mBitmapPaint);
		canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius, mBorderPaint);
	}

	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh) {
		super.onSizeChanged(w, h, oldw, oldh);
		setup();
	}

	public int getBorderColor() {
		return mBorderColor;
	}

	public void setBorderColor(int borderColor) {
		if (borderColor == mBorderColor) {
			return;
		}

		mBorderColor = borderColor;
		mBorderPaint.setColor(mBorderColor);
		invalidate();
	}

	public int getBorderWidth() {
		return mBorderWidth;
	}

	public void setBorderWidth(int borderWidth) {
		if (borderWidth == mBorderWidth) {
			return;
		}

		mBorderWidth = borderWidth;
		setup();
	}

	@Override
	public void setImageBitmap(Bitmap bm) {
		super.setImageBitmap(bm);
		mBitmap = bm;
		setup();
	}

	@Override
	public void setImageDrawable(Drawable drawable) {
		super.setImageDrawable(drawable);
		mBitmap = getBitmapFromDrawable(drawable);
		setup();
	}

	@Override
	public void setImageResource(int resId) {
		super.setImageResource(resId);
		mBitmap = getBitmapFromDrawable(getDrawable());
		setup();
	}

	private Bitmap getBitmapFromDrawable(Drawable drawable) {
		if (drawable == null) {
			return null;
		}

		if (drawable instanceof BitmapDrawable) {
			return ((BitmapDrawable) drawable).getBitmap();
		}

		try {
			Bitmap bitmap;

			if (drawable instanceof ColorDrawable) {
				bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION, COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);
			} else {
				bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), BITMAP_CONFIG);
			}

			Canvas canvas = new Canvas(bitmap);
			drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
			drawable.draw(canvas);
			return bitmap;
		} catch (OutOfMemoryError e) {
			return null;
		}
	}

	private void setup() {
		if (!mReady) {
			mSetupPending = true;
			return;
		}

		if (mBitmap == null) {
			return;
		}

		mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

		mBitmapPaint.setAntiAlias(true);
		mBitmapPaint.setShader(mBitmapShader);

		mBorderPaint.setStyle(Paint.Style.STROKE);
		mBorderPaint.setAntiAlias(true);
		mBorderPaint.setColor(mBorderColor);
		mBorderPaint.setStrokeWidth(mBorderWidth);

		mBitmapHeight = mBitmap.getHeight();
		mBitmapWidth = mBitmap.getWidth();

		mBorderRect.set(0, 0, getWidth(), getHeight());
		mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2, (mBorderRect.width() - mBorderWidth) / 2);

		mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width() - mBorderWidth, mBorderRect.height() - mBorderWidth);
		mDrawableRadius = Math.min(mDrawableRect.height() / 2, mDrawableRect.width() / 2);

		updateShaderMatrix();
		invalidate();
	}

	private void updateShaderMatrix() {
		float scale;
		float dx = 0;
		float dy = 0;

		mShaderMatrix.set(null);

		if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width() * mBitmapHeight) {
			scale = mDrawableRect.height() / (float) mBitmapHeight;
			dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
		} else {
			scale = mDrawableRect.width() / (float) mBitmapWidth;
			dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
		}

		mShaderMatrix.setScale(scale, scale);
		mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth, (int) (dy + 0.5f) + mBorderWidth);

		mBitmapShader.setLocalMatrix(mShaderMatrix);
	}

}

第二种  来自于网上  http://blog.csdn.net/feiduclear_up/article/details/46126003  

最后贴出所有代码

package com.xjp.customview;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.NinePatchDrawable;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;

/**
 * Description:圆形ImageView，可设置最多两个宽度不同且颜色不同的圆形边框。
 * User: xjp
 * Date: 2015/5/28
 * Time: 16:24
 */

public class RoundImageView extends ImageView {

    private static final String TAG = "RoundImageView";
    private static final boolean DEBUG = true;
    private int mBorderThickness = 0;
    private Context mContext;
    private int defaultColor = 0xFFFFFFFF;
    // 如果只有其中一个有值，则只画一个圆形边框
    private int mBorderOutsideColor = 0;
    private int mBorderInsideColor = 0;
    // 控件默认长、宽
    private int defaultWidth = 0;
    private int defaultHeight = 0;
    //控件画圆的宽高。
    private int requestWH = 0;

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

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

    public RoundImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mContext = context;
        setCustomAttributes(attrs);
    }

    /**
     * 获得自定义控件属性值
     *
     * @param attrs
     */
    private void setCustomAttributes(AttributeSet attrs) {
        TypedArray a = mContext.obtainStyledAttributes(attrs,
                R.styleable.RoundImageView);
        mBorderThickness = a.getDimensionPixelSize(
                R.styleable.RoundImageView_border_thickness, 0);
        mBorderOutsideColor = a
                .getColor(R.styleable.RoundImageView_border_outside_color,
                        defaultColor);
        mBorderInsideColor = a.getColor(
                R.styleable.RoundImageView_border_inside_color, defaultColor);
        a.recycle();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Drawable drawable = getDrawable();
        if (drawable == null) {
            return;
        }

        if (getWidth() == 0 || getHeight() == 0) {
            return;
        }
        this.measure(0, 0);
        if (drawable.getClass() == NinePatchDrawable.class) {
            return;
        }
        Bitmap b = ((BitmapDrawable) drawable).getBitmap();
        Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

        int radius = getRadius(canvas);

        Bitmap roundBitmap = getCroppedRoundBitmap(bitmap, radius);
        canvas.drawBitmap(roundBitmap, requestWH / 2 - radius, requestWH
                / 2 - radius, null);
    }

