第一步，建一个RoundImageView类，继承ImageView
package com.zhy.view; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.BitmapShader; import android.graphics.Canvas; import android.graphics.Matrix; import android.graphics.Paint; import android.graphics.RectF; import android.graphics.Shader.TileMode; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.Drawable; import android.os.Bundle; import android.os.Parcelable; import android.util.AttributeSet; import android.util.Log; import android.util.TypedValue; import android.widget.ImageView; import activity.chuangdun.com.roundimageview.R; /** * Created by Administrator on 2016/5/20. */ public class RoundImageView extends ImageView { /** * 图片的类型，圆形or圆角 */ private int type; public static final int TYPE_CIRCLE = 0; public static final int TYPE_ROUND = 1; /** * 圆角大小的默认值 */ private static final int BODER_RADIUS_DEFAULT = 10; /** * 圆角的大小 */ private int mBorderRadius; /** * 绘图的Paint */ private Paint mBitmapPaint; /** * 圆角的半径 */ private int mRadius; /** * 3x3 矩阵，主要用于缩小放大 */ private Matrix mMatrix; /** * 渲染图像，使用图像为绘制图形着色 */ private BitmapShader mBitmapShader; /** * view的宽度 */ private int mWidth; private RectF mRoundRect; public RoundImageView(Context context, AttributeSet attrs) { super(context, attrs); mMatrix = new Matrix(); mBitmapPaint = new Paint(); mBitmapPaint.setAntiAlias(true); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RoundImageView); mBorderRadius = a.getDimensionPixelSize( R.styleable.RoundImageView_borderRadius, (int) TypedValue .applyDimension(TypedValue.COMPLEX_UNIT_DIP, BODER_RADIUS_DEFAULT, getResources() .getDisplayMetrics()));// 默认为10dp type = a.getInt(R.styleable.RoundImageView_type, TYPE_CIRCLE);// 默认为Circle a.recycle(); } public RoundImageView(Context context) { this(context, null); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); /** * 如果类型是圆形，则强制改变view的宽高一致，以小值为准 */ if (type == TYPE_CIRCLE) { mWidth = Math.min(getMeasuredWidth(), getMeasuredHeight()); mRadius = mWidth / 2; setMeasuredDimension(mWidth, mWidth); } } /** * 初始化BitmapShader */ private void setUpShader() { Drawable drawable = getDrawable(); if (drawable == null) { return; } Bitmap bmp = drawableToBitamp(drawable); // 将bmp作为着色器，就是在指定区域内绘制bmp mBitmapShader = new BitmapShader(bmp, TileMode.CLAMP, TileMode.CLAMP); float scale = 1.0f; if (type == TYPE_CIRCLE) { // 拿到bitmap宽或高的小值 int bSize = Math.min(bmp.getWidth(), bmp.getHeight()); scale = mWidth * 1.0f / bSize; } else if (type == TYPE_ROUND) { Log.e("TAG", "b'w = " + bmp.getWidth() + " , " + "b'h = " + bmp.getHeight()); if (!(bmp.getWidth() == getWidth() && bmp.getHeight() == getHeight())) { // 如果图片的宽或者高与view的宽高不匹配，计算出需要缩放的比例；缩放后的图片的宽高，一定要大于我们view的宽高；所以我们这里取大值； scale = Math.max(getWidth() * 1.0f / bmp.getWidth(), getHeight() * 1.0f / bmp.getHeight()); } } // shader的变换矩阵，我们这里主要用于放大或者缩小 mMatrix.setScale(scale, scale); // 设置变换矩阵 mBitmapShader.setLocalMatrix(mMatrix); // 设置shader mBitmapPaint.setShader(mBitmapShader); } @Override protected void onDraw(Canvas canvas) { Log.e("TAG", "onDraw"); if (getDrawable() == null) { return; } setUpShader(); if (type == TYPE_ROUND) { canvas.drawRoundRect(mRoundRect, mBorderRadius, mBorderRadius, mBitmapPaint); } else { canvas.drawCircle(mRadius, mRadius, mRadius, mBitmapPaint); // drawSomeThing(canvas); } } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); // 圆角图片的范围 if (type == TYPE_ROUND) mRoundRect = new RectF(0, 0, w, h); } /** * drawable转bitmap * * @param drawable * @return */ private Bitmap drawableToBitamp(Drawable drawable) { if (drawable instanceof BitmapDrawable) { BitmapDrawable bd = (BitmapDrawable) drawable; return bd.getBitmap(); } int w = drawable.getIntrinsicWidth(); int h = drawable.getIntrinsicHeight(); Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); drawable.setBounds(0, 0, w, h); drawable.draw(canvas); return bitmap; } private static final String STATE_INSTANCE = "state_instance"; private static final String STATE_TYPE = "state_type"; private static final String STATE_BORDER_RADIUS = "state_border_radius"; @Override protected Parcelable onSaveInstanceState() { Bundle bundle = new Bundle(); bundle.putParcelable(STATE_INSTANCE, super.onSaveInstanceState()); bundle.putInt(STATE_TYPE, type); bundle.putInt(STATE_BORDER_RADIUS, mBorderRadius); return bundle; } @Override protected void onRestoreInstanceState(Parcelable state) { if (state instanceof Bundle) { Bundle bundle = (Bundle) state; super.onRestoreInstanceState(((Bundle) state) .getParcelable(STATE_INSTANCE)); this.type = bundle.getInt(STATE_TYPE); this.mBorderRadius = bundle.getInt(STATE_BORDER_RADIUS); } else { super.onRestoreInstanceState(state); } } public void setBorderRadius(int borderRadius) { int pxVal = dp2px(borderRadius); if (this.mBorderRadius != pxVal) { this.mBorderRadius = pxVal; invalidate(); } } public void setType(int type) { if (this.type != type) { this.type = type; if (this.type != TYPE_ROUND && this.type != TYPE_CIRCLE) { this.type = TYPE_CIRCLE; } requestLayout(); } } public int dp2px(int dpVal) { return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dpVal, getResources().getDisplayMetrics()); } }
然后再布局文件中引入RoundImageView
<?xml version="1.0" encoding="utf-8"?> <ScrollView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:zhy="http://schemas.android.com/apk/activity.chuangdun.com.roundimageview" android:layout_width="match_parent" android:layout_height="wrap_content" > <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <com.zhy.view.RoundImageView android:layout_width="200dp" android:layout_height="200dp" android:layout_margin="10dp" android:src="@drawable/aa" > </com.zhy.view.RoundImageView> </LinearLayout> </ScrollView>
简单的几步就实现的圆角图片