如何通過按鈕啓動和停止我的倒計時器？

Question

這是我迄今爲止..它剛剛啓動時打開應用程序：

package com.android.countdown; 

import android.app.Activity; 
import android.os.Bundle; 
import android.os.CountDownTimer; 
import android.widget.TextView; 

public class countdown extends Activity { 

    TextView mTextField; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
     mTextField = (TextView) findViewById(R.id.timer1); 

     new CountDownTimer(100000, 1000) { 
      public void onTick(long millisUntilFinished) { 
       mTextField.setText("Seconds remaining: " + millisUntilFinished/1000); 
      } 

      public void onFinish() { 
       mTextField.setText("Finished"); 
      } 
     }.start(); 
    } 
} 

我知道，我需要調用start()按鈕過程內。但是，如果我將.start()從new CountDownTimer(100000 , 1000) {處獲取錯誤。

Answer 1

那麼......也許你需要先了解Java和編程如何工作。然後，你可以嘗試做這樣的事情：

CountDownTimer aCounter = new CountDownTimer(100000 , 1000) { 
    public void onTick(long millisUntilFinished) { 
     mTextField.setText("Seconds remaining: " + millisUntilFinished/1000); 
    } 

    public void onFinish() { 
     mTextField.setText("Finished"); 
    } 
}; 
aCounter.start(); 

Answer 2

你可以這樣做，做一個你想要的東西。下面是Java代碼：

package com.example.smartbroashad.countdowntimer; 

import android.os.CountDownTimer; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.TextView; 
import android.widget.Toast; 

public class MainActivity extends AppCompatActivity { 
TextView timing; 
TextView status; 
int workingornot=1; 
//running 

public void startmeplease(View view) 
{ 
    if (workingornot==1) 
    { 
     workingornot=2; 
     //runned 
     countDownTimerofme.start(); 
     Toast.makeText(this,"STARTED!",Toast.LENGTH_SHORT).show(); 
    } 
    else 
    { 
     Toast.makeText(this,"already started!",Toast.LENGTH_SHORT).show(); 
    } 

} 
public void stopmeplease(View view) 
{ 
    countDownTimerofme.cancel(); 
    status.setText("stoped!!"); 
    workingornot=1; 
} 
public void settimeplease(View view) 
{ 

} 
CountDownTimer countDownTimerofme=new CountDownTimer(10000,1000) { 
    @Override 
    public void onTick(long l) { 
     timing.setText("time left: "+toString().valueOf(l/1000)); 
     status.setText("started!!!"); 
    } 

    @Override 
    public void onFinish() { 
     timing.setText("time left: 0"); 
     status.setText("completed !!!!"); 
     workingornot=1;//now able to run again 


    } 
}; 


@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    timing=(TextView)findViewById(R.id.timer); 
    status=(TextView)findViewById(R.id.status); 
} 
} 

這裏是XML：

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout  xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:background=" #8e44ad" 
tools:context="com.example.smartbroashad.countdowntimer.MainActivity"> 

<TextView 
    android:id="@+id/status" 
    android:layout_width="wrap_content" 
    android:layout_height="133dp" 
    android:layout_marginBottom="69dp" 
    android:layout_marginTop="16dp" 
    android:padding="20sp" 
    android:text="@string/countdown_timer_not_running" 
    android:textAlignment="center" 
    android:textAllCaps="true" 
    android:textColor="#2c3e50" 
    android:textSize="32sp" 
    android:textStyle="bold" 
    app:layout_constraintBottom_toTopOf="@+id/linearLayout" 
    app:layout_constraintEnd_toEndOf="parent" 
    app:layout_constraintStart_toStartOf="parent" 
    app:layout_constraintTop_toTopOf="parent" /> 

<LinearLayout 
    android:id="@+id/linearLayout" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_marginBottom="61dp" 
    android:layout_marginTop="32dp" 
    android:orientation="vertical" 
    app:layout_constraintBottom_toTopOf="@+id/linearLayout2" 
    app:layout_constraintHorizontal_bias="1.0" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintRight_toRightOf="parent" 
    app:layout_constraintTop_toBottomOf="@+id/status"> 


    <EditText 
     android:id="@+id/editText7" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:ems="10" 
     android:inputType="time" /> 

    <Button 
     android:id="@+id/settime" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_weight="1" 
     android:background=" #00aced" 
     android:text="set time" 
     android:onClick="settimeplease" 
     android:textAlignment="center" 
     android:textAllCaps="true" 
     android:textColor="#2c3e50" 
     android:textSize="32sp" 
     android:textStyle="bold" /> 


</LinearLayout> 

<LinearLayout 
    android:id="@+id/linearLayout2" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_marginBottom="48dp" 
    android:layout_marginTop="32dp" 
    android:orientation="vertical" 
    app:layout_constraintBottom_toBottomOf="parent" 
    app:layout_constraintEnd_toEndOf="parent" 
    app:layout_constraintHorizontal_bias="0.0" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintRight_toRightOf="parent" 
    app:layout_constraintStart_toStartOf="parent" 
    app:layout_constraintTop_toBottomOf="@+id/linearLayout"> 

    <TextView 
     android:id="@+id/timer" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:text="@string/running" 

     android:textAlignment="center" 
     android:textAllCaps="true" 
     android:textColor="#2c3e50" 
     android:textSize="32sp" 
     android:textStyle="bold" 
     tools:text="@string/running" /> 

    <Button 
     android:id="@+id/start" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:background=" #64D448" 
     android:text="start" 
     android:onClick="startmeplease" 
     android:textAlignment="center" 
     android:textAllCaps="true" 
     android:textColor="#2c3e50" 
     android:textSize="32sp" 
     android:textStyle="bold" /> 

    <Button 
     android:id="@+id/stop" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:background=" #bb0000" 
     android:text="stop" 
     android:onClick="stopmeplease" 
     android:textAlignment="center" 
     android:textAllCaps="true" 
     android:textColor="#ffffff" 
     android:textSize="32sp" 
     android:textStyle="bold" /> 
</LinearLayout> 

</android.support.constraint.ConstraintLayout>