如何自定义View将图片设置成圆形

图片：

Activity中：
package com.bnyt.cloudplatform.view;

import android.content.Context;
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.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.text.TextPaint;
import android.util.AttributeSet;

/**
* Created by apple on 2017/10/21.
*/

public class CircleImageView extends android.support.v7.widget.AppCompatImageView {

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;

// 圆形边框的厚度默认值。
// 如果是0，则没有天蓝色渐变的边框。
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;
private final Paint mFlagBackgroundPaint = new Paint();
private final TextPaint mFlagTextPaint = new TextPaint();
private String mFlagText;
private boolean mShowFlag = false;
private Rect mFlagTextBounds = new Rect();

Shader mSweepGradient = null;

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);

    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.save();
        canvas.rotate(20, getWidth() / 2, getHeight() / 2);
        canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius,
                mBorderPaint);
        canvas.restore();
    }

    if (mShowFlag && mFlagText != null) {
        canvas.drawArc(mBorderRect, 40, 100, false, mFlagBackgroundPaint);
        mFlagTextPaint.getTextBounds(mFlagText, 0, mFlagText.length(),
                mFlagTextBounds);
        canvas.drawText(mFlagText, getWidth() / 2,
                (float) ((3 + Math.cos((float) (Math.PI * 5 / 18)))
                        * getHeight() / 4 + mFlagTextBounds.height() / 3),
                mFlagTextPaint);

    }

}

@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;
}

/**
 * @param borderWidth
 *   圆形的边框厚度。
 */
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);

    mFlagBackgroundPaint.setColor(Color.BLACK & 0x66FFFFFF);
    mFlagBackgroundPaint.setFlags(TextPaint.ANTI_ALIAS_FLAG);

    mFlagTextPaint.setFlags(TextPaint.ANTI_ALIAS_FLAG);
    mFlagTextPaint.setTextAlign(Paint.Align.CENTER);
    mFlagTextPaint.setColor(Color.WHITE);
    mFlagTextPaint
            .setTextSize(getResources().getDisplayMetrics().density * 18);

    mSweepGradient = new SweepGradient(getWidth() / 2, getHeight() / 2,
            new int[] { Color.rgb(255, 255, 255), Color.rgb(1, 209, 255) },
            null);

    mBorderPaint.setShader(mSweepGradient);

    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);
}

public void setShowFlag(boolean show) {
    mShowFlag = show;
    invalidate();
}

public void setFlagText(String text) {
    mFlagText = text;
    invalidate();
}

}

布局文件中：

                <com.bnyt.cloudplatform.view.CircleImageView
                    android:id="@+id/iv_head"
                    android:layout_width="88dp"
                    android:layout_height="88dp"
                    android:layout_gravity="center"
                    android:src="@drawable/li_changlong" />