倒计时

最新推荐文章于 2023-08-10 20:23:42 发布

原创最新推荐文章于 2023-08-10 20:23:42 发布 · 286 阅读

0 ·

CC 4.0 BY-SA版权

本文介绍了一个自定义的Android视图组件TimeCountView，用于显示倒计时效果。该组件通过继承View并重写onDraw方法来绘制倒计时数字，并通过启动内部线程进行时间递减。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

倒计时


public class TimeCountView extends View implements Runnable {
    private Paint mPaint;
    private int count = 10;//倒计时
    private int mWidth;
    private int mHeight;
    private int mTextSize;//字体大小
    private Thread mThread;
    private Rect rect;
    private int baseline;//文字基线

    public TimeCountView(Context context) {
        this(context, null);
    }

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

    public TimeCountView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mTextSize = 200;
        mThread = new Thread(this);
        init();
    }

    private void init() {
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setDither(true);
        mPaint.setColor(Color.WHITE);
        mPaint.setTextSize(mTextSize);
        mPaint.setFakeBoldText(true);
        mPaint.setTextAlign(Paint.Align.CENTER);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawColor(Color.BLACK);
        canvas.drawText(count + "", rect.centerX(), baseline, mPaint);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mWidth = getMeasuredWidth();
        mHeight = getMeasuredHeight();
        measureBaseLine();
    }

    /**
     * 计算文字的基线
     */
    private void measureBaseLine() {
        rect = new Rect(0, 0, mWidth, mHeight);
        Paint.FontMetricsInt f = mPaint.getFontMetricsInt();
        baseline = rect.centerY() - (f.bottom + f.top) / 2;
    }

    @Override
    public void run() {
        try {
            while (count > 0) {
                postInvalidate();
                count--;
                Thread.sleep(1000);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 开启倒计时
     */
    public void start() {
        mThread.start();
    }
}