怎么在android中通过自定义imageview实现一个圆角图片？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
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（1）在activity_main.xml文件布局，非常简单
2.1注意添加attrs文件，设置图片的属性，然后在java代码中引用属性，在xml文件使用相关属性
（2）MainActivity直接导入上面的布局即可，无需其他操作，如果要写监听或者其他操作，需要特别处理，这里仅仅提供显示
（3）开源的工具类，图片圆角转换工具类
package com.example.administrator.testz;
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.ColorFilter;
import android.graphics.Matrix;
import android.graphics.Outline;
import android.graphics.Paint;
import android.graphics.Rect;
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.os.Build;
import android.support.annotation.ColorInt;
import android.support.annotation.ColorRes;
import android.support.annotation.DrawableRes;
import android.support.annotation.RequiresApi;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewOutlineProvider;
import android.widget.ImageView;
public class CircleImageView extends ImageView {
//参考网址:https://github.com/hdodenhof/CircleImageView
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 static final int DEFAULT_CIRCLE_BACKGROUND_COLOR = Color.TRANSPARENT;
private static final boolean DEFAULT_BORDER_OVERLAY = false;
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 final Paint mCircleBackgroundPaint = new Paint();
private int mBorderColor = DEFAULT_BORDER_COLOR;
private int mBorderWidth = DEFAULT_BORDER_WIDTH;
private int mCircleBackgroundColor = DEFAULT_CIRCLE_BACKGROUND_COLOR;
private Bitmap mBitmap;
private BitmapShader mBitmapShader;
private int mBitmapWidth;
private int mBitmapHeight;
private float mDrawableRadius;
private float mBorderRadius;
private ColorFilter mColorFilter;
private boolean mReady;
private boolean mSetupPending;
private boolean mBorderOverlay;
private boolean mDisableCircularTransformation;
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_civ_border_width, DEFAULT_BORDER_WIDTH);
mBorderColor = a.getColor(R.styleable.CircleImageView_civ_border_color, DEFAULT_BORDER_COLOR);
mBorderOverlay = a.getBoolean(R.styleable.CircleImageView_civ_border_overlay, DEFAULT_BORDER_OVERLAY);
// Look for deprecated civ_fill_color if civ_circle_background_color is not set
if (a.hasValue(R.styleable.CircleImageView_civ_circle_background_color)) {
mCircleBackgroundColor = a.getColor(R.styleable.CircleImageView_civ_circle_background_color,
DEFAULT_CIRCLE_BACKGROUND_COLOR);
} else if (a.hasValue(R.styleable.CircleImageView_civ_fill_color)) {
mCircleBackgroundColor = a.getColor(R.styleable.CircleImageView_civ_fill_color,
DEFAULT_CIRCLE_BACKGROUND_COLOR);
}
a.recycle();
init();
}
private void init() {
super.setScaleType(SCALE_TYPE);
mReady = true;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
setOutlineProvider(new OutlineProvider());
}
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 (mDisableCircularTransformation) {
super.onDraw(canvas);
return;
}
if (mBitmap == null) {
return;
}
if (mCircleBackgroundColor != Color.TRANSPARENT) {
canvas.drawCircle(mDrawableRect.centerX(), mDrawableRect.centerY(), mDrawableRadius, mCircleBackgroundPaint);
}
canvas.drawCircle(mDrawableRect.centerX(), mDrawableRect.centerY(), mDrawableRadius, mBitmapPaint);
if (mBorderWidth > 0) {
canvas.drawCircle(mBorderRect.centerX(), mBorderRect.centerY(), mBorderRadius, mBorderPaint);
}
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
setup();
}
@Override
public void setPadding(int left, int top, int right, int bottom) {
super.setPadding(left, top, right, bottom);
setup();
}
@Override
public void setPaddingRelative(int start, int top, int end, int bottom) {
super.setPaddingRelative(start, top, end, bottom);
setup();
}
public int getBorderColor() {
return mBorderColor;
}
public void setBorderColor(@ColorInt int borderColor) {
if (borderColor == mBorderColor) {
return;
}
mBorderColor = borderColor;
mBorderPaint.setColor(mBorderColor);
invalidate();
}
/**
* @deprecated Use {@link #setBorderColor(int)} instead
*/
@Deprecated
public void setBorderColorResource(@ColorRes int borderColorRes) {
setBorderColor(getContext().getResources().getColor(borderColorRes));
}
public int getCircleBackgroundColor() {
return mCircleBackgroundColor;
}
public void setCircleBackgroundColor(@ColorInt int circleBackgroundColor) {
if (circleBackgroundColor == mCircleBackgroundColor) {
return;
}
mCircleBackgroundColor = circleBackgroundColor;
mCircleBackgroundPaint.setColor(circleBackgroundColor);
invalidate();
}
public void setCircleBackgroundColorResource(@ColorRes int circleBackgroundRes) {
setCircleBackgroundColor(getContext().getResources().getColor(circleBackgroundRes));
}
/**
* Return the color drawn behind the circle-shaped drawable.
*
* @return The color drawn behind the drawable
*
* @deprecated Use {@link #getCircleBackgroundColor()} instead.
