android开源项目源码解析(一)----CircleImageView的源码解析
2016-03-15 19:13
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CircleImageView的代码很简洁,因此先将此工程作为源码解析系列的第一篇文章.
解析说明都在代码里了。
解析说明都在代码里了。
/* * Copyright 2014 - 2015 Henning Dodenhof * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package de.hdodenhof.circleimageview; 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.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.support.annotation.ColorInt; import android.support.annotation.ColorRes; import android.support.annotation.DrawableRes; import android.util.AttributeSet; import android.widget.ImageView; public class CircleImageView extends ImageView { private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP;//这里限制了只要一种模式: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_FILL_COLOR = Color.TRANSPARENT; private static final boolean DEFAULT_BORDER_OVERLAY = false; private final RectF mDrawableRect = new RectF(); private final RectF mBorderRect = new RectF(); //用来变换 mBitmapShader,从而影响 mBitmapPaint的显示效果 private final Matrix mShaderMatrix = new Matrix(); private final Paint mBitmapPaint = new Paint(); private final Paint mBorderPaint = new Paint(); private final Paint mFillPaint = new Paint(); private int mBorderColor = DEFAULT_BORDER_COLOR; private int mBorderWidth = DEFAULT_BORDER_WIDTH; private int mFillColor = DEFAULT_FILL_COLOR; private Bitmap mBitmap; private BitmapShader mBitmapShader; private int mBitmapWidth; private int mBitmapHeight; private float mDrawableRadius; private float mBorderRadius; private ColorFilter mColorFilter;//滤镜效果,用在中间的bitmap上 private boolean mReady; private boolean mSetupPending; private boolean mBorderOverlay; public CircleImageView(Context context) { super(context); init(); } public CircleImageView(Context context, AttributeSet attrs) { this(context, attrs, 0); } //构造方法,获取属性文件中的定义,不必细说 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); mFillColor = a.getColor(R.styleable.CircleImageView_civ_fill_color, DEFAULT_FILL_COLOR); a.recycle(); init(); } //初始化方法,主要是设置ScaleType,ScaleType被限定为center_crop模式 private void init() { super.setScaleType(SCALE_TYPE); mReady = true; if (mSetupPending) { setup(); mSetupPending = false; } } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); setup();//实现了refresh功能,当属性改变时,调用此方法,完成刷新界面的功能 } @Override protected void onDraw(Canvas canvas) { if (mBitmap == null) { return; } //底色 mFillColor --> 画笔 mFillPaint if (mFillColor != Color.TRANSPARENT) { canvas.drawCircle(getWidth() / 2.0f, getHeight() / 2.0f, mDrawableRadius, mFillPaint); } canvas.drawCircle(getWidth() / 2.0f, getHeight() / 2.0f, mDrawableRadius, mBitmapPaint); //边色 mBorderColor --> 画笔 mBorderPaint if (mBorderWidth != 0) { canvas.drawCircle(getWidth() / 2.0f, getHeight() / 2.0f, mBorderRadius, mBorderPaint); } } 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); mFillPaint.setStyle(Paint.Style.FILL); mFillPaint.setAntiAlias(true); mFillPaint.setColor(mFillColor); mBitmapHeight = mBitmap.getHeight(); mBitmapWidth = mBitmap.getWidth(); mBorderRect.set(0, 0, getWidth(), getHeight()); mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2.0f, (mBorderRect.width() - mBorderWidth) / 2.0f); mDrawableRect.set(mBorderRect); if (!mBorderOverlay) { mDrawableRect.inset(mBorderWidth, mBorderWidth); } mDrawableRadius = Math.min(mDrawableRect.height() / 2.0f, mDrawableRect.width() / 2.0f); updateShaderMatrix(); invalidate(); } private void updateShaderMatrix() { float scale; float dx = 0; float dy = 0; mShaderMatrix.set(null); //这里判断长宽比例,即图片的实际长宽比例与view的长宽比例 //如果图片更"扁",则缩放的尺寸按照两者的高度来定 //如果图片更"瘦",则缩放的尺寸按照两者的宽度来定 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); //可以简单的将BitmapShader类用来给Paint设置"填充颜色",这种说法其实并不准确,shader"填充"效果针对的范围是整个canvas, //而paint显示的是这个paint实时画出来的部分。 //shader可以设置matrix,用来缩放或位移 mBitmapShader.setLocalMatrix(mShaderMatrix); } @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."); } } public int getBorderColor() { return mBorderColor; } public void setBorderColor(@ColorInt int borderColor) { if (borderColor == mBorderColor) { return; } mBorderColor = borderColor; mBorderPaint.setColor(mBorderColor); invalidate(); } public void setBorderColorResource(@ColorRes int borderColorRes) { setBorderColor(getContext().getResources().getColor(borderColorRes)); } public int getFillColor() { return mFillColor; } public void setFillColor(@ColorInt int fillColor) { if (fillColor == mFillColor) { return; } mFillColor = fillColor; mFillPaint.setColor(fillColor); invalidate(); } public void setFillColorResource(@ColorRes int fillColorRes) { setFillColor(getContext().getResources().getColor(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(); } @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(@DrawableRes int resId) { super.setImageResource(resId); mBitmap = getBitmapFromDrawable(getDrawable()); setup(); } @Override public void setImageURI(Uri uri) { super.setImageURI(uri); mBitmap = uri != null ? getBitmapFromDrawable(getDrawable()) : null; setup(); } @Override public void setColorFilter(ColorFilter cf) { if (cf == mColorFilter) { return; } mColorFilter = cf; mBitmapPaint.setColorFilter(mColorFilter); invalidate(); } 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) { //COLORDRAWABLE_DIMENSION == 2,如果是ColorDrawable类型的,就取2x2大小 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; } } }
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