Android实现圆形的图片边角

ImageView没有边角圆化的设置，但是可以通过代码设置实现。一个国外的码农写的方法。

效果：

地址：http://www.curious-creature.org/2012

代码：

 

package com.example.roundrectshader;



import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.view.ViewGroup.LayoutParams;

import android.widget.ArrayAdapter;

import android.widget.ListView;

import android.widget.TextView;

import android.app.Activity;

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.BitmapShader;

import android.graphics.Canvas;

import android.graphics.ColorFilter;

import android.graphics.ComposeShader;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.graphics.PixelFormat;

import android.graphics.PorterDuff;

import android.graphics.RadialGradient;

import android.graphics.Rect;

import android.graphics.RectF;

import android.graphics.Shader;

import android.graphics.drawable.Drawable;



public class StreamActivity extends Activity {

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);



		setContentView(R.layout.activity_stream);



		StreamAdapter adapter = new StreamAdapter(this);

		((ListView) findViewById(R.id.main_list)).setAdapter(adapter);



		adapter.add(new StreamItem(this, R.drawable.photo1, "Tufa at night", "Mono Lake, CA"));

		adapter.add(new StreamItem(this, R.drawable.photo2, "Starry night", "Lake Powell, AZ"));

		adapter.add(new StreamItem(this, R.drawable.photo3, "Racetrack playa", "Death Valley, CA"));

		adapter.add(new StreamItem(this, R.drawable.photo4, "Napali coast", "Kauai, HI"));

		adapter.add(new StreamItem(this, R.drawable.photo5, "Delicate Arch", "Arches, UT"));

		adapter.add(new StreamItem(this, R.drawable.photo6, "Sierra sunset", "Lone Pine, CA"));

		adapter.add(new StreamItem(this, R.drawable.photo7, "Majestic", "Grand Teton, WY"));

	}



	class StreamItem {

		final Bitmap mBitmap;

		final String mLine1;

		final String mLine2;



		StreamItem(Context c, int resid, String line1, String line2) {

			mBitmap = BitmapFactory.decodeResource(c.getResources(), resid);

			mLine1 = line1;

			mLine2 = line2;

		}

	}



	class StreamDrawable extends Drawable {

		private static final boolean USE_VIGNETTE = true;



		private final float mCornerRadius;

		private final RectF mRect = new RectF();

		private final BitmapShader mBitmapShader;

		private final Paint mPaint;

		private final int mMargin;



		StreamDrawable(Bitmap bitmap, float cornerRadius, int margin) {

			mCornerRadius = cornerRadius;



			mBitmapShader = new BitmapShader(bitmap,

					Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);



			mPaint = new Paint();

			mPaint.setAntiAlias(true);

			mPaint.setShader(mBitmapShader);



			mMargin = margin;

		}



		@Override

		protected void onBoundsChange(Rect bounds) {

			super.onBoundsChange(bounds);

			mRect.set(mMargin, mMargin, bounds.width() - mMargin, bounds.height() - mMargin);



			if (USE_VIGNETTE) {

				RadialGradient vignette = new RadialGradient(

						mRect.centerX(), mRect.centerY() * 1.0f / 0.7f, mRect.centerX() * 1.3f,

						new int[] { 0, 0, 0x7f000000 }, new float[] { 0.0f, 0.7f, 1.0f },

						Shader.TileMode.CLAMP);

	

				Matrix oval = new Matrix();

				oval.setScale(1.0f, 0.7f);

				vignette.setLocalMatrix(oval);

	

				mPaint.setShader(

						new ComposeShader(mBitmapShader, vignette, PorterDuff.Mode.SRC_OVER));

			}

		}



		@Override

		public void draw(Canvas canvas) {

			canvas.drawRoundRect(mRect, mCornerRadius, mCornerRadius, mPaint);

		}



		@Override

		public int getOpacity() {

			return PixelFormat.TRANSLUCENT;

		}



		@Override

		public void setAlpha(int alpha) {

			mPaint.setAlpha(alpha);

		}



		@Override

		public void setColorFilter(ColorFilter cf) {

			mPaint.setColorFilter(cf);

		}		

	}





	class StreamAdapter extends ArrayAdapter<StreamItem> {

		private static final int CORNER_RADIUS = 24; // dips

		private static final int MARGIN = 12; // dips



		private final int mCornerRadius;

		private final int mMargin;

		private final LayoutInflater mInflater;



		public StreamAdapter(Context context) {

			super(context, 0);

			

			final float density = context.getResources().getDisplayMetrics().density;

			mCornerRadius = (int) (CORNER_RADIUS * density + 0.5f);

			mMargin = (int) (MARGIN * density + 0.5f);



			mInflater = LayoutInflater.from(getContext());

		}



		@Override

		public View getView(int position, View convertView, ViewGroup parent) {

			ViewGroup view = null;

			

			if (convertView == null) {

				view = (ViewGroup) mInflater.inflate(R.layout.stream_item, parent, false);

			} else {

				view = (ViewGroup) convertView;

			}



			StreamItem item = getItem(position);



			StreamDrawable d = new StreamDrawable(item.mBitmap, mCornerRadius, mMargin);

			view.setBackgroundDrawable(d);



			((TextView) view.findViewById(R.id.textView1)).setText(item.mLine1);

			((TextView) view.findViewById(R.id.textView2)).setText(item.mLine2);



			int w = item.mBitmap.getWidth();

			int h = item.mBitmap.getHeight();



			float ratio = w / (float) h;



			LayoutParams lp = view.getLayoutParams();

			lp.width = getContext().getResources().getDisplayMetrics().widthPixels;

			lp.height = (int) (lp.width / ratio);



			return view;

		}

	}

}