android 动态长方形实现

package com.zeroone.loginmodule.fragment;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.Nullable;

public class DynamicRectangleView extends View {

    private Paint paint;
    private int rectangleLength;

    public DynamicRectangleView(Context context) {
        super(context);
        init();
    }

    public DynamicRectangleView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    private void init() {
        paint = new Paint();
        paint.setColor(Color.BLUE);
        paint.setStyle(Paint.Style.FILL);
        rectangleLength = 100; // 默认长度
    }

    public void setRectangleLength(int length) {
        rectangleLength = length;
        invalidate(); // 重绘View
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 绘制长方形
        canvas.drawRect(0,
                0,
                rectangleLength,
                getHeight(),
                paint);
    }
}