Android自定义圆形图片工具类(CTRL+C加CTRL+V直接使用)

先贴一下工具类的代码！可直接复制粘贴

public class RoundImageView extends ImageView {


    private Paint mPaint; //画笔

    private int mRadius; //圆形图片的半径

    private float mScale; //图片的缩放比例

    public RoundImageView(Context context) {
        super(context);
    }

    public RoundImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public RoundImageView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //因为是圆形图片，所以应该让宽高保持一致
        int size = Math.min(getMeasuredWidth(), getMeasuredHeight());
        mRadius = size / 2;

        setMeasuredDimension(size, size);
    }

    @Override
    protected void onDraw(Canvas canvas) {

        mPaint = new Paint();
        Bitmap bitmap = drawableToBitmap(getDrawable());

        //初始化BitmapShader，传入bitmap对象
        BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

        //计算缩放比例
        mScale = (mRadius * 2.0f) / Math.min(bitmap.getHeight(), bitmap.getWidth());

        Matrix matrix = new Matrix();
        matrix.setScale(mScale, mScale);
        bitmapShader.setLocalMatrix(matrix);


        mPaint.setShader(bitmapShader);

        //画圆形，指定好中心点坐标、半径、画笔
        canvas.drawCircle(mRadius, mRadius, mRadius, mPaint);
    }

    //写一个drawble转BitMap的方法
    private Bitmap drawableToBitmap(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;
    }

}

　现在一个圆形图片已经完成了90%，接下来就是布局文件，在这里我只写了一个简单的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center">

    <com.bc.rcmpapp.util.RoundImageView
        android:id="@+id/round_img"
        android:scaleType="fitCenter"
        android:layout_width="30dp"
        android:layout_height="30dp"
　　　　 android:src="@drawable/ic_launcher"/> 

</LinearLayout>

　　最后需要在Activity中加载！找到对应的布局即可

　　

RoundImageView imageView = (RoundImageView)findViewById(R.id.round_img);

　　

　　紫色的标记是需要声明图片为自己定义的RoundImageView.java文件的位置

　　红色标注的需要声明对应的RoundImageView

　　接下来圆形图片就成功了！继续对图片进行操作吧