自定義一個圓形ImageView元件

自定義一個圓形圖檔元件，可設定最多兩個寬度不同且顔色不同的圓形邊框。

使用方法，可以代碼，也可以xml檔案，但是要注意在根标簽下注上

xmlns:imagecontrol="http://schemas.android.com/apk/res-auto"

關于這個屬性大家可以在網上查檢視看，這裡就不再多說了，直接上代碼

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
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.widget.ImageView;



/**
 * 圓形ImageView，可設定最多兩個寬度不同且顔色不同的圓形邊框。
 * 
 * 使用方法，可以代碼，也可以xml檔案，但是要注意在跟标簽下注上
 * xmlns:imagecontrol="http://schemas.android.com/apk/res-auto"
 * 
 * <pre>
 * <com.text.myui.RoundImageView
 *         android:id="@+id/roundImage_two_border"
 *         android:layout_width="120dp"
 *         android:layout_height="120dp"
 *         android:scaleType="centerCrop"
 *         imagecontrol:border_inside_color="#fff7f2e9"
 *         imagecontrol:border_outside_color="#ffd5d1c8"
 *         imagecontrol:border_thickness="2dp" 
 *        android:src="@drawable/image_1"/>
 * </pre>
 * 
 */
public class MyRoundImageView extends ImageView {
	private int mBorderThickness = 0;
	private Context mContext;
	private int defaultColor = 0xFFFFFFFF;
	// 如果隻有其中一個有值，則隻畫一個圓形邊框
	private int mBorderOutsideColor = 0;
	private int mBorderInsideColor = 0;
	// 控件預設長、寬
	private int defaultWidth = 0;
	private int defaultHeight = 0;

	public RoundImageView(Context context) {
		super(context);
		mContext = context;
	}

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

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

	@SuppressLint("Recycle")
	private void setCustomAttributes(AttributeSet attrs) {
		TypedArray a = mContext.obtainStyledAttributes(attrs,
				R.styleable.roundedimageview);
		mBorderThickness = a.getDimensionPixelSize(
				R.styleable.roundedimageview_border_thickness, 0);
		mBorderOutsideColor = a
				.getColor(R.styleable.roundedimageview_border_outside_color,
						defaultColor);
		mBorderInsideColor = a.getColor(
				R.styleable.roundedimageview_border_inside_color, defaultColor);
	}

	@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);
		if (defaultWidth == 0) {
			defaultWidth = getWidth();
		}
		if (defaultHeight == 0) {
			defaultHeight = getHeight();
		}
		// 保證重新讀取圖檔後不會因為圖檔大小而改變控件寬、高的大小
		int radius = 0;
		if (mBorderInsideColor != defaultColor
				&& mBorderOutsideColor != defaultColor) {// 定義畫兩個邊框，分别為外圓邊框和内圓邊框
			radius = (defaultWidth < defaultHeight ? defaultWidth
					: defaultHeight) / 2 - 2 * mBorderThickness;
			// 畫内圓
			drawCircleBorder(canvas, radius + mBorderThickness / 2,
					mBorderInsideColor);
			// 畫外圓
			drawCircleBorder(canvas, radius + mBorderThickness
					+ mBorderThickness / 2, mBorderOutsideColor);
		} else if (mBorderInsideColor != defaultColor
				&& mBorderOutsideColor == defaultColor) {// 定義畫一個邊框
			radius = (defaultWidth < defaultHeight ? defaultWidth
					: defaultHeight) / 2 - mBorderThickness;
			drawCircleBorder(canvas, radius + mBorderThickness / 2,
					mBorderInsideColor);
		} else if (mBorderInsideColor == defaultColor
				&& mBorderOutsideColor != defaultColor) {// 定義畫一個邊框
			radius = (defaultWidth < defaultHeight ? defaultWidth
					: defaultHeight) / 2 - mBorderThickness;
			drawCircleBorder(canvas, radius + mBorderThickness / 2,
					mBorderOutsideColor);
		} else {// 沒有邊框
			radius = (defaultWidth < defaultHeight ? defaultWidth
					: defaultHeight) / 2;
		}
		Bitmap roundBitmap = getCroppedRoundBitmap(bitmap, radius);
		canvas.drawBitmap(roundBitmap, defaultWidth / 2 - radius, defaultHeight
				/ 2 - radius, null);
	}

	/**
	 * 擷取裁剪後的圓形圖檔
	 * 
	 * @param radius
	 *            半徑
	 */
	public Bitmap getCroppedRoundBitmap(Bitmap bmp, int radius) {
		Bitmap scaledSrcBmp;
		int diameter = radius * 2;
		// 為了防止寬高不相等，造成圓形圖檔變形，是以截取長方形中處于中間位置最大的正方形圖檔
		int bmpWidth = bmp.getWidth();
		int bmpHeight = bmp.getHeight();
		int squareWidth = 0, squareHeight = 0;
		int x = 0, y = 0;
		Bitmap squareBitmap;
		if (bmpHeight > bmpWidth) {// 高大于寬
			squareWidth = squareHeight = bmpWidth;
			x = 0;
			y = (bmpHeight - bmpWidth) / 2;
			// 截取正方形圖檔
			squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
					squareHeight);
		} else if (bmpHeight < bmpWidth) {// 寬大于高
			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(), 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 = null;
		squareBitmap = null;
		scaledSrcBmp = null;
		return output;
	}

	/**
	 * 邊緣畫圓
	 */
	private void drawCircleBorder(Canvas canvas, int radius, int color) {
		Paint paint = new Paint();
		/* 去鋸齒 */
		paint.setAntiAlias(true);
		paint.setFilterBitmap(true);
		paint.setDither(true);
		paint.setColor(color);
		/* 設定paint的　style　為STROKE：空心 */
		paint.setStyle(Paint.Style.STROKE);
		/* 設定paint的外框寬度 */
		paint.setStrokeWidth(mBorderThickness);
		canvas.drawCircle(defaultWidth / 2, defaultHeight / 2, radius, paint);
	}  
}
           

寫完後大家可以在Palette的custom中找到，大家可以直接複制代碼試試