Android 自定义布局控件-圆形RelativeLayout

Android 自定义布局控件-圆形RelativeLayout

转自“姜徕”，原文链接：https://blog.csdn.net/jiang001002jay/article/details/61418338

效果图 ：

 

创建自定义类：CircleRelativeLayout.java

package com.jzy.circularlayout;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.widget.RelativeLayout;

public class CircleRelativeLayout extends RelativeLayout {
    private int color;
    private int[] colors;
    private int alpha;
    public CircleRelativeLayout(Context context) {
        super(context);
    }
    public CircleRelativeLayout(Context context, AttributeSet attrs) {
        super(context,attrs);
        init(context,attrs);
        setWillNotDraw(false);
    }
    private void init(Context context, AttributeSet attrs) {
        TypedArray array = context.obtainStyledAttributes(attrs,
                R.styleable.CircleRelativeLayoutLayout);
        color = array.getColor(R.styleable.CircleRelativeLayoutLayout_background_color,0X0000000);
        alpha = array.getInteger(R.styleable.CircleRelativeLayoutLayout_background_alpha,100);
        setColors();
        array.recycle();
    }
    @Override
    protected void onDraw(Canvas canvas) { //构建圆形
        int width = getMeasuredWidth();
        Paint mPaint = new Paint();
        mPaint.setARGB(alpha,colors[0],colors[1],colors[2]);
        mPaint.setAntiAlias(true);
        float cirX = width / 2;
        float cirY = width / 2;
        float radius = width / 2;
        canvas.drawCircle(cirX, cirY, radius, mPaint);
        super.onDraw(canvas);
    }

    public void setColor(int color) { //设置背景色
        this.color = color;
        setColors();
        invalidate();
    }

    public void setAlhpa(int alhpa) { //设置透明度
        this.alpha = alhpa;
        invalidate();
    }


    public void setColors() {
        int red = (color & 0xff0000) >> 16;
        int green = (color & 0x00ff00) >> 8;
        int blue = (color & 0x0000ff);
        this.colors = new int[]{red,green,blue};
    }

}

• 添加自定义属性 values/attr.xml

   

• 布局文件

 

• 获取和设置控件

  public class MainActivity extends Activity {
      CircleRelativeLayout crlayout;
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          crlayout = (CircleRelativeLayout) findViewById(R.id.crlayout);
          crlayout.setColor(getResources().getColor(R.color.colorAccent));
          crlayout.setAlhpa(160);
      }
  }