在Android的开发中，我们经常遇见倒计时的操作，通常使用Timer和Handler共同操作来完成。当然也可以使用Android系统控件CountDownTimer，这里我们封装成一个控件，也方便大家的使用。 首先
在Android的开发中，我们经常遇见倒计时的操作，通常使用Timer和Handler共同操作来完成。当然也可以使用Android系统控件CountDownTimer，这里我们封装成一个控件，也方便大家的使用。
首先上一张效果图吧：
说一下造成卡顿的原因，由于滑动的时候，adapter的getView频繁的创建和销毁，就会出现卡顿和数据错位问题，那么我们每一个item的倒计时就需要单独维护，这里我用的Handler与timer及TimerTask结合的方法，我们知道TimerTask运行在自己子线程，然后通过Timer的schedule（）方法实现倒计时功能，最后通过Hander实现View的刷新，其核心代码如下：
public class CountDownView extends LinearLayout {
@BindView(R.id.tv_day)
TextView tvDay;
@BindView(R.id.tv_hour)
TextView tvHour;
@BindView(R.id.tv_minute)
TextView tvMinute;
@BindView(R.id.tv_second)
TextView tvSecond;
@BindView(R.id.day)
TextView day;
@BindView(R.id.hour)
TextView hour;
@BindView(R.id.minute)
TextView minute;
private Context context;
private int viewBg;//倒计时的背景
private int cellBg;//每个倒计时的背景
private int cellTextColor;//文字颜色
private int textColor;//外部：等颜色
private int textSize = 14;//外部文字大小
private int cellTextSize = 12;//cell文字大小
private TimerTask timerTask = null;
private Timer timer = new Timer();
private Handler handler = new Handler() {
public void handleMessage(Message msg) {
countDown();
}
};
public CountDownView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
this.context = context;
}
public CountDownView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.context = context;
initAttrs(attrs, defStyleAttr);
initView(context);
}
private void initAttrs(AttributeSet attrs, int defStyle) {
TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.CountDownView, defStyle,0);
viewBg = typedArray.getColor(R.styleable.CountDownView_viewBg, Color.parseColor("#FFFFFF"));
cellBg = typedArray.getColor(R.styleable.CountDownView_cellBg, Color.parseColor("#F4F4F4"));
cellTextColor = typedArray.getColor(R.styleable.CountDownView_cellTextColor, Color.parseColor("#646464"));
textColor = typedArray.getColor(R.styleable.CountDownView_TextColor, Color.parseColor("#B3B3B3"));
textSize = (int) typedArray.getDimension(R.styleable.CountDownView_TextSize, UIUtils.dp2px(getContext(), 14));
cellTextSize = (int) typedArray.getDimension(R.styleable.CountDownView_cellTextSize, UIUtils.dp2px(getContext(), 12));
typedArray.recycle();
}
private void initView(Context context) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.layout_countdown_layout, this);
ButterKnife.bind(view);
initProperty();
}
private void initProperty() {
tvDay.setBackgroundColor(cellBg);
tvHour.setBackgroundColor(cellBg);
tvMinute.setBackgroundColor(cellBg);
tvSecond.setBackgroundColor(cellBg);
tvDay.setTextColor(cellTextColor);
tvHour.setTextColor(cellTextColor);
tvMinute.setTextColor(cellTextColor);
tvSecond.setTextColor(cellTextColor);
day.setTextColor(textColor);
hour.setTextColor(textColor);
minute.setTextColor(textColor);
}
public void setLeftTime(long leftTime) {
if (leftTime <= 0) return;
long time = leftTime / 1000;
long day = time / (3600 * 24);
long hours = (time - day * 3600 * 24) / 3600;
long minutes = (time - day * 3600 * 24 - hours * 3600) / 60;
long seconds = time - day * 3600 * 24 - hours * 3600 - minutes * 60;
setTextTime(time);
}
public void start() {
if (timerTask == null) {
timerTask = new TimerTask() {
@Override
public void run() {
handler.sendEmptyMessage(0);
}
};
timer.schedule(timerTask, 1000, 1000);
// timer.schedule(new TimerTask() {
// @Override
// public void run() {
// handler.sendEmptyMessage(0);
// }
// }, 0, 1000);
}
}
public void stop() {
if (timer != null) {
timer.cancel();
timer = null;
}
}
//保证天，时，分，秒都两位显示，不足的补0
private void setTextTime(long time) {
String[] s = TimeUtils.formatTimer(time);
tvDay.setText(s[0]);
tvHour.setText(s[1]);
tvMinute.setText(s[2]);
tvSecond.setText(s[3]);
}
private void countDown() {
if (isCarry4Unit(tvSecond)) {
if (isCarry4Unit(tvMinute)) {
if (isCarry4Unit(tvHour)) {
if (isCarry4Unit(tvDay)) {
stop();
}
}
}
}
}
private boolean isCarry4Unit(TextView tv) {
int time = Integer.valueOf(tv.getText().toString());
