仿Android 5.0按钮点击效果

最新推荐文章于 2021-05-26 10:19:47 发布

原创最新推荐文章于 2021-05-26 10:19:47 发布 · 548 阅读

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本文介绍了一个自定义的ImageView类MyImageView，该类继承自Android的ImageView，并实现了触摸事件监听及画布上的圆形绘制功能。当按下触摸事件时开始绘制，释放或取消时停止绘制。

public class MyImageView extends ImageView {
    private float pointX = 0f;
    private float pointY = 0f;

    private int count = 1;

    private Paint paint;

    private boolean isDraw = false;

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

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

    public JImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    /**
     * 初始化
     */
    private void init() {
        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setColor(0x35333333);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (isDraw) {
            count += 2;
            canvas.drawCircle(pointX, pointY, count, paint);
            postInvalidateDelayed(16);
        }
        super.onDraw(canvas);
    }

    @Override
    @SuppressLint("ClickableViewAccessibility")
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            isDraw = true;
            pointX = event.getX();
            pointY = event.getY();
            postInvalidate();
            break;
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_MOVE:
        case MotionEvent.ACTION_CANCEL:
            isDraw = false;
            count = 1;
            break;
        }
        return true;
    }
}