Question

我有Button，按下后，应该开始倒计时，并在按钮上显示倒数。

我该怎么办？

Answer 1

试试这个

public class CountDown extends Activity implements OnClickListener {

    Button btn;
    int i=0, second = 3;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        btn = (Button)findViewById(R.id.btn);
        btn.setOnClickListener( this );
    }

    @Override
    public void onClick(View v) {
        new Thread( new Runnable() {
                public void run() {
                    while( i != second ) {
                        try {
                            handle.sendMessage( handle.obtainMessage());
                            Thread.sleep(1000);
                        } catch( Throwable t) {

                        }   
                    }
                }  

                Handler handle = new Handler() {
                    public void handleMessage( Message msg) {
                        btn.setText( ""+ second );
                        second--;
                    }           
                };
        }).start();   

    }
}

Answer 2

以下代码将非常简单地实现您的要求。现在这非常简单。您需要实施onFinish()并可能实施onTick()一点。但这是能够轻松完成您想要的代码的最少代码。

您想要做的是使用随android api提供的CountDownTimer。

private long countDown = 3000;

private long interval = 1000;

private CountDownTimer countDownTimer;

    this.countDownTimer = new CountDownTimer(this.countDown, this.interval) {

        @Override
        public void onTick(long millisUntilFinished) {
            colorButton.setText(Long.toString(millisUntilFinished/1000));
        }

        @Override
        public void onFinish() {
            // TODO Auto-generated method stub

        }
    };

    this.colorButton.setText(Long.toString(this.countDown/1000));
    this.colorButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            countDownTimer.start();
        }
    });

如何设置按钮的倒计时？

2 个答案: