android圆形图片显示ImageView超简单控件

关于android显示圆形图片的控件

第一次写技术类博客，先来个简单的，话不多说，只是码上。

1.先创建一个View。

public class RoundImageView extends ImageView {

    /** 图片的类型，圆形or圆角 */
    private int type;
    private static final int TYPE_CIRCLE = 0;
    private 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;

    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();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (type == TYPE_CIRCLE) {
            mWidth = Math.min(getMeasuredWidth(), getMeasuredHeight());
            mRadius = mWidth / 2;
            setMeasuredDimension(mWidth, mWidth);
        }

    }

    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
        mBitmapShader = new BitmapShader(bmp, TileMode.CLAMP, TileMode.CLAMP);
        float scale = 1.0f;
        if (type == TYPE_CIRCLE) {
            int bSize = Math.min(bmp.getWidth(), bmp.getHeight());
            scale = mWidth * 1.0f / bSize;

        } else if (type == TYPE_ROUND) {
            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);
        // 设置shader
        mBitmapPaint.setShader(mBitmapShader);
    }

    private Bitmap drawableToBitamp(Drawable drawable) {
        if (drawable instanceof BitmapDrawable) {
            BitmapDrawable bd = (BitmapDrawable) drawable;
            return bd.getBitmap();
        }
        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;
    }

    @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);
        }
    }

    @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());
    }
}

2.创建布局文件XML,”…”为该View的路径

"1.0" encoding="utf-8"?>
"match_parent"
    android:layout_height="match_parent"
    >
<...RoundImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

完成了，觉得还可以的小伙伴，赶紧试试吧