CardView不好用，自己写个带border的圆角容器

Posted 2021-08-28 汤米粥

package com.common.base.view;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.os.Build;
import android.util.AttributeSet;
import android.widget.RelativeLayout;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import com.common.base.R;


public class RoundRelativeLayout extends RelativeLayout {
    private Path mPath;
    private Paint mPaint;
    private RectF mRectF;
    private RectF mChildRectF;
    private float mRadius;
    private float mBorderWidth = 1;

    public RoundRelativeLayout(@NonNull Context context) {
        this(context, null);
    }

    public RoundRelativeLayout(@NonNull Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public RoundRelativeLayout(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.RoundRelativeLayout);
        mRadius = ta.getDimension(R.styleable.RoundRelativeLayout_rlRadius, 0);
        mBorderWidth = ta.getDimension(R.styleable.RoundRelativeLayout_rlBorderWidth, 1);
        ta.recycle();
        mPath = new Path();
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mRectF = new RectF();
        mChildRectF = new RectF();
        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));

    }

    public void setRadius(float radius) {
        mRadius = radius;
        postInvalidate();
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mRectF.set(0, 0, w, h);
        mChildRectF.set(mBorderWidth, mBorderWidth, w - mBorderWidth, h - mBorderWidth);
    }

    @SuppressLint("MissingSuperCall")
    @Override
    public void draw(Canvas canvas) {
        draw28(canvas);
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        dispatchDraw27(canvas);
    }

    private void draw28(Canvas canvas) {
        canvas.save();
        canvas.clipPath(genPath());
        super.draw(canvas);
        canvas.restore();

    }

    private void dispatchDraw27(Canvas canvas) {
        canvas.saveLayer(mChildRectF, null, Canvas.ALL_SAVE_FLAG);
        super.dispatchDraw(canvas);
        mPaint.setStyle(Paint.Style.FILL);
        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
        canvas.drawPath(genChildPath(), mPaint);
        canvas.restore();
    }


    private Path genPath() {
        mPath.reset();
        mPath.addRoundRect(mRectF, mRadius, mRadius, Path.Direction.CW);
        return mPath;
    }

    private Path genChildPath() {
        mPath.reset();
        mPath.addRoundRect(mChildRectF, mRadius, mRadius, Path.Direction.CW);
        return mPath;
    }
}

<declare-styleable name="RoundRelativeLayout">
    <attr name="rlRadius" format="dimension" />
    <attr name="rlBorderWidth" format="dimension" />
</declare-styleable>