一般做社交類APP，包括其他很多隻要有個人頁面的基本都會有設定頭像的這個功能，而且大多數也是圓形的頭像，顯的也比較美觀，github上有很多別人的第三方工具類，今天沒事就自己研究了一下看了看原始碼，下面附上程式碼。

   自定義View

CircleImageView

package com.zero.cui.circleimageview;
import android.annotation.SuppressLint;
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.net.Uri;
import android.util.AttributeSet;
import android.widget.ImageView;
@SuppressLint("AppCompatCustomView")
public class CircleImageView extends ImageView {
    private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP;
    private static final 
 
Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888;
    private static final int COLORDRAWABLE_DIMENSION = 2;
    private static final int DEFAULT_BORDER_WIDTH = 0;
    private static final int DEFAULT_BORDER_COLOR = Color.BLACK;
    private final RectF mDrawableRect = new RectF();
    private final RectF mBorderRect = new RectF();
    private final Matrix mShaderMatrix = new Matrix();
    private final Paint mBitmapPaint = new Paint();
    private final Paint mBorderPaint = new Paint();
    private int mBorderColor = DEFAULT_BORDER_COLOR;
    private int mBorderWidth = DEFAULT_BORDER_WIDTH;
    private Bitmap mBitmap;
    private BitmapShader mBitmapShader;
    private int mBitmapWidth;
    private int mBitmapHeight;
    private float mDrawableRadius;
    private float mBorderRadius;
    private boolean mReady;
    private boolean mSetupPending;
    public CircleImageView(Context context) {
        super(context);
init();
}
    public CircleImageView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
}
    public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CircleImageView, defStyle, 0);
mBorderWidth = a.getDimensionPixelSize(R.styleable.CircleImageView_border_width, DEFAULT_BORDER_WIDTH);
mBorderColor = a.getColor(R.styleable.CircleImageView_border_color, DEFAULT_BORDER_COLOR);
a.recycle();
init();
}
    private void init() {
        super.setScaleType(SCALE_TYPE);
mReady = true;
        if (mSetupPending) {
            setup();
mSetupPending = false;
}
    }
    @Override
public ScaleType getScaleType() {
        return SCALE_TYPE;
}
    @Override
public void setScaleType(ScaleType scaleType) {
        if (scaleType != SCALE_TYPE) {
            throw new IllegalArgumentException(String.format("ScaleType %s not supported.", scaleType));
}
    }
    @Override
public void setAdjustViewBounds(boolean adjustViewBounds) {
        if (adjustViewBounds) {
            throw new IllegalArgumentException("adjustViewBounds not supported.");
}
    }
    @Override
protected void onDraw(Canvas canvas) {
        if (getDrawable() == null) {
            return;
}
        canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius, mBitmapPaint);
        if (mBorderWidth != 0) {
            canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius, mBorderPaint);
}
    }
    @Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
setup();
}
    public int getBorderColor() {
        return mBorderColor;
}
    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();
}
    @Override
public void setImageBitmap(Bitmap bm) {
        super.setImageBitmap(bm);
mBitmap = bm;
setup();
}
    @Override
public void setImageDrawable(Drawable drawable) {
        super.setImageDrawable(drawable);
mBitmap = getBitmapFromDrawable(drawable);
setup();
}
    @Override
public void setImageResource(int resId) {
        super.setImageResource(resId);
mBitmap = getBitmapFromDrawable(getDrawable());
setup();
}
    @Override
public void setImageURI(Uri uri) {
        super.setImageURI(uri);
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;
}
    }
    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);
mBitmapPaint.setShader(mBitmapShader);
mBorderPaint.setStyle(Paint.Style.STROKE);
mBorderPaint.setAntiAlias(true);
mBorderPaint.setColor(mBorderColor);
mBorderPaint.setStrokeWidth(mBorderWidth);
mBitmapHeight = mBitmap.getHeight();
mBitmapWidth = mBitmap.getWidth();
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);
}
}

    res/values/attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="CircleImageView">
        <attr name="border_width" format="dimension" />
        <attr name="border_color" format="color" />
    </declare-styleable>
</resources>

   activity_main.xml 下用上面自定義的View

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.zero.cui.circleimageview.MainActivity">
    <com.zero.cui.circleimageview.CircleImageView
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/circleImageView"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_centerHorizontal="true"
android:src="@drawable/touxiang"
app:border_width="2dp"
app:border_color="#ccc"/>
</RelativeLayout>