time = time - 1;
if (time < 0) {
time = 59;
tv.setText(time + "");
return true;
} else if (time < 10) {
tv.setText("0" + time);
return false;
} else {
tv.setText(time + "");
return false;
}
}
}
另一种写法：
public class CountDownTimerView extends LinearLayout {
private TextView hourView, minuteView, secondView;
private LimitTimer mTimer;
private Handler handler;
public static final int START_LIMIT_TIME_MSG = 0x0111;
public static final int END_LIMIT_TIME_MSG = 0x0112;
private long endTime, leftTime;
private LimitTimeListener listener=null;
public CountDownTimerView(Context context) {
super(context);
initView(context);
}
public CountDownTimerView(Context context, AttributeSet attrs) {
super(context, attrs);
initView(context);
}
private void initView(Context context) {
setOrientation(HORIZONTAL);
setGravity(Gravity.CENTER_VERTICAL);
inflate(context, R.layout.layout_countdown_layout, this);
hourView = (TextView) findViewById(R.id.tv_hour);
minuteView = (TextView) findViewById(R.id.tv_minute);
secondView = (TextView) findViewById(R.id.tv_second);
}
public long getLeftTime() {
return leftTime;
}
//设置剩余时间
public void initLeftTime(long endTime) {
endTime=endTime*1000;
if (null != mTimer) {
mTimer.cancel();
mTimer = null;
}
this.endTime = endTime;
mTimer = new LimitTimer(endTime, 1000);
mTimer.start();
if (handler != null) {
handler.sendEmptyMessage(START_LIMIT_TIME_MSG);
}
}
/**
* 如果该控件使用在碎片中，返回时，则最好还是要stop
*/
public void stopTimeCount() {
if (null != mTimer) {
mTimer.cancel();
mTimer = null;
}
}
public Handler getHandler() {
return handler;
}
public void setHandler(Handler handler) {
this.handler = handler;
}
private class LimitTimer extends CountDownTimer {
public LimitTimer(long millisInFuture, long countDownInterval) {
super(0 != leftTime ? leftTime : endTime, countDownInterval);
}
@Override
public void onTick(long millisUntilFinished) {
leftTime = millisUntilFinished;
long totalSecond = millisUntilFinished / 1000;
int second = (int) (totalSecond % 60);
int minute = (int) ((totalSecond / 60) % 60);
int hour = (int) ((totalSecond / 3600) % 24);
int day = (int) (totalSecond / (3600 * 24));
formatView(hourView, hour);
formatView(minuteView, minute);
formatView(secondView, second);
}
@Override
public void onFinish() {
String zero = "00";
hourView.setText(zero);
minuteView.setText(zero);
secondView.setText(zero);
if (null != handler) {
handler.sendEmptyMessage(END_LIMIT_TIME_MSG);
}
if (listener!=null){
listener.onTimeOver(true);
}
}
private void formatView(TextView view, int time) {
DecimalFormat df = new DecimalFormat("#00");
view.setText(df.format(time));
}
}
//倒计时结束监听
public void setOnLimitTimeListener(LimitTimeListener listener) {
this.listener = listener;
}
public interface LimitTimeListener {
void onTimeOver(boolean flag);
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
if (handler != null) {
handler.removeMessages(START_LIMIT_TIME_MSG);
}
}
}
涉及到的布局文件
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal"> <TextView android:id="@+id/tv_hour" style="@style/style_countdown" /> <TextView style="@style/style_wrap_content" android:layout_marginLeft="3dp" android:layout_marginRight="3dp" android:layout_gravity="center_vertical" android:text="时" android:textColor="@color/color_646464" /> <TextView android:id="@+id/tv_minute" style="@style/style_countdown" /> <TextView style="@style/style_wrap_content" android:layout_marginLeft="3dp" android:layout_marginRight="3dp" android:layout_gravity="center_vertical" android:text="分" android:textColor="@color/color_646464" /> <TextView android:id="@+id/tv_second" style="@style/style_countdown" /> <TextView style="@style/style_wrap_content" android:layout_marginLeft="3dp" android:layout_marginRight="3dp" android:layout_gravity="center_vertical" android:text="秒" android:textColor="@color/color_646464" /> </LinearLayout>
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