Android OTP页面如何实现仅显秒数的倒计时及重发按钮灰化效果

修复点说明 #

• 调整倒计时显示逻辑，仅展示剩余秒数，移除多余前缀文字
• 保留重发按钮全程可见，禁用状态下自动灰化（Android原生Button特性，无需额外配置，只要不主动设置隐藏属性即可）
• 补充OTP全部输入完成后自动停止倒计时的逻辑

核心代码修改 #

Java代码（OTPActivity.java） #

public class OTPActivity extends AppCompatActivity implements  AdapterView.OnItemSelectedListener{
    private EditText editText1, editText2, editText3, editText4;
    private EditText[] editTexts;
    CountDownTimer cTimer = null;
    TextView tv;
    Button resend;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_otpactivity2);

        tv = (TextView) findViewById(R.id.timer);
        resend = (Button) findViewById(R.id.ResendOTP);
        editText1 = (EditText) findViewById(R.id.otpEdit1);
        editText2 = (EditText) findViewById(R.id.otpEdit2);
        editText3 = (EditText) findViewById(R.id.otpEdit3);
        editText4 = (EditText) findViewById(R.id.otpEdit4);
        editTexts = new EditText[]{editText1, editText2, editText3, editText4};

        editText1.addTextChangedListener(new PinTextWatcher(0));
        editText2.addTextChangedListener(new PinTextWatcher(1));
        editText3.addTextChangedListener(new PinTextWatcher(2));
        editText4.addTextChangedListener(new PinTextWatcher(3));

        editText1.setOnKeyListener(new PinOnKeyListener(0));
        editText2.setOnKeyListener(new PinOnKeyListener(1));
        editText3.setOnKeyListener(new PinOnKeyListener(2));
        editText4.setOnKeyListener(new PinOnKeyListener(3));
        startTimer();
        resend.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startTimer();
            }
        });
    }
    void startTimer() {
        resend.setEnabled(false);
        cTimer = new CountDownTimer(30000, 1000) {
            public void onTick(long millisUntilFinished) {
                // 仅展示剩余秒数，移除多余文字
                tv.setText(String.valueOf(millisUntilFinished/1000));
            }
            public void onFinish() {
                tv.setText("");
                resend.setEnabled(true);
            }
        };
        cTimer.start();
    }


    //cancel timer
    void cancelTimer() {
        if(cTimer!=null)
            cTimer.cancel();
        // 倒计时取消后清空计时文本，恢复按钮可用
        tv.setText("");
        resend.setEnabled(true);
    }
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

    }

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

    }

    public class PinTextWatcher implements TextWatcher {

        private int currentIndex;
        private boolean isFirst = false, isLast = false;
        private String newTypedString = "";

        PinTextWatcher(int currentIndex) {
            this.currentIndex = currentIndex;

            if (currentIndex == 0)
                this.isFirst = true;
            else if (currentIndex == editTexts.length - 1)
                this.isLast = true;
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            newTypedString = s.subSequence(start, start + count).toString().trim();
        }

        @Override
        public void afterTextChanged(Editable s) {

            String text = newTypedString;

            /* Detect paste event and set first char */
            if (text.length() > 1)
                text = String.valueOf(text.charAt(0)); // TODO: We can fill out other EditTexts

            editTexts[currentIndex].removeTextChangedListener(this);
            editTexts[currentIndex].setText(text);
            editTexts[currentIndex].setSelection(text.length());
            editTexts[currentIndex].addTextChangedListener(this);

            if (text.length() == 1)
                moveToNext();
            else if (text.length() == 0)
                moveToPrevious();
        }

        private void moveToNext() {
            if (!isLast)
                editTexts[currentIndex + 1].requestFocus();

            if (isAllEditTextsFilled() && isLast) { // isLast is optional
                editTexts[currentIndex].clearFocus();
                hideKeyboard();
                // 所有OTP输入完成，停止倒计时
                cancelTimer();
            }
        }

        private void moveToPrevious() {
            if (!isFirst)
                editTexts[currentIndex - 1].requestFocus();
        }

        private boolean isAllEditTextsFilled() {
            for (EditText editText : editTexts)
                if (editText.getText().toString().trim().length() == 0)
                    return false;
            return true;
        }

        private void hideKeyboard() {
            if (getCurrentFocus() != null) {
                InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
                inputMethodManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
            }
        }

    }

    public class PinOnKeyListener implements View.OnKeyListener {

        private int currentIndex;

        PinOnKeyListener(int currentIndex) {
            this.currentIndex = currentIndex;
        }

        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (keyCode == KeyEvent.KEYCODE_DEL && event.getAction() == KeyEvent.ACTION_DOWN) {
                if (editTexts[currentIndex].getText().toString().isEmpty() && currentIndex != 0)
                    editTexts[currentIndex - 1].requestFocus();
            }
            return false;
        }

    }
}

XML布局代码（activity_otpactivity2.xml） #

现有布局无需修改，只要不主动设置按钮的visibility属性即可保持全程可见，Android原生Button在setEnabled(false)时会自动呈现灰化不可点击状态：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:gravity="center"
    android:layout_height="match_parent"
    >
    <androidx.cardview.widget.CardView
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:id="@+id/card_view"
        android:layout_width="180dp"
        card_view:cardElevation="4dp"
        android:gravity="center"
        android:layout_height="60dp"
        card_view:cardCornerRadius="4dp">
        <LinearLayout

            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:layout_gravity="center">
        <EditText
            android:id="@+id/otpEdit1"
            android:digits="1234567890"
            android:inputType="number"
            android:maxLength="1"
            android:gravity="center"
            android:layout_weight="1"
            android:layout_width="2dp"
            android:layout_height="wrap_content"
            />
        <EditText
            android:id="@+id/otpEdit2"
            android:digits="1234567890"
            android:inputType="number"
            android:maxLength="1"
            android:gravity="center"
            android:layout_weight="1"
            android:layout_width="2dp"
            android:layout_height="wrap_content"
        />
        <EditText
            android:id="@+id/otpEdit3"
            android:digits="1234567890"
            android:inputType="number"
            android:maxLength="1"
            android:gravity="center"
            android:layout_weight="1"
            android:layout_width="2dp"
            android:layout_height="wrap_content"
        />
        <EditText
            android:id="@+id/otpEdit4"
            android:digits="1234567890"
            android:inputType="number"
            android:maxLength="1"
            android:gravity="center"
            android:layout_weight="1"
            android:layout_width="2dp"
            android:layout_height="wrap_content"
        />
        </LinearLayout>
    </androidx.cardview.widget.CardView>
    <TextView
        android:id="@+id/timer"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Timer"
        android:layout_marginLeft="10dp"/>
    <Button
        android:id="@+id/ResendOTP"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ResendOTP" />
</LinearLayout>

内容的提问来源于stack exchange，提问作者laxmi narayan