Android Glide 加载圆形图片和圆角图片的两种方法

两种使用 BitmapTransformation 来实现 Glide 加载圆形图片和圆角图片的方法。

背景

Glide 并不能直接支持 Round Pictures ，需要使用 BitmapTransformation 来进行处理。

Round Pictures: CircleImageView / CircularImageView / RoundedImageView are known to haveissues with TransitionDrawable (.crossFade() with .thumbnail() or .placeholder()) and animated GIFs, use a BitmapTransformation (.circleCrop() will be available in v4) or .dontAnimate() to fix the issue.

这里介绍下网上常见的方式和使用 RoundedBitmapDrawable 两种方法，本质上是差不多的：

• 使用 Canvas 和 Paint 来绘制
• 使用 Android.support.v4.graphics.drawable.RoundedBitmapDrawable

PS： RoundedBitmapDrawable 是 support.v4 下的一个类，想了解更多，可以阅读我之前的文章： Android 必知必会-使用 supportV4 的 RoundedBitmapDrawable 实现圆角 。

代码实现

方法一

实现圆形图片：

/** * Glide 圆形图片 Transform */public class GlideCircleTransform extends BitmapTransformation {    public GlideCircleTransform(Context context) {        super(context);    }    @Override    protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {        return circleCrop(pool, toTransform);    }    private static Bitmap circleCrop(BitmapPool pool, Bitmap source) {        if (source == null) return null;        int size = Math.min(source.getWidth(), source.getHeight());        int x = (source.getWidth() - size) / 2;        int y = (source.getHeight() - size) / 2;        Bitmap squared = Bitmap.createBitmap(source, x, y, size, size);        Bitmap result = pool.get(size, size, Bitmap.Config.ARGB_8888);        if (result == null) {            result = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);        }        Canvas canvas = new Canvas(result);        Paint paint = new Paint();        paint.setShader(new BitmapShader(squared, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));        paint.setAntiAlias(true);        float r = size / 2f;        canvas.drawCircle(r, r, r, paint);        return result;    }    @Override    public String getId() {        return getClass().getName();    }}

实现圆角图片：

/** * Glide 圆角 Transform */public class GlideRoundTransform extends BitmapTransformation {    private static float radius = 0f;    /** * 构造函数 默认圆角半径 4dp * * @param context Context */    public GlideRoundTransform(Context context) {        this(context, 4);    }    /** * 构造函数 * * @param context Context * @param dp 圆角半径 */    public GlideRoundTransform(Context context, int dp) {        super(context);        radius = Resources.getSystem().getDisplayMetrics().density * dp;    }    @Override    protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {        return roundCrop(pool, toTransform);    }    private static Bitmap roundCrop(BitmapPool pool, Bitmap source) {        if (source == null) return null;        Bitmap result = pool.get(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);        if (result == null) {            result = Bitmap.createBitmap(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);        }        Canvas canvas = new Canvas(result);        Paint paint = new Paint();        paint.setShader(new BitmapShader(source, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));        paint.setAntiAlias(true);        RectF rectF = new RectF(0f, 0f, source.getWidth(), source.getHeight());        canvas.drawRoundRect(rectF, radius, radius, paint);        return result;    }    @Override    public String getId() {        return getClass().getName() + Math.round(radius);    }}

方法二

public static Bitmap drawableToBitmap(Drawable drawable) {        // 取 drawable 的长宽        int w = drawable.getIntrinsicWidth();        int h = drawable.getIntrinsicHeight();        // 取 drawable 的颜色格式        Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888                : Bitmap.Config.RGB_565;        // 建立对应 bitmap        Bitmap bitmap = Bitmap.createBitmap(w, h, config);        // 建立对应 bitmap 的画布        Canvas canvas = new Canvas(bitmap);        drawable.setBounds(0, 0, w, h);        // 把 drawable 内容画到画布中        drawable.draw(canvas);        return bitmap;    }/** * RoundedBitmapDrawable 是 V4 下的一个类，不能简单的通过：强制转换成 BitmapDrawable * Bitmap bitmap = ((BitmapDrawable)xxx).getBitmap(); */

实现圆形：

RoundedBitmapDrawable drawableA = RoundedBitmapDrawableFactory.create(getResources(), bitmap);        drawableA.setCircular(true);        Bitmap a = drawableToBitmap(drawableA);

实现圆角：

RoundedBitmapDrawable drawableB = RoundedBitmapDrawableFactory.create(getResources(), bitmap);       drawableB.setCornerRadius(30L);       Bitmap b = drawableToBitmap(drawableB);

 

来自：http://likfe.com/2016/08/31/android-glide-roundedBitmapTransformation/