如何创建一个可以 select 倒计时的微调器

Question

我正在创建一个锻炼应用程序，我到处搜索以尝试找到如何创建一个显示持续时间的微调器，当用户选择持续时间时，所选时间将显示在另一个 activity 中的倒数计时器。感谢您的帮助！

Answer 1

创建一个包含所需值的数组，将其显示在微调器中，并通过有关所选数字的回调通知感兴趣的 class。在那里你应该实现处理数字的逻辑。您的问题太宽泛，无法更详细地回答。

Answer 2

您需要在 XML 中创建一个字符串数组：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="planets_array">
        <item>Mercury</item>
        <item>Venus</item>
        <item>Earth</item>
        <item>Mars</item>
        <item>Jupiter</item>
        <item>Saturn</item>
        <item>Uranus</item>
        <item>Neptune</item>
    </string-array>
</resources>

之后，使用适配器将数组设置为 Spinner：

Spinner spinner = (Spinner) findViewById(R.id.spinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
    R.array.planets_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);

显然，不是行星，而是时间。

更多信息here。

Answer 3

希望这段代码能帮助您得到您想要的东西

在您的第一个 activity 中初始化微调器

public class MainActivity extends AppCompatActivity {

//Declare the ui component
private Spinner spinner;

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

    //initialize the ui component
    spinner = (Spinner) findViewById(R.id.spinner);

    //create a collection holding your desired time with a note first, we will check that later
    // to find if the user selects a time

    ArrayList<String> timer = new ArrayList<>();
    timer.add("Select your time");
    timer.add("10");
    timer.add("20");
    timer.add("30");
    timer.add("40");

    //create a adpter for the spinner and set that to the spinner
    ArrayAdapter<String> spinnerAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, timer);
    spinner.setAdapter(spinnerAdapter);


    // create a onItemSelectedListener to get the user input from spinner
    spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
            //get the selected text from spinner
            String spinnerText = spinner.getSelectedItem().toString();


            //if the value is not "Select your time" then send them to another activity with intent
            if (!spinnerText.contentEquals("Select your time")) {

                Intent intent = new Intent(MainActivity.this, CountDownActivity.class);
                intent.putExtra("time", spinnerText);
                startActivity(intent);
            }
        }

        @Override
        public void onNothingSelected(AdapterView<?> adapterView) {

        }
    });
}

和另一个activity

public class CountDownActivity extends AppCompatActivity {
TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_count_down);

    //initialize the ui component
    textView = (TextView) findViewById(R.id.timeText);

    //get the text from intent
    String timerText = getIntent().getStringExtra("time");
    Toast.makeText(CountDownActivity.this, timerText, Toast.LENGTH_SHORT).show();

    //convert the string into integer
    int time = Integer.valueOf(timerText);

    //Initialize a CountDownTimer class with the time data from previous activity
    //which will set the text view with countDown time

    new CountDownTimer(time * 1000, 1000) {
        public void onTick(long millisUntilFinished) {
            //set the remaining time in the textView
            textView.setText("seconds remaining: " + millisUntilFinished / 1000);
        }

        public void onFinish() {
            textView.setText("done!");
        }
    }.start();
}

}

如果您在理解上有任何问题，或者这不能满足您的要求，请不要犹豫回复。快乐编码！！！

如何创建一个可以 select 倒计时的微调器

How to create a spinner that one can select a time to countdown from

java

android

timer

spinner