Android 迄今为止和下一个 activity 的倒数计时器？

Question

我有一个有 2 个 activity 的应用程序，所以我想在定时器结束时设置定时器，下一个 activity。我尝试了 5 秒钟，它成功了。但是当我尝试以天、小时、秒为单位计时但我做不到时，我遇到了一些问题。假设我设置这个时间 20.10.2019,10:00 AM 当这个设置时间结束时，它将进入下一个 activity.

如何做到这一点？有任何代码、资源或项目让我学习这件事吗？

Answer 1

你可以用一个Handler在一段时间后开始下一个activity，像这样

new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                final Intent intent = new Intent(FirstActivity.this, SecondActivity.class);                
                startActivity(intent);
            }
        },3000);

这将在 3000 毫秒或 3 秒后开始第二个 activity

Answer 2

更新，我试过了并且有效。

public class timer extends AppCompatActivity {
    /*Views declaration*/
    private TextView months_left,weeks_left,daysLeft,hrsLeft,minLeft,secLeft,endDate;
    /*Handler Declaration*/
    private Handler handler;
    /*set End Time for timer */
    private String endDateTime="2019-07-13 06:22:30";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_timer);



        initView();

    }
    private void initView() {
        months_left = findViewById(R.id.txtViewDays);
        weeks_left = findViewById(R.id.txtViewHours);
        daysLeft = findViewById(R.id.txtViewMinutes);
        hrsLeft = findViewById(R.id.txtViewSecond);
        minLeft = findViewById(R.id.misleft);
        secLeft = findViewById(R.id.seclft);
        endDate = findViewById(R.id.enddate);
        endDate.setText(endDateTime);
        /*invoke countDownStart() method for start count down*/
        countDownStart();
    }

    private void countDownStart() {

        handler = new Handler();
        Runnable runnable = new Runnable() {
            @SuppressLint("SetTextI18n")
            @Override
            public void run() {
                handler.postDelayed(this, 1000);
                try {
                    @SuppressLint("SimpleDateFormat") SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
                    // Please set date in  YYYY-MM-DD hh:mm:ss format
                    /*parse endDateTime in future date*/
                    Date futureDate = dateFormat.parse(endDateTime);
                    Date currentDate = new Date();
                    /*if current date is not comes after future date*/
                    if (!currentDate.after(futureDate)) {
                        long diff = futureDate.getTime()
                                - currentDate.getTime();

                        long days = diff / (24 * 60 * 60 * 1000);
                        diff -= days *(24  *60 * 60  *1000);
                        long hours = diff / (60 * 60*  1000);
                        diff -= hours * (60*  60 * 1000);
                        long minutes = diff / (60 * 1000);
                        diff -= minutes * (60  *1000);
                        long seconds = diff / 1000;
                        @SuppressLint("DefaultLocale") String dayLeft = "" + String.format("%02d", days);
                        @SuppressLint("DefaultLocale") String hrLeft = "" + String.format("%02d", hours);
                        @SuppressLint("DefaultLocale") String minsLeft = "" + String.format("%02d", minutes);
                        @SuppressLint("DefaultLocale") String secondLeft = "" + String.format("%02d", seconds);
                        daysLeft.setText(dayLeft + "D: ");
                        hrsLeft.setText(hrLeft + "H: ");
                        minLeft.setText(minsLeft + "M: ");
                        secLeft.setText(secondLeft + "S");
                        if (days <= 0) {
                            if (hours <= 0) {
                                if (minutes <= 0) {
                                    if (seconds <= 0) {
                                        // put your intent here
                                        myActivity();
                                    }
                                }
                            }
                        }

                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        };
        handler.postDelayed(runnable, 1000);
    }

    private void myActivity() {
        Intent myActivity= new Intent(timer.this, New.class);
        startActivity(myActivity);
    }
}

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