如圖: 
主要的倒計時代碼如下....從秒判斷起...再判斷分...小時...
/** * 倒計時計算 */ PRivate void computeTime() { mSecond--; if (mSecond < 0) { mMin--; mSecond = 59; if (mMin < 0) { mMin = 59; mHour--; if (mHour < 0) { // 倒計時結束 mHour = 23; mDay--; if(mDay < 0){ // 倒計時結束 mDay = 0; mHour= 0; mMin = 0; mSecond = 0; } } } } }定時器主要代碼如下...當然也可以開線程或者開后臺服務來處理...只是沒那種必要...定時器就可以搞定容易控制...畢竟倒計時時間起點...你總得后臺獲取吧,不是做時鐘鬧鐘...如果是做時鐘鬧鐘...拿你也不用考慮后臺服務或者自己開現場...而是使用AlarmManager來實現
/** * 開啟倒計時 * //time為Date類型:在指定時間執行一次。 * timer.schedule(task, time); * //firstTime為Date類型,period為long,表示從firstTime時刻開始,每隔period毫秒執行一次。 * timer.schedule(task, firstTime,period); * //delay 為long類型:從現在起過delay毫秒執行一次。 * timer.schedule(task, delay); * //delay為long,period為long:從現在起過delay毫秒以后,每隔period毫秒執行一次。 * timer.schedule(task, delay,period); */ private void startRun() { TimerTask mTimerTask = new TimerTask() { @Override public void run() { Message message = Message.obtain(); message.what = 1; timeHandler.sendMessage(message); } }; mTimer.schedule(mTimerTask,0,1000); }修改界面,利用handler來提醒更新界面private Handler timeHandler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(msg); if (msg.what == 1) { computeTime(); mDays_Tv.setText(mDay+"");//天數不用補位 mHours_Tv.setText(getTv(mHour)); mMinutes_Tv.setText(getTv(mMin)); mSeconds_Tv.setText(getTv(mSecond)); if (mSecond == 0 && mDay == 0 && mHour == 0 && mMin == 0 ) { mTimer.cancel(); } } } }; private String getTv(long l){ if(l>=10){ return l+""; }else{ return "0"+l;//小于10,,前面補位一個"0" } }附帶主activity的代碼...import android.os.Handler;import android.os.Message;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.RelativeLayout;import android.widget.TextView;import java.util.Timer;import java.util.TimerTask;public class MainActivity extends AppCompatActivity { private RelativeLayout countDown; // 倒計時 private TextView mDays_Tv, mHours_Tv, mMinutes_Tv, mSeconds_Tv; private long mDay = 23;// 天 private long mHour = 11;//小時, private long mMin = 56;//分鐘, private long mSecond = 32;//秒 private Timer mTimer; private Handler timeHandler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(msg); if (msg.what == 1) { computeTime(); mDays_Tv.setText(mDay+"");//天數不用補位 mHours_Tv.setText(getTv(mHour)); mMinutes_Tv.setText(getTv(mMin)); mSeconds_Tv.setText(getTv(mSecond)); if (mSecond == 0 && mDay == 0 && mHour == 0 && mMin == 0 ) { mTimer.cancel(); } } } }; private String getTv(long l){ if(l>=10){ return l+""; }else{ return "0"+l;//小于10,,前面補位一個"0" } } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mTimer = new Timer(); countDown = (RelativeLayout) findViewById(R.id.countdown_layout); mDays_Tv = (TextView) findViewById(R.id.days_tv); mHours_Tv = (TextView) findViewById(R.id.hours_tv); mMinutes_Tv = (TextView) findViewById(R.id.minutes_tv); mSeconds_Tv = (TextView) findViewById(R.id.seconds_tv); startRun(); } /** * 開啟倒計時 * //time為Date類型:在指定時間執行一次。 * timer.schedule(task, time); * //firstTime為Date類型,period為long,表示從firstTime時刻開始,每隔period毫秒執行一次。 * timer.schedule(task, firstTime,period); * //delay 為long類型:從現在起過delay毫秒執行一次。 * timer.schedule(task, delay); * //delay為long,period為long:從現在起過delay毫秒以后,每隔period毫秒執行一次。 * timer.schedule(task, delay,period); */ private void startRun() { TimerTask mTimerTask = new TimerTask() { @Override public void run() { Message message = Message.obtain(); message.what = 1; timeHandler.sendMessage(message); } }; mTimer.schedule(mTimerTask,0,1000); } /** * 倒計時計算 */ private void computeTime() { mSecond--; if (mSecond < 0) { mMin--; mSecond = 59; if (mMin < 0) { mMin = 59; mHour--; if (mHour < 0) { // 倒計時結束 mHour = 23; mDay--; if(mDay < 0){ // 倒計時結束 mDay = 0; mHour= 0; mMin = 0; mSecond = 0; } } } } }}附帶xml的代碼<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/countdown_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@android:color/white" android:gravity="center" > <RelativeLayout android:id="@+id/daojishi_rl" android:layout_width="match_parent" android:layout_height="40.0dip" android:layout_marginLeft="10.0dip" android:layout_marginRight="10.0dip" android:gravity="center" > <ImageView android:id="@+id/describe_iv" android:layout_width="40dp" android:layout_height="40dp" android:src="@mipmap/img" android:scaleType="fitXY" android:gravity="center_vertical" /> <TextView android:id="@+id/describe_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginRight="5.0dip" android:layout_toRightOf="@+id/describe_iv" android:text="距離開團還有" android:textSize="25sp" /> <TextView android:id="@+id/days_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:padding="4dp" android:layout_toRightOf="@+id/describe_tv" android:background="#c2c2c2" android:gravity="center" android:text="" android:textSize="20sp" /> <TextView android:id="@+id/colon0" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="5.0dip" android:layout_marginRight="3.0dip" android:layout_toRightOf="@+id/days_tv" android:text="天" android:textSize="20sp" android:textStyle="bold" /> </RelativeLayout> <RelativeLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/daojishi_rl" android:gravity="center_horizontal" > <TextView android:id="@+id/hours_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_toLeftOf="@+id/colon1" android:background="#c2c2c2" android:gravity="center" android:text="23" android:padding="3dp" android:textSize="20sp" /> <TextView android:id="@+id/colon1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="3.0dip" android:layout_marginRight="3.0dip" android:layout_toLeftOf="@+id/minutes_tv" android:text=":" android:textSize="20sp" android:textStyle="bold" /> <TextView android:id="@+id/minutes_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_toLeftOf="@+id/colon2" android:background="#c2c2c2" android:gravity="center" android:text="59" android:padding="3dp" android:textSize="20sp" /> <TextView android:id="@+id/colon2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="3.0dip" android:layout_marginRight="3.0dip" android:layout_toLeftOf="@+id/seconds_tv" android:text=":" android:textSize="20sp" android:textStyle="bold" /> <TextView android:id="@+id/seconds_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_centerVertical="true" android:background="#c2c2c2" android:gravity="center" android:text="59" android:padding="3dp" android:textSize="20sp" /> </RelativeLayout></RelativeLayout>好了....倒計時完美實現
新聞熱點
疑難解答