Android实现圆形图片

废话不多说，先上效果图：

布局文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:define="http://schemas.android.com/apk/res/com.example.circleview"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="@color/dark"    tools:context=".MainActivity" >    <com.example.circleview.CircleImageView        android:layout_height="160dp"        android:layout_width="160dp"        android:layout_centerInParent="true"        android:src="@drawable/beautiful"        define:border_width="2dp"        define:border_color="@color/middlered"/></RelativeLayout>

这个com.example.circleview.CircleImageView 就是一个自定义控件了

实现方式 JAVA代码

package com.example.circleview;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Bitmap;import android.graphics.BitmapShader;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Matrix;import android.graphics.Paint;import android.graphics.RectF;import android.graphics.Shader;import android.graphics.drawable.BitmapDrawable;import android.graphics.drawable.ColorDrawable;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.widget.ImageView;public class CircleImageView extends ImageView {/** * 图片尺寸及质量 */private static final int COLORDRAWABLE_DIMENSION = 1;private static final Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888;/** * 圆形图片填充类型 */private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP;/** * 默认边框的大小和颜色 */private static final int DEFAULT_BORDER_WIDTH = 0;private static final int DEFAULT_BORDER_COLOR = Color.WHITE;/** * 实际边框的大小和颜色 */private int mBorderWidth;private int mBorderColor;/** * 图片渲染方式 */private BitmapShader mBitmapShader;private Paint mBitmapPaint = new Paint();private Paint mBorderPaint = new Paint();/** * 要绘制的图片以及自身宽高 */private Bitmap mBitmap;private int mBitmapHeight;private int mBitmapWidth;private RectF mBorderRect = new RectF();private float mBorderRadius;private RectF mDrawableRect = new RectF();private float mDrawableRadius;private Matrix mShaderMatrix = new Matrix();private boolean mReady;private boolean mSetupPending;public CircleImageView(Context context) {super(context);}public CircleImageView(Context context, AttributeSet attrs) {this(context, attrs, 0);}public CircleImageView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);super.setScaleType(SCALE_TYPE);TypedArray arr = context.obtainStyledAttributes(attrs,R.styleable.CircleImageView, defStyle, 0);mBorderWidth = arr.getDimensionPixelSize(R.styleable.CircleImageView_border_width, DEFAULT_BORDER_WIDTH);mBorderColor = arr.getColor(R.styleable.CircleImageView_border_color,DEFAULT_BORDER_COLOR);arr.recycle();mReady = true;if (mSetupPending) {setup();mSetupPending = false;}}@Overridepublic ScaleType getScaleType() {return SCALE_TYPE;}@Overridepublic void setScaleType(ScaleType scaleType) {if (scaleType != SCALE_TYPE) {throw new IllegalArgumentException(String.format("ScaleType %s not supported.", scaleType));}}@Overrideprotected void onDraw(Canvas canvas) {if (getDrawable() == null) {return;}canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius,mBitmapPaint);canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius,mBorderPaint);}@Overrideprotected void onSizeChanged(int w, int h, int oldw, int oldh) {super.onSizeChanged(w, h, oldw, oldh);setup();}@Overridepublic void setImageBitmap(Bitmap bm) {super.setImageBitmap(bm);mBitmap = bm;setup();}@Overridepublic void setImageDrawable(Drawable drawable) {super.setImageDrawable(drawable);mBitmap = getBitmapFromDrawable(drawable);setup();}@Overridepublic void setImageResource(int resId) {super.setImageResource(resId);mBitmap = getBitmapFromDrawable(getDrawable());setup();}private Bitmap getBitmapFromDrawable(Drawable drawable) {if (drawable == null) {return null;}if (drawable instanceof BitmapDrawable) {return ((BitmapDrawable) drawable).getBitmap();}try {Bitmap bitmap;if (drawable instanceof ColorDrawable) {bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION,COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);} else {bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight(), BITMAP_CONFIG);}Canvas canvas = new Canvas(bitmap);drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());drawable.draw(canvas);return bitmap;} catch (OutOfMemoryError e) {return null;}}public void setBorderColor(int borderColor) {if (borderColor == mBorderColor) {return;}mBorderColor = borderColor;mBorderPaint.setColor(mBorderColor);invalidate();}public int getBorderWidth() {return mBorderWidth;}public void setBorderWidth(int borderWidth) {if (borderWidth == mBorderWidth) {return;}mBorderWidth = borderWidth;setup();}private void setup() {if (!mReady) {mSetupPending = true;return;}if (mBitmap == null) {return;}mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP,Shader.TileMode.CLAMP);mBitmapPaint.setAntiAlias(true); // 是否有锯齿mBitmapPaint.setShader(mBitmapShader);mBitmapHeight = mBitmap.getHeight();mBitmapWidth = mBitmap.getWidth();mBorderPaint.setStyle(Paint.Style.STROKE);mBorderPaint.setAntiAlias(true);mBorderPaint.setColor(mBorderColor);mBorderPaint.setStrokeWidth(mBorderWidth);mBorderRect.set(0, 0, getWidth(), getHeight());mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2,(mBorderRect.width() - mBorderWidth) / 2);mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width()- mBorderWidth, mBorderRect.height() - mBorderWidth);mDrawableRadius = Math.min(mDrawableRect.height() / 2,mDrawableRect.width() / 2);updateShaderMatrix();invalidate();}private void updateShaderMatrix() {float scale;float dx = 0;float dy = 0;mShaderMatrix.set(null);if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width()* mBitmapHeight) {scale = mDrawableRect.height() / (float) mBitmapHeight;dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;} else {scale = mDrawableRect.width() / (float) mBitmapWidth;dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;}mShaderMatrix.setScale(scale, scale);mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth,(int) (dy + 0.5f) + mBorderWidth);mBitmapShader.setLocalMatrix(mShaderMatrix);}}

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