Android Studio中使用CountDownTimer的计时器

Question

请参阅我正在尝试获取时间的用户输入，并使用用户输入尝试在Android studio 4.2.2 中运行CountDownTimer功能

问题是：-

案例1

当我传递Variable name来代替countDown计时器函数的millisInFuture属性并尝试相应地设置textview时，textview不会得到任何设置。

public void timer() {
CountDownTimer countDownTimer = new CountDownTimer(**timeValueIntent**, 1000) {
@Override
public void onTick(long millisUntilFinished) {
//  mediaPlayer.setLooping(true);
//mediaPlayer.start();
timerValueTextView.setText(String.valueOf(millisUntilFinished / 1000) + "s");
}
@Override
public void onFinish() {
Toast.makeText(getApplicationContext(), "Timed out", Toast.LENGTH_SHORT).show();
restartButton.setVisibility(View.VISIBLE);
restartButton.setEnabled(true);
quitButton.setVisibility(View.VISIBLE);
setBtnCond(true);
//mediaPlayer.stop();
}
}.start();
}`

案例2

但是当我传递CountDownTimer的int值，如1000等(以毫秒为单位(，并设置textView时，它会成功设置

public void timer() {
CountDownTimer countDownTimer = new CountDownTimer(**300000**, 1000) {
@Override
public void onTick(long millisUntilFinished) {
//  mediaPlayer.setLooping(true);
//mediaPlayer.start();
timerValueTextView.setText(String.valueOf(millisUntilFinished / 1000) + "s");
}
@Override
public void onFinish() {
Toast.makeText(getApplicationContext(), "Timed out", Toast.LENGTH_SHORT).show();
restartButton.setVisibility(View.VISIBLE);
restartButton.setEnabled(true);
quitButton.setVisibility(View.VISIBLE);
setBtnCond(true);
//mediaPlayer.stop();
}
}.start();
}`

请的任何人帮助我在CountDownTimer函数的MillisInFuture属性中传递变量名，而不是硬编码的整数值。！！？`

Answer 1

我有一些与您的问题类似的源代码，只是实现您的项目。

初始化变量

private static final long START_TIME_IN_MILLIS = 600000;
private TextView mTextViewCountDown;
private Button mButtonStartPause;
private Button mButtonReset;
private CountDownTimer mCountDownTimer;
private boolean mTimerRunning;
private long mTimeLeftInMillis = START_TIME_IN_MILLIS;

onCreate

//Init
mTextViewCountDown = findViewById(R.id.text_view_countdown);
mButtonStartPause = findViewById(R.id.button_start_pause);
mButtonReset = findViewById(R.id.button_reset);
mButtonStartPause.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mTimerRunning) {
pauseTimer();       //pauseFunction
} else {
startTimer();       //StartFunction
}
}
});

mButtonReset.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
resetTimer();       // resetFunction
}
});
updateCountDownText();      //updateEverySecond

startTimer((

mCountDownTimer = new CountDownTimer(mTimeLeftInMillis, 1000) {
@Override
public void onTick(long millisUntilFinished) {
mTimeLeftInMillis = millisUntilFinished;
updateCountDownText();
}
@Override
public void onFinish() {
mTimerRunning = false;
mButtonStartPause.setText("Start");
mButtonStartPause.setVisibility(View.INVISIBLE);
mButtonReset.setVisibility(View.VISIBLE);
}
}.start();
mTimerRunning = true;
mButtonStartPause.setText("pause");
mButtonReset.setVisibility(View.INVISIBLE);

pauseTime((

mCountDownTimer.cancel();
mTimerRunning = false;
mButtonStartPause.setText("Start");
mButtonReset.setVisibility(View.VISIBLE);

resetTimer((

mTimeLeftInMillis = START_TIME_IN_MILLIS;
updateCountDownText();
mButtonReset.setVisibility(View.INVISIBLE);
mButtonStartPause.setVisibility(View.VISIBLE);

updateCountDownText((

int minutes = (int) (mTimeLeftInMillis / 1000) / 60;
int seconds = (int) (mTimeLeftInMillis / 1000) % 60;
String timeLeftFormatted = String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds);
mTextViewCountDown.setText(timeLeftFormatted);

最后XML

<TextView
android:id="@+id/text_view_countdown"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="00:00"
android:textColor="@android:color/black"
android:textSize="60sp" />
<Button
android:id="@+id/button_start_pause"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/text_view_countdown"
android:layout_centerHorizontal="true"
android:text="start" />
<Button
android:id="@+id/button_reset"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/text_view_countdown"
android:layout_marginStart="11dp"
android:layout_toEndOf="@+id/button_start_pause"
android:text="reset"
android:visibility="invisible"
tools:visibility="visible" />