*/
@Deprecated
public int getFillColor() {
return getCircleBackgroundColor();
}
/**
* Set a color to be drawn behind the circle-shaped drawable. Note that
* this has no effect if the drawable is opaque or no drawable is set.
*
* @param fillColor The color to be drawn behind the drawable
*
* @deprecated Use {@link #setCircleBackgroundColor(int)} instead.
*/
@Deprecated
public void setFillColor(@ColorInt int fillColor) {
setCircleBackgroundColor(fillColor);
}
/**
* Set a color to be drawn behind the circle-shaped drawable. Note that
* this has no effect if the drawable is opaque or no drawable is set.
*
* @param fillColorRes The color resource to be resolved to a color and
* drawn behind the drawable
*
* @deprecated Use {@link #setCircleBackgroundColorResource(int)} instead.
*/
@Deprecated
public void setFillColorResource(@ColorRes int fillColorRes) {
setCircleBackgroundColorResource(fillColorRes);
}
public int getBorderWidth() {
return mBorderWidth;
}
public void setBorderWidth(int borderWidth) {
if (borderWidth == mBorderWidth) {
return;
}
mBorderWidth = borderWidth;
setup();
}
public boolean isBorderOverlay() {
return mBorderOverlay;
}
public void setBorderOverlay(boolean borderOverlay) {
if (borderOverlay == mBorderOverlay) {
return;
}
mBorderOverlay = borderOverlay;
setup();
}
public boolean isDisableCircularTransformation() {
return mDisableCircularTransformation;
}
public void setDisableCircularTransformation(boolean disableCircularTransformation) {
if (mDisableCircularTransformation == disableCircularTransformation) {
return;
}
mDisableCircularTransformation = disableCircularTransformation;
initializeBitmap();
}
@Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
initializeBitmap();
}
@Override
public void setImageDrawable(Drawable drawable) {
super.setImageDrawable(drawable);
initializeBitmap();
}
@Override
public void setImageResource(@DrawableRes int resId) {
super.setImageResource(resId);
initializeBitmap();
}
@Override
public void setImageURI(Uri uri) {
super.setImageURI(uri);
initializeBitmap();
}
@Override
public void setColorFilter(ColorFilter cf) {
if (cf == mColorFilter) {
return;
}
mColorFilter = cf;
applyColorFilter();
invalidate();
}
@Override
public ColorFilter getColorFilter() {
return mColorFilter;
}
private void applyColorFilter() {
if (mBitmapPaint != null) {
mBitmapPaint.setColorFilter(mColorFilter);
}
}
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 (Exception e) {
e.printStackTrace();
return null;
}
}
private void initializeBitmap() {
if (mDisableCircularTransformation) {
mBitmap = null;
} else {
mBitmap = getBitmapFromDrawable(getDrawable());
}
setup();
}
private void setup() {
if (!mReady) {
mSetupPending = true;
return;
}
if (getWidth() == 0 && getHeight() == 0) {
return;
}
if (mBitmap == null) {
invalidate();
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);
mCircleBackgroundPaint.setStyle(Paint.Style.FILL);
mCircleBackgroundPaint.setAntiAlias(true);
mCircleBackgroundPaint.setColor(mCircleBackgroundColor);
mBitmapHeight = mBitmap.getHeight();
mBitmapWidth = mBitmap.getWidth();
mBorderRect.set(calculateBounds());
mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2.0f, (mBorderRect.width() - mBorderWidth) / 2.0f);
mDrawableRect.set(mBorderRect);
if (!mBorderOverlay && mBorderWidth > 0) {
mDrawableRect.inset(mBorderWidth - 1.0f, mBorderWidth - 1.0f);
}
mDrawableRadius = Math.min(mDrawableRect.height() / 2.0f, mDrawableRect.width() / 2.0f);
applyColorFilter();
updateShaderMatrix();
invalidate();
}
private RectF calculateBounds() {
int availableWidth = getWidth() - getPaddingLeft() - getPaddingRight();
int availableHeight = getHeight() - getPaddingTop() - getPaddingBottom();
int sideLength = Math.min(availableWidth, availableHeight);
float left = getPaddingLeft() + (availableWidth - sideLength) / 2f;
float top = getPaddingTop() + (availableHeight - sideLength) / 2f;
return new RectF(left, top, left + sideLength, top + sideLength);
}
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) + mDrawableRect.left, (int) (dy + 0.5f) + mDrawableRect.top);
mBitmapShader.setLocalMatrix(mShaderMatrix);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
return inTouchableArea(event.getX(), event.getY()) && super.onTouchEvent(event);
}
private boolean inTouchableArea(float x, float y) {
return Math.pow(x - mBorderRect.centerX(), 2) + Math.pow(y - mBorderRect.centerY(), 2) <= Math.pow(mBorderRadius, 2);
}
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
private class OutlineProvider extends ViewOutlineProvider {
@Override
public void getOutline(View view, Outline outline) {
Rect bounds = new Rect();
mBorderRect.roundOut(bounds);
outline.setRoundRect(bounds, bounds.width() / 2.0f);
}
}
}看完上述内容，你们掌握怎么在android中通过自定义imageview实现一个圆角图片的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注创新互联行业资讯频道，感谢各位的阅读！
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