1.新建一个RoundImageView.java文件

package com.jhg.freshman;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;import android.graphics.drawable.Drawable;import android.os.Build;import android.util.AttributeSet;import android.util.TypedValue;import android.widget.ImageView; public class RoundImageView extends android.support.v7.widget.AppCompatImageView { /** * 圆形模式 */ private static final int MODE_CIRCLE = 1; /** * 普通模式 */ private static final int MODE_NONE = 0; /** * 圆角模式 */ private static final int MODE_ROUND = 2; private Paint mPaint; private int currMode = 0; /** * 圆角半径 */ private int currRound = dp2px(10); public RoundImageView(Context context) { super(context); initViews(); } public RoundImageView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public RoundImageView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); obtainStyledAttrs(context, attrs, defStyleAttr); initViews(); } private void obtainStyledAttrs(Context context, AttributeSet attrs, int defStyleAttr) { TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RoundImageView, defStyleAttr, 0); currMode = a.hasValue(R.styleable.RoundImageView_type) ? a.getInt(R.styleable.RoundImageView_type, MODE_NONE) : MODE_NONE; currRound = a.hasValue(R.styleable.RoundImageView_radius) ? a.getDimensionPixelSize(R.styleable.RoundImageView_radius, currRound) : currRound; a.recycle(); } private void initViews() { mPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { /** * 当模式为圆形模式的时候，我们强制让宽高一致 */ if (currMode == MODE_CIRCLE) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int result = Math.min(getMeasuredHeight(), getMeasuredWidth()); setMeasuredDimension(result, result); } else { super.onMeasure(widthMeasureSpec, heightMeasureSpec); } } @Override protected void onDraw(Canvas canvas) { Drawable mDrawable = getDrawable(); Matrix mDrawMatrix = getImageMatrix(); if (mDrawable == null) { return; // couldn't resolve the URI } if (mDrawable.getIntrinsicWidth() == 0 || mDrawable.getIntrinsicHeight() == 0) { return; // nothing to draw (empty bounds) } if (mDrawMatrix == null && getPaddingTop() == 0 && getPaddingLeft() == 0) { mDrawable.draw(canvas); } else { final int saveCount = canvas.getSaveCount(); canvas.save(); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) { if (getCropToPadding()) { final int scrollX = getScrollX(); final int scrollY = getScrollY(); canvas.clipRect(scrollX + getPaddingLeft(), scrollY + getPaddingTop(), scrollX + getRight() - getLeft() - getPaddingRight(), scrollY + getBottom() - getTop() - getPaddingBottom()); } } canvas.translate(getPaddingLeft(), getPaddingTop()); if (currMode == MODE_CIRCLE) {//当为圆形模式的时候 Bitmap bitmap = drawable2Bitmap(mDrawable); mPaint.setShader(new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP)); canvas.drawCircle(getWidth() / 2, getHeight() / 2, getWidth() / 2, mPaint); } else if (currMode == MODE_ROUND) {//当为圆角模式的时候 Bitmap bitmap = drawable2Bitmap(mDrawable); mPaint.setShader(new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP)); canvas.drawRoundRect(new RectF(getPaddingLeft(), getPaddingTop(), getWidth() - getPaddingRight(), getHeight() - getPaddingBottom()), currRound, currRound, mPaint); } else { if (mDrawMatrix != null) { canvas.concat(mDrawMatrix); } mDrawable.draw(canvas); } canvas.restoreToCount(saveCount); } } /** * drawable转换成bitmap */ private Bitmap drawable2Bitmap(Drawable drawable) { if (drawable == null) { return null; } Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); //根据传递的scaletype获取matrix对象，设置给bitmap Matrix matrix = getImageMatrix(); if (matrix != null) { canvas.concat(matrix); } drawable.draw(canvas); return bitmap; } private int dp2px(float value) { return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, value, getResources().getDisplayMetrics()); } }

2.在Value下新建一个attrs.xml文件

<?xml version="1.0" encoding="utf-8"?><resources> <declare-styleable name="RoundImageView"> <attr name="type" format="enum"> <enum name="circle" value="1"/> <enum name="round" value="2"/> </attr> <attr name="radius" format="dimension"/>ssss </declare-styleable></resources>

3.在layout布局文件中使用RoundImage控件

<com.jhg.freshman.RoundImageView android:id="@+id/iv" android:layout_width="70dp" android:layout_height="70dp" android:layout_centerHorizontal="true" android:layout_marginTop="50dp" android:src="@drawable/head" app:type="circle" />