Selectable circular imageview like Google+

问题

How can I create a selectable circular ImageView like in the current Google+ app used for the profile pictures?

This is what I refer to:

The image above is unselected and the below is selected.

I try to replicate the profile pictures 1 to 1.

My work so far:

loadedImage is the Bitmap which is displayed

mImageView.setBackground(createStateListDrawable());
mImageView.setImageBitmap(createRoundImage(loadedImage));

The used methods:

private Bitmap createRoundImage(Bitmap loadedImage) {
    Bitmap circleBitmap = Bitmap.createBitmap(loadedImage.getWidth(), loadedImage.getHeight(), Bitmap.Config.ARGB_8888);

    BitmapShader shader = new BitmapShader(loadedImage, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
    Paint paint = new Paint();
    paint.setAntiAlias(true);
    paint.setShader(shader);

    Canvas c = new Canvas(circleBitmap);
    c.drawCircle(loadedImage.getWidth() / 2, loadedImage.getHeight() / 2, loadedImage.getWidth() / 2, paint);

    return circleBitmap;
}

private StateListDrawable createStateListDrawable() {
    StateListDrawable stateListDrawable = new StateListDrawable();

    OvalShape ovalShape = new OvalShape();
    ShapeDrawable shapeDrawable = new ShapeDrawable(ovalShape);
    stateListDrawable.addState(new int[] { android.R.attr.state_pressed }, shapeDrawable);
    stateListDrawable.addState(StateSet.WILD_CARD, shapeDrawable);

    return stateListDrawable;
}

The size of the ImageView is imageSizePx and the size of the image is imageSizePx - 3. So, that means the background should overlap the image. Which doesn't work.

回答1:

Really simple solution, thanks to @CommonsWare for the tips.

Size of Bitmap: imageSizePx - 3DP
Size of ImageView: imageSizePx

mImageView.setBackground(createStateListDrawable(imageSizePx));
mImageView.setImageBitmap(loadedImage);

private StateListDrawable createStateListDrawable(int size) {
    StateListDrawable stateListDrawable = new StateListDrawable();

    OvalShape ovalShape = new OvalShape();
    ovalShape.resize(size, size);
    ShapeDrawable shapeDrawable = new ShapeDrawable(ovalShape);
    shapeDrawable.getPaint().setColor(getResources().getColor(R.color.somecolor));

    stateListDrawable.addState(new int[]{android.R.attr.state_pressed}, shapeDrawable);
    stateListDrawable.addState(new int[]{android.R.attr.state_focused}, shapeDrawable);
    stateListDrawable.addState(new int[]{}, null);

    return stateListDrawable;
}

回答2:

Assuming that by "selectable" you mean "checkable, like a CheckBox", then that could be some CompoundButton that is using a StateListDrawable with regular and checked states for the background behind the "SkillOverflow" foreground image.

You can use uiautomatorviewer to see what the actual widget is that Google+ uses.

回答3:

You can make a custom View that extends ImageView. Override onDraw to clip the canvas with a circular region and draw the image on the canvas. Something like this as a starting point:

public class CircularImageView extends ImageView {
    /* constructors omitted for brevity ... */

    protected void onDraw(Canvas canvas) {
        int saveCount = canvas.save();

        // clip in a circle

        // draw image
        Drawable d = getDrawable();
        if (d != null) {
            d.draw(canvas);
        }

        // do extra drawing on canvas if pressed

        canvas.restoreToCount(saveCount);
    }
}

Take some time to get familiar with the Canvas and other 2D drawing APIs in Android.

回答4:

I was able to achieve this effect through a custom ImageView by overriding onDraw and painting some sort of "border" whenever it detects a touch event. As a bonus, there is a selector overlay. Hopefully you may find this view helpful...

https://github.com/Pkmmte/CircularImageView

回答5:

https://github.com/hdodenhof/CircleImageView

Best library so far, super easy to integrate. It will give you border width and color option, you can change the color onClick to match your query.

来源：https://stackoverflow.com/questions/16922732/selectable-circular-imageview-like-google

标签

android

graphics

imageview