因此，我通过在应用程序的主布局中向用户显示的各种视图进行动画处理，在应用程序中动态创建图像。
目前，我正在相对布局中生成场景，将布局图像作为位图，然后将位图保存到 SD，以便 appwidget 通过 uri 访问。
这一切都工作得很好，但是......为了尝试为应用程序小部件图像创建圆角，我尝试使用我发现的这两个片段here. https://stackoverflow.com/questions/16161448/how-to-make-layout-with-rounded-corners
我的问题：
是这个方法生成一个可绘制的（如果显示为可绘制的，其圆角看起来很完美），但我需要将这些透明角导出为图像文件。下面 CustomView 中的 drawToBitmap 方法确实生成了位图图像，但角是完整的且方形的。
/**
* shows a bitmap as if it had rounded corners. based on :
* http://rahulswackyworld.blogspot.co.il/2013/04/android-drawables-with-rounded_7.html
*/
public class RoundedCornersDrawable extends BitmapDrawable {
private final BitmapShader bitmapShader;
private final Paint p;
private final RectF rect;
private final float borderRadius;
public RoundedCornersDrawable(final Resources resources, final Bitmap bitmap, final float borderRadius) {
super(resources, bitmap);
bitmapShader = new BitmapShader(getBitmap(), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
final Bitmap b = getBitmap();
p = getPaint();
p.setAntiAlias(true);
p.setShader(bitmapShader);
final int w = b.getWidth(), h = b.getHeight();
rect = new RectF(0, 0, w, h);
this.borderRadius = borderRadius < 0 ? 0.15f * Math.min(w, h) : borderRadius;
}
@Override
public void draw(final Canvas canvas) {
canvas.drawRoundRect(rect, borderRadius, borderRadius, p);
}
}
and
public class CustomView extends ImageView {
private FrameLayout mMainContainer;
private boolean mIsDirty=false;
// TODO for each change of views/content, set mIsDirty to true and call invalidate
@Override
protected void onDraw(final Canvas canvas) {
if (mIsDirty) {
mIsDirty = false;
drawContent();
return;
}
super.onDraw(canvas);
}
/**
* draws the view's content to a bitmap. code based on :
* http://nadavfima.com/android-snippet-inflate-a-layout-draw-to-a-bitmap/
*/
public static Bitmap drawToBitmap(final View viewToDrawFrom, final int width, final int height) {
// Create a new bitmap and a new canvas using that bitmap
final Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
final Canvas canvas = new Canvas(bmp);
viewToDrawFrom.setDrawingCacheEnabled(true);
// Supply measurements
viewToDrawFrom.measure(MeasureSpec.makeMeasureSpec(canvas.getWidth(), MeasureSpec.EXACTLY),
MeasureSpec.makeMeasureSpec(canvas.getHeight(), MeasureSpec.EXACTLY));
// Apply the measures so the layout would resize before drawing.
viewToDrawFrom.layout(0, 0, viewToDrawFrom.getMeasuredWidth(), viewToDrawFrom.getMeasuredHeight());
// and now the bmp object will actually contain the requested layout
canvas.drawBitmap(viewToDrawFrom.getDrawingCache(), 0, 0, new Paint());
return bmp;
}
private void drawContent() {
if (getMeasuredWidth() <= 0 || getMeasuredHeight() <= 0)
return;
final Bitmap bitmap = drawToBitmap(mMainContainer, getMeasuredWidth(), getMeasuredHeight());
final RoundedCornersDrawable drawable = new RoundedCornersDrawable(getResources(), bitmap, 15);
setImageDrawable(drawable);
}
}
据我了解，位图不携带图像中具有透明圆角所需的 alpha 信息，
所以我尝试将文件另存为 PNG 像这样；
RCD_test 是一个 RoundedCornersDrawable
Bitmap bitmap = RCD_test.getBitmap();
bitmap.setHasAlpha(true);
OutputStream stream = new
FileOutputStream(Environment.getExternalStorageDirectory().getPath()+"/test/screenshottest.png");
bitmap.compress(CompressFormat.PNG, 100, stream);
stream.close();
但无济于事。整个方法可能看起来很复杂，但这就是我为解决 AppWidget 的 RemoteViews 的限制而想出的方法。
我的问题：
我如何获取这个 RoundedCornersDrawable，并将其导出为 PNG 文件，以正确描绘其美丽的透明角？
预先感谢您的帮助，我愿意接受关于解决整个问题的不同方法的任何和所有建议！
