我想为我的Android程序实现一个java倒计时器，但我不知道该怎么做。它应该计算从让我们说60到0的时间，最后程序应该结束，但用户需要查看剩余的时间，因此计时器应该始终可见。我设法实现了一个“计时器”，游戏接受输入的时间有多长，但我不明白我应该如何制作倒计时系统。这是我制作的程序的源文件。希望你们能事先帮助我，
package com.example.mathcalcplus;
import java.util.Random;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
public class PlayGame extends Activity implements OnClickListener {
ImageView image;
TextView question, answer, score, timeLeft;
int difLevel, operator1, operator2, finalAnswer=0, operation, scoreCount = 0, userAnswer=0;
final private int add = 0, sub = 1, div = 3, mul = 2;
String[] getOperation = { "+", "-", "*", "/"};
Button btn1, btn2, btn3, btn4, btn5, btn6, btn7, btn8, btn9, btn0, btnClear, btnEnter;
Random rand;
String getQuestion, userInput;
long start;
long end;
boolean running = true;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.play_game);
btn1 = (Button) findViewById(R.id.btn1);
btn2 = (Button) findViewById(R.id.btn2);
btn3 = (Button) findViewById(R.id.btn3);
btn4 = (Button) findViewById(R.id.btn4);
btn5 = (Button) findViewById(R.id.btn5);
btn6 = (Button) findViewById(R.id.btn6);
btn7 = (Button) findViewById(R.id.btn7);
btn8 = (Button) findViewById(R.id.btn8);
btn9 = (Button) findViewById(R.id.btn9);
btn0 = (Button) findViewById(R.id.btn0);
btnClear = (Button) findViewById(R.id.clear);
btnEnter = (Button) findViewById(R.id.enter);
question = (TextView) findViewById(R.id.question);
answer = (TextView) findViewById(R.id.answer);
score = (TextView) findViewById(R.id.score);
image = (ImageView) findViewById(R.id.response);
timeLeft = (TextView) findViewById(R.id.timeLeft);
btn1.setOnClickListener(this);
btn2.setOnClickListener(this);
btn3.setOnClickListener(this);
btn4.setOnClickListener(this);
btn5.setOnClickListener(this);
btn6.setOnClickListener(this);
btn7.setOnClickListener(this);
btn8.setOnClickListener(this);
btn9.setOnClickListener(this);
btn0.setOnClickListener(this);
btnClear.setOnClickListener(this);
btnEnter.setOnClickListener(this);
rand = new Random();
Bundle extras = getIntent().getExtras();
if(extras != null)
{
int passedLevel = extras.getInt("level", -1);
if(passedLevel>=0) difLevel = passedLevel;
}
image.setVisibility(View.INVISIBLE);
choseQuestion();
start = System.currentTimeMillis();
end = start + 30*1000;
}
public void run(){
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.enter:
String getUserAnswer = answer.getText().toString();
if (!getUserAnswer.endsWith("?")){
userAnswer = Integer.parseInt(getUserAnswer.substring(1));
if (userAnswer == finalAnswer){
scoreCount++;
score.setText("Score=" + " " + scoreCount);
image.setImageResource(R.drawable.tick);
image.setVisibility(View.VISIBLE);
}
else{
scoreCount = 0;
score.setText("Score=" + " " + scoreCount);
image.setImageResource(R.drawable.cross);
image.setVisibility(View.VISIBLE);
}
finalAnswer =0;
choseQuestion();
getUserAnswer = "";
userAnswer = 0;
break;
}
else{
break;
}
case R.id.clear:
answer.setText("=?");
break;
default:
if (System.currentTimeMillis() < end){
int enteredNum = Integer.parseInt(v.getTag().toString());
if(answer.getText().toString().endsWith("?"))
answer.setText("="+enteredNum);
else
answer.append(""+enteredNum);
}
}
}
private void choseQuestion() {
answer.setText("=?");
operation = rand.nextInt(getOperation.length);
operator1 = getNumbers();
operator2 = getNumbers();
if (operation == sub){
while (operator2 > operator1){
operator1 = getNumbers();
operator2 = getNumbers();
}
}
if (operation == div){
while((double)operator1%(double)operator2 > 0 || (operator2 > operator1)){
operator1 = getNumbers();
operator2 = getNumbers();
}
}
switch(operation){
case add:
finalAnswer = operator1 + operator2;
break;
case sub:
finalAnswer = operator1 - operator2;
break;
case div:
finalAnswer = operator1 / operator2;
break;
case mul:
finalAnswer = operator1 * operator2;
break;
}
question.setText(operator1 + getOperation[operation] +operator2);
timeLeft.setText("Time :" + end);
}
private int getNumbers(){
int n = rand.nextInt(100) + 1;`enter code here`
return n;
}
}
答案 0 :(得分：2)
CountDownTimer，并以毫秒为单位设置时间范围。调用countDown方法，您的CountDownTimer已准备就绪！
private final static int time = 10000;
private CountDownTimer timerCount;
public void countDown(){
countDown = (TextView) findViewById(R.id.countdown);
timerCount = new CountDownTimer(time, 1000) {
public void onTick(long millisUntilFinished) {
long tmp = millisUntilFinished / 1000;
countDown.setText(tmp + "");
}
public void onFinish() {
// Do your stuff
countDown.setText("0");
}
}.start();
}
您的 .xml文件
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/questionList"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/menu"
android:orientation="vertical"
android:weightSum="4" >
<TextView
android:id="@+id/title"
android:layout_gravity="center"
android:layout_width="wrap_content"
android:textSize="14sp"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/countdown"
android:layout_gravity="right"
android:layout_width="30dp"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="numberDecimal" >
<requestFocus />
</TextView>
答案 1 :(得分：1)
new CountDownTimer(60000, 1000) {
public void onTick(long millisUntilFinished) {
mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
//here you can have your logic to set text to edittext
}
public void onFinish() {
mTextField.setText("done!");
}
}.start();
这是example。
请参阅此link了解倒计时器。