这篇文章将为大家详细讲解有关android中怎么通过自定义imageview实现圆角图片，文章内容质量较高，因此小编分享给大家做个参考，希望大家阅读完这篇文章后对相关知识有一定的了解。
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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); } }}
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