Glide 设置了CenterCrop属性和圆角图像冲突

自定义了一个ImageView用于展示圆角图片：

public class RoundCornerImageView extends android.support.v7.widget.AppCompatImageView {

    private int mRadius;

    public RoundCornerImageView(Context context) {
        super(context);
        init(context, null);
    }

    public RoundCornerImageView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs);
    }

    public RoundCornerImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context, attrs);
    }

    private void init(Context context, AttributeSet attrs) {
        if (attrs != null) {
            TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.RoundCornerImageView);
            try {
                boolean hasRadius = typedArray.hasValue(R.styleable.RoundCornerImageView_roundcorner_radius);
                if (hasRadius) {
                    int radius = typedArray.getInt(R.styleable.RoundCornerImageView_roundcorner_radius, 1);
                    mRadius = radius;
                }
            } finally {
                typedArray.recycle();
            }
        }
    }

    public void setImage(String url) {
        GlideRoundTransform glideRoundTransform;
        if (mRadius == 0) {
            glideRoundTransform = new GlideRoundTransform(getContext());
        } else {
            glideRoundTransform = new GlideRoundTransform(getContext(), mRadius);
        }
        Glide.with(TPApplication.getAppContext())
                .load(url)
                .centerCrop()
                .transform(glideRoundTransform)
                .placeholder(R.drawable.nearby_online_me_photo)
                .diskCacheStrategy(DiskCacheStrategy.ALL)
                .dontAnimate()
                .into(this);
    }
}

其中，自定义了一个BitmapTransformation，用于实现圆角，代码为：

public class GlideRoundTransform extends BitmapTransformation {

    private float mRadius = 0f;

    public GlideRoundTransform(Context context) {
        this(context, 4);
    }

    public GlideRoundTransform(Context context, int dp) {
        super(context);
        mRadius = DimentionUtil.dp2px(dp);
    }

    @Override
    protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
        return roundCrop(pool, toTransform);
    }

    @Override
    public String getId() {
        return getClass().getName() + Math.round(mRadius);
    }

    private 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, mRadius, mRadius, paint);
        return result;
    }
}

用这个自定义imageView展示图片是，xml代码为：

这样在java代码中：

private final RoundCornerImageView mAvatar;

mAvatar.setImage(url);

问题是，这样的结果是有些图片没有铺满整个view，说明.centerCrop()失效了。说明transform的设置覆盖了上一句.centerCrop()的作用。

于是我们就在xml中加了scaleType这个属性，即

运行结果显示：部分图片没有了圆角，倒是解决了没有铺满View的问题，但是铺满之后变成正方形了。说明transfom（）没有生效。

分析发现，centerCorp的源码是：

public RequestOptions centerCrop() {  
  return transform(DownsampleStrategy.CENTER_OUTSIDE, new CenterCrop());  
} 

这样的意思就是：

这里面也是继承了BitmapTransformation这个类然后重画了一边，后面我们自己有调用了transform()这个方法等于把系统的Centercrop这个方法给覆盖了，所以说这两个属性谁在后面就用哪种效果。

于是就知道了：用自定义的BitmapTransformation将两个效果一起画出来！

public class GlideRoundTransform extends BitmapTransformation {

    private float mRadius = 0f;

    public GlideRoundTransform(Context context) {
        this(context, 4);
    }

    public GlideRoundTransform(Context context, int dp) {
        super(context);
        mRadius = DimentionUtil.dp2px(dp);
    }

    @Override
    protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
        final Bitmap toReuse = pool.get(outWidth, outHeight, toTransform.getConfig() != null
                ? toTransform.getConfig() : Bitmap.Config.ARGB_8888);
        Bitmap bitmap = TransformationUtils.centerCrop(toReuse, toTransform, outWidth, outHeight);
        return roundCrop(pool, bitmap);
    }

    @Override
    public String getId() {
        return getClass().getName() + Math.round(mRadius);
    }

    private 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, mRadius, mRadius, paint);
        return result;
    }
}

这样的话，在自定义imageView是使用如下代码：

    public void setImage(String url) {
        GlideRoundTransform glideRoundTransform;
        if (mRadius == 0) {
            glideRoundTransform = new GlideRoundTransform(getContext());
        } else {
            glideRoundTransform = new GlideRoundTransform(getContext(), mRadius);
        }
        Glide.with(TPApplication.getAppContext())
                .load(url)
                .transform(glideRoundTransform)
                .placeholder(R.drawable.nearby_online_me_photo)
                .diskCacheStrategy(DiskCacheStrategy.ALL)
                .dontAnimate()
                .into(this);
    }

完美解决问题。