Android自定义view 之 圆环ImageView 和 圆角按钮Button

自定义View的入门点. 主要是练练手, 关键是继承对应的组件类, 利用paint画笔的属性设置, 在Canvas上绘画实现.

圆环ImageView

public class CircleImageView extends ImageView{
	private final Paint paint;
	private final Context context; 
	
	
	
	public CircleImageView(Context context, AttributeSet attrs) {
		  super(context, attrs);
		  
		  this.context = context;
		  this.paint = new Paint();
		  this.paint.setAntiAlias(true); 		//消除锯齿 
		  this.paint.setStyle(Style.STROKE);  //绘制空心圆或 空心矩形 
	} 
	
	
	@Override
	protected void onDraw(Canvas canvas){
		int center = getWidth()/2;
		int innerCircle = utils.dip2px(context, 50); //内圆半径
		int ringWidth = utils.dip2px(context, 5);   //圆环宽度
		
		this.paint.setARGB(255, 138, 43, 226);
		this.paint.setStrokeWidth(2);
		canvas.drawCircle(center, center, innerCircle, this.paint);
		
		this.paint.setARGB(255,200,85,198);
		this.paint.setStrokeWidth(ringWidth);
		canvas.drawCircle(center, center, innerCircle+utils.dip2px(context, 10), this.paint);
		
		this.paint.setARGB(255,200,102,75);
		this.paint.setStrokeWidth(ringWidth);
		canvas.drawCircle(center, center, innerCircle+utils.dip2px(context, 20), this.paint);
		
		super.onDraw(canvas);
		
	}
	
	
}

圆角按钮Button

/**
 * 自定义圆角Button
 * @author KinHo
 *
 */
public class BorderButton_1 extends Button{
	
	public BorderButton_1(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
	
	
	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		super.onDraw(canvas);
		// 实例化一支画笔
		Paint paint = new Paint();
		paint.setStrokeWidth(1);
		paint.setStyle(Style.STROKE);	// 设置样式-空心矩形
		paint.setColor(android.graphics.Color.DKGRAY);	// 设置颜色 
		paint.setAntiAlias(true);	//抗锯齿
		RectF rectF = new RectF(2,0,this.getWidth()-2,this.getHeight()-2);
		canvas.drawRoundRect(rectF, 20, 20, paint);	// 绘制一个矩形 
	}
	
	
}

效果图:



自定义View是终于知识点, 多练习熟悉对Paint的使用很重要.