android 方式实现imageview圆角

  1. 自定义imageview
public class RoundImageView extends ImageView {
    /**
     * 图片的类型,圆形or圆角
     */
    private int type;
    public static final int TYPE_CIRCLE = 0;
    public static final int TYPE_ROUND = 1;

    /**
     * 圆角大小的默认值
     */
    private static final int BODER_RADIUS_DEFAULT = 10;
    /**
     * 圆角的大小
     */
    private int mBorderRadius;

    /**
     * 绘图的Paint
     */
    private Paint mBitmapPaint;
    /**
     * 圆角的半径
     */
    private int mRadius;
    /**
     * 3x3 矩阵,主要用于缩小放大
     */
    private Matrix mMatrix;
    /**
     * 渲染图像,使用图像为绘制图形着色
     */
    private BitmapShader mBitmapShader;
    /**
     * view的宽度
     */
    private int mWidth;
    private RectF mRoundRect;

    /**
     * 构造函数:获取自定义属性
     */
    public RoundImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mMatrix = new Matrix();
        mBitmapPaint = new Paint();
        mBitmapPaint.setAntiAlias(true);

        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.RoundImageView);
        mBorderRadius = a.getDimensionPixelSize(
                R.styleable.RoundImageView_borderRadius, (int) TypedValue
                        .applyDimension(TypedValue.COMPLEX_UNIT_DIP,
                                BODER_RADIUS_DEFAULT, getResources()
                                        .getDisplayMetrics()));// 默认为10dp
        type = a.getInt(R.styleable.RoundImageView_type, TYPE_CIRCLE);// 默认为Circle
        a.recycle();

    }

    /**
     * 关于view的宽高:主要用于当设置类型为圆形时,我们强制让view的宽和高一致
     */
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.e("TAG", "onMeasure");
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        /**
         * 如果类型是圆形,则强制改变view的宽高一致,以小值为准;如果是圆角则不用管宽高问题
         */
        if (type == TYPE_CIRCLE) {
            mWidth = Math.min(getMeasuredWidth(), getMeasuredHeight());
            mRadius = mWidth / 2;
            setMeasuredDimension(mWidth, mWidth);
        }

    }

    /**
     * 1. 设置BitmapShader
     * 2. 绘制
     */
    @Override
    protected void onDraw(Canvas canvas) {
        if (getDrawable() == null) {
            return;
        }
        setUpShader();

        if (type == TYPE_ROUND) {
            canvas.drawRoundRect(mRoundRect, mBorderRadius, mBorderRadius,
                    mBitmapPaint);
        } else {
            canvas.drawCircle(mRadius, mRadius, mRadius, mBitmapPaint);
            // drawSomeThing(canvas);
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        // 圆角图片的范围
        if (type == TYPE_ROUND)
            mRoundRect = new RectF(0, 0, getWidth(), getHeight());
    }

    /**
     * 初始化BitmapShader//给paint附加一个具有某种魔力(缩放)的shader
     * 1. drawable转化为我们的bitmap
     * 2. 设置shader 的mode
     * 3. 设置scale: 因为最终缩放完成的图片一定要大于我们的view的区域
     * 4. scale设置给matrix
     * 5. matrix设置给shader
     * 6. shader设置给paint
     */
    private void setUpShader() {
        Drawable drawable = getDrawable();
        if (drawable == null) {
            return;
        }

        Bitmap bmp = drawableToBitamp(drawable);
        // 将bmp作为着色器,就是在指定区域内绘制bmp;此构造方法用的是拉伸mode: clamp
        mBitmapShader = new BitmapShader(bmp, CLAMP, CLAMP);
        float scale = 1.0f;
        if (type == TYPE_CIRCLE) {
            // 拿到bitmap宽或高的小值//我们需要画正方形
            int bSize = Math.min(bmp.getWidth(), bmp.getHeight());
            scale = mWidth * 1.0f / bSize;

