Android实现计时与倒计时的几种技巧

发布时间：2021-12-18 17:26:09 所属栏目：教程来源：互联网

导读：Android实现计时与倒计时的五种方法：方法一 Timer与TimerTask（Java实现） public class timerTask extends Activity{ private int recLen = 11; private TextView txtView; Timer timer = new Timer(); public void onCreate(Bundle savedInstanceState){

Android实现计时与倒计时的五种方法：

方法一

Timer与TimerTask（Java实现）

public class timerTask extends Activity{

    private int recLen = 11;
    private TextView txtView;
    Timer timer = new Timer();

    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);

        setContentView(R.layout.timertask);
        txtView = (TextView)findViewById(R.id.txttime);

        timer.schedule(task, 1000, 1000);       // timeTask
    }

    TimerTask task = new TimerTask() {
        @Override
        public void run() {

            runOnUiThread(new Runnable() {      // UI thread
                @Override
                public void run() {
                    recLen--;
                    txtView.setText(""+recLen);
                    if(recLen < 0){
                        timer.cancel();
                        txtView.setVisibility(View.GONE);
                    }
                }
            });
        }
    };
}
方法二

TimerTask与Handler（不用Timer的改进型）

public class timerTask extends Activity{
    private int recLen = 11;
    private TextView txtView;
    Timer timer = new Timer();

    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);

        setContentView(R.layout.timertask);
        txtView = (TextView)findViewById(R.id.txttime);

        timer.schedule(task, 1000, 1000);       // timeTask
    }

    final Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg){
            switch (msg.what) {
            case 1:
                txtView.setText(""+recLen);
                if(recLen < 0){
                    timer.cancel();
                    txtView.setVisibility(View.GONE);
                }
            }
        }
    };

    TimerTask task = new TimerTask() {
        @Override
        public void run() {
            recLen--;
            Message message = new Message();
            message.what = 1;
            handler.sendMessage(message);
        }
    };
}
方法三
Handler与Message（不用TimerTask）

public class timerTask extends Activity{
    private int recLen = 11;
    private TextView txtView;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.timertask);
        txtView = (TextView)findViewById(R.id.txttime);

        Message message = handler.obtainMessage(1);     // Message
        handler.sendMessageDelayed(message, 1000);
    }

    final Handler handler = new Handler(){

        public void handleMessage(Message msg){         // handle message
            switch (msg.what) {
            case 1:
                recLen--;
                txtView.setText("" + recLen);

                if(recLen > 0){
                    Message message = handler.obtainMessage(1);
                    handler.sendMessageDelayed(message, 1000);      // send message
                }else{
                    txtView.setVisibility(View.GONE);
                }
            }

            super.handleMessage(msg);
        }
    };
}

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