自定义CircleImageView(一)

最新推荐文章于 2021-05-25 15:26:11 发布

000wen_Android

最新推荐文章于 2021-05-25 15:26:11 发布

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本文链接：https://blog.youkuaiyun.com/aiguoguo000/article/details/51209084

本文介绍如何自定义一个圆形ImageView，并支持边框颜色和宽度的设置。通过创建属性文件和继承ImageView，实现圆形图片显示效果。

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CircleImageView的使用

创建属性文件：attrs.xml，创建路径为—— res/values/attrs.xml ，如下：

<pre name="code" class="html"><?xml version="1.0" encoding="utf-8"?>
<resources>
    <!-- 自定义圆形图片 -->
    <declare-styleable name="CircleImageView" >
        <attr name="border_color" format="color"></attr>
        <attr name="border_width" format="dimension"></attr>
    </declare-styleable>
<resources>

自定义CircleImageView继承ImageView:

package com.wen.guo.view;

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.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;

import com.wen.guo.R;

//继承自 ImageView
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;

    // colordrawable_dimension
    private static final int COLORDRAWABLE_DIMENSION = 1;

    // default_border_width
    private static final int DEFAULT_BORDER_WIDTH = 0;
    // default_border_color
    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);
    }

    public CircleImageView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        super.setScaleType(SCALE_TYPE);

        Log.i("circle" , "CircleImageView");

        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();

        mReady = true;

        if (mSetupPending) {
            setup();
            mSetupPending = false;
        }
    }

    @Override
    public ScaleType getScaleType() {

        Log.i("circle" , "getScaleType");
        return SCALE_TYPE;
    }

    @Override
    public void setScaleType(ScaleType scaleType) {

        Log.i("circle" , "setScaleType");
        if (scaleType != SCALE_TYPE) {
            throw new IllegalArgumentException(String.format(
                    "ScaleType %s not supported.", scaleType));
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {

        Log.i("circle" , "onDraw");
        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);

        Log.i("circle", "onSizeChanged");
        setup();
    }

    public int getBorderColor() {

        Log.i("circle" , "getBorderColor");
        return mBorderColor;
    }

    public void setBorderColor(int borderColor) {


        Log.i("circle" , "setBorderColor");
        if (borderColor == mBorderColor) {
            return;
        }

        mBorderColor = borderColor;
        mBorderPaint.setColor(mBorderColor);
        invalidate();
    }

    public int getBorderWidth() {

        Log.i("circle" , "getBorderWidth");

        return mBorderWidth;
    }

    public void setBorderWidth(int borderWidth) {

        Log.i("circle" , "setBorderWidth");
        if (borderWidth == mBorderWidth) {
            return;
        }

        mBorderWidth = borderWidth;
        setup();
    }

    /*
     * 给ImageView设置图片的方法就是setImageXXX，不管你是用JAVA代码设置，还是在XML里面用src，
     * 它最终还是调用JAVA的setImageXXX方法,在这些个方法的最后一定有一个invalidate的方法，让其调用onDraw。
     * 
     * 它们在设置完图片之后必定会调用setup方法，其实这个方法就是一个初始化操作而已， 但是在setup的结束地方也调用了invalidate
     */
    @Override
    public void setImageBitmap(Bitmap bm) {
        super.setImageBitmap(bm);

        Log.i("circle", "setImageBitmap");
        mBitmap = bm;
        setup();
    }

    @Override
    public void setImageDrawable(Drawable drawable) {

        super.setImageDrawable(drawable);

        Log.i("circle", "setImageDrawable");
        mBitmap = getBitmapFromDrawable(drawable);
        setup();
    }

    @Override
    public void setImageResource(int resId) {
        super.setImageResource(resId);

        Log.i("circle", "setImageResource");
        mBitmap = getBitmapFromDrawable(getDrawable());
        setup();
    }

    private Bitmap getBitmapFromDrawable(Drawable drawable) {

        Log.i("circle" , "getBitmapFromDrawable");
        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;
        }
    }

    /*
     * 它巧妙的用这个mBitmap为空，如果这个View还没有被设置图片则不会执行下面的方法
     * 
     * 这个方法应当是在onMeasure之后调用的，我们知道图片设置成功之后，一定是在onMeasure之后，
     * 
     *    所以它并没有逃脱自定义控件的的逻辑
     *    
     *    1、重写onMeasure计算或者设置一些高度、宽度等数据，
     *    2、重写onDraw 
     *    3、重写onTouch做一些事件处理或者计算，
     *    
     *    它只是通过一个mBitmap的防空来判断它是在绘制成功之后的做的事情。
     */
    private void setup() {

        Log.i("circle" , "setup");
        if (!mReady) {
            mSetupPending = true;
            return;
        }

        //这个mBitmap比较妙，只有当有图片被设置以后才会开始执行下面的方法。
        if (mBitmap == null) {
            return;
        }

        //使用一张位图作为纹理对某一区域进行填充，例如我们drawCircle，
        //它就会对这个circle里面进行填充,它的两个参数就是对X，Y轴进行填充的一些规则。
        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();

        // 整个图像的显示区域：即全部的View大小区域。
        mBorderRect.set(0, 0, getWidth(), getHeight());
        mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2,
                (mBorderRect.width() - mBorderWidth) / 2);

        // 图片显示的区域：即View的大小区域减去边界的大小。
        mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width()
                - mBorderWidth, mBorderRect.height() - mBorderWidth);
        // 图片的半径大小取图片小边。
        mDrawableRadius = Math.min(mDrawableRect.height() / 2,
                mDrawableRect.width() / 2);

        updateShaderMatrix();
        invalidate();
    }

    private void updateShaderMatrix() {

        Log.i("circle" , "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);
    }

}

在布局文件中引入，自定义控件，代码如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:mine="http://schemas.android.com/apk/res/com.wen.guo"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:orientation="horizontal" 
    android:background="#42A6FF">
    
	<com.yuu.post.View.CircleImageView
	    android:id="@+id/header_layout_ui_civ_left"
	    android:contentDescription="@null"
	    android:layout_width="40dp"
	    android:layout_height="40dp"
	    android:layout_margin="5dp"
	    android:src="@drawable/user_default_head"
	    mine:border_width="2dp"
	    mine:border_color="#F2F2F3"/>
</LinearLayout>