    /**
     * 获取画园的半径，并且绘制圆的外边框
     *
     * @param canvas
     * @return
     */
    private int getRadius(Canvas canvas) {
        if (defaultWidth == 0) {
            defaultWidth = getWidth();

        }
        if (defaultHeight == 0) {
            defaultHeight = getHeight();
        }
        requestWH = defaultHeight > defaultWidth ? defaultWidth : defaultHeight;

        int radius = 0;
        if (mBorderInsideColor != defaultColor
                && mBorderOutsideColor != defaultColor) {// 定义画两个边框，分别为外圆边框和内圆边框
            radius = requestWH / 2 - 2 * mBorderThickness;
            // 画内圆
            drawCircleBorder(canvas, radius + mBorderThickness / 2,
                    mBorderInsideColor);
            // 画外圆
            drawCircleBorder(canvas, radius + mBorderThickness
                    + mBorderThickness / 2, mBorderOutsideColor);
        } else if (mBorderInsideColor != defaultColor
                && mBorderOutsideColor == defaultColor) {// 定义画一个边框
            radius = requestWH / 2 - mBorderThickness;
            drawCircleBorder(canvas, radius + mBorderThickness / 2,
                    mBorderInsideColor);
        } else if (mBorderInsideColor == defaultColor
                && mBorderOutsideColor != defaultColor) {// 定义画一个边框
            radius = (defaultWidth < defaultHeight ? defaultWidth
                    : defaultHeight) / 2 - mBorderThickness;
            drawCircleBorder(canvas, radius + mBorderThickness / 2,
                    mBorderOutsideColor);
        } else {// 没有边框
            radius = requestWH / 2;
        }
        return radius;
    }

    /**
     * 获取裁剪后的圆形图片
     *
     * @param radius 半径
     */
    private static Bitmap getCroppedRoundBitmap(Bitmap bmp, int radius) {
        Bitmap scaledSrcBmp;
        int diameter = radius * 2;

        // 为了防止宽高不相等，造成圆形图片变形，因此截取长方形中处于中间位置最大的正方形图片
        int bmpWidth = bmp.getWidth();
        int bmpHeight = bmp.getHeight();
        int squareWidth = 0, squareHeight = 0;
        int x = 0, y = 0;
        Bitmap squareBitmap;
        if (DEBUG) {
            Log.d(TAG, "the Bitmap w:" + bmpWidth + " the Bitmap h:" + bmpHeight);
        }

        if (bmpHeight > bmpWidth) {// 高大于宽
            squareWidth = squareHeight = bmpWidth;
            x = 0;
            y = (bmpHeight - bmpWidth) / 2;
            // 截取正方形图片
            squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
                    squareHeight);
        } else if (bmpHeight < bmpWidth) {// 宽大于高
            squareWidth = squareHeight = bmpHeight;
            x = (bmpWidth - bmpHeight) / 2;
            y = 0;
            squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
                    squareHeight);
        } else {
            squareBitmap = bmp;
        }

        if (squareBitmap.getWidth() != diameter
                || squareBitmap.getHeight() != diameter) {
            scaledSrcBmp = Bitmap.createScaledBitmap(squareBitmap, diameter,
                    diameter, true);

        } else {
            scaledSrcBmp = squareBitmap;
        }
        Bitmap output = Bitmap.createBitmap(scaledSrcBmp.getWidth(),
                scaledSrcBmp.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        Paint paint = new Paint();
        Rect rect = new Rect(0, 0, scaledSrcBmp.getWidth(),
                scaledSrcBmp.getHeight());

        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        canvas.drawARGB(0, 0, 0, 0);
        canvas.drawCircle(scaledSrcBmp.getWidth() / 2,
                scaledSrcBmp.getHeight() / 2, scaledSrcBmp.getWidth() / 2,
                paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(scaledSrcBmp, rect, rect, paint);
        bmp.recycle();
        squareBitmap.recycle();
        scaledSrcBmp.recycle();
        bmp = null;
        squareBitmap = null;
        scaledSrcBmp = null;
        return output;
    }

    /**
     * 边缘画圆
     */
    private void drawCircleBorder(Canvas canvas, int radius, int color) {
        Paint paint = new Paint();
        /* 去锯齿 */
        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        paint.setColor(color);
        /* 设置paint的　style　为STROKE：空心 */
        paint.setStyle(Paint.Style.STROKE);
        /* 设置paint的外框宽度 */
        paint.setStrokeWidth(mBorderThickness);
        canvas.drawCircle(requestWH / 2, requestWH / 2, radius, paint);
    }

    /**
     * 设置外边框的宽度
     *
     * @param borderWith
     */
    public void setBorderWith(int borderWith) {
        mBorderThickness = borderWith;
    }

    /**
     * 设置外边框的颜色
     *
     * @param outsideColor
     */
    public void setBorderOutsideColor(int outsideColor) {
        mBorderOutsideColor = outsideColor;
    }

    /**
     * 设置内边框的颜色
     *
     * @param insideColor
     */
    public void setBorderInsideColor(int insideColor) {
        mBorderInsideColor = insideColor;
    }

}

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4.在布局中这么使用

"http://schemas.android.com/apk/res/android"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    "@+id/myCustom"
        android:layout_width="110dp"
        android:layout_height="110dp"
        android:scaleType="fitCenter"
        android:src="@drawable/image"
        custom:border_inside_color="#ff0000"
        custom:border_outside_color="@android:color/black"
        custom:border_thickness="2dp" />