        } else if (type == TYPE_ROUND) {
            // 如果图片的宽或者高与view的宽高不匹配,计算出需要缩放的比例;缩放后的图片的宽高,一定要大于我们view的宽高;所以我们这里取大值;//view的宽度/bitmap的宽度=缩放倍数
            scale = Math.max(getWidth() * 1.0f / bmp.getWidth(), getHeight()
                    * 1.0f / bmp.getHeight());
        }
        // shader的变换矩阵,我们这里主要用于放大或者缩小
        mMatrix.setScale(scale, scale);
        // 设置变换矩阵
        mBitmapShader.setLocalMatrix(mMatrix);
        // 先给paint设置shader;然后画笔会有所不同哦,例如
        mBitmapPaint.setShader(mBitmapShader);
    }

    /**
     * drawable转bitmap
     *
     * @param drawable
     * @return
     */
    private Bitmap drawableToBitamp(Drawable drawable) {
        if (drawable instanceof BitmapDrawable) {
            BitmapDrawable bd = (BitmapDrawable) drawable;
            return bd.getBitmap();
        }
        //以下为drawable转bitmap的通用方法
        int w = drawable.getIntrinsicWidth();
        int h = drawable.getIntrinsicHeight();
        Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, w, h);
        drawable.draw(canvas);
        return bitmap;
    }

    /**
     * 添加一个方法
     * bitmap转drawable
     */
    private Drawable bitmapToDrawable(Bitmap bitmap) {
        Drawable drawable = new BitmapDrawable(null, bitmap);
        return drawable;
    }

    //状态存储与恢复
    private static final String STATE_INSTANCE = "state_instance";
    private static final String STATE_TYPE = "state_type";
    private static final String STATE_BORDER_RADIUS = "state_border_radius";

    @Override
    protected Parcelable onSaveInstanceState() {
        Bundle bundle = new Bundle();
        bundle.putParcelable(STATE_INSTANCE, super.onSaveInstanceState());
        bundle.putInt(STATE_TYPE, type);
        bundle.putInt(STATE_BORDER_RADIUS, mBorderRadius);
        return bundle;
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        if (state instanceof Bundle) {
            Bundle bundle = (Bundle) state;
            super.onRestoreInstanceState(((Bundle) state)
                    .getParcelable(STATE_INSTANCE));
            this.type = bundle.getInt(STATE_TYPE);
            this.mBorderRadius = bundle.getInt(STATE_BORDER_RADIUS);
        } else {
            super.onRestoreInstanceState(state);
        }

    }

    /**
     * 动态修改圆角大小
     * */
    public void setBorderRadius(int borderRadius) {
        int pxVal = dp2px(borderRadius);
        if (this.mBorderRadius != pxVal) {
            this.mBorderRadius = pxVal;
            invalidate();
        }
    }
    /**
     * 动态设置type
     * */
    public void setType(int type) {
        if (this.type != type) {
            this.type = type;
            if (this.type != TYPE_ROUND && this.type != TYPE_CIRCLE) {
                this.type = TYPE_CIRCLE;
            }
            requestLayout();
        }

    }

    private int dp2px(int dpVal) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
                dpVal, getResources().getDisplayMetrics());
    }

  1. 自定义控件属性
<!--圆角图片设计-->
    <attr name="borderRadius" format="dimension" />
    <attr name="type">
        <enum name="circle" value="0" />
        <enum name="round" value="1" />
    </attr>
    <declare-styleable name="RoundImageView">
        <attr name="borderRadius" />
        <attr name="type" />
    </declare-styleable>
  1. 使用方式
    1. <?xml version="1.0" encoding="utf-8"?>
      <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:app="http://schemas.android.com/apk/res-auto"
          android:id="@+id/relative_reconmmend"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:orientation="horizontal">
          <RoundImageView
              android:id="@+id/iv_grid_img"
              android:layout_width="120dp"
              android:layout_height="120dp"
              android:scaleType="fitXY"
              android:src="@drawable/icon_no_pic_long"
              app:borderRadius="5dp"
              app:type="round" />
      </RelativeLayout>        
      
按照正常的实例化,就可以了成功了,优点就是没有内存溢出了

参考文章鸿洋显示效果和鸿洋的一样,不在显示了

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转载自blog.csdn.net/shuijianbaozi/article/details/84035460