Java 希望创建一个通用变量（我希望这是正确的术语）

我希望作出一些改变，这样我就不必重复我的代码（有意义）

以下是我目前的情况：

package com.rcd.learningactivities;

import java.text.DecimalFormat;
import java.util.concurrent.TimeUnit;

import android.app.Activity;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        final TextView blueTimer = (TextView) findViewById(R.id.blueTimer);  
        Button blue = (Button) findViewById(R.id.button1);

        final TextView redTimer = (TextView) findViewById(R.id.redTimer);  
        Button red = (Button) findViewById(R.id.button2);



        final CountDownTimer cd = new CountDownTimer(300000, 1000) {

             public void onTick(long millisUntilFinished) {
                    DecimalFormat dfmin = new DecimalFormat("0");
                    DecimalFormat dfsec = new DecimalFormat("00");
                    double seconds = TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished)%60;
                    double min = TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished);
                    blueTimer.setText(String.valueOf(dfmin.format(min)) + ":" + String.valueOf(dfsec.format(seconds)));

             }

             public void onFinish() {
                 blueTimer.setText("5:00");
             }
          };

        blue.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (blueTimer.getText().toString().contains("5:00")){
                    cd.start();

                } else {
                    cd.cancel();
                    cd.onFinish();
                }

            }
        });

        red.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (redTimer.getText().toString().contains("5:00")){
                    cd.start();
                } else {
                    cd.cancel();
                    cd.onFinish();
                }

            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

我希望blue.setOnClickListener和red.setOnClickListener都能够利用我的cd倒计时，但是我需要blueTimer.setText（字符串…）能够根据用户单击的按钮更改为redTimer.setText（字符串…）

我真的希望这是有意义的，如果我想这个倒退，请让我知道

---

基本上，我想在上面的onTick方法中创建blueTimer，变量x。

重点是使用类字段或属性：

    public class MainActivity extends Activity {
    protected CountDownTimer cd;
    private Button lastPressedButton;
    private Button red;
    private Button blue;
    private TextView blueTimer;
    private TextView redTimer;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);


            blueTimer = (TextView) findViewById(R.id.blueTimer);  
            blue = (Button) findViewById(R.id.button1);

            redTimer = (TextView) findViewById(R.id.redTimer);  
            red = (Button) findViewById(R.id.button2);



            cd = new CountDownTimer(300000, 1000) {

                 public void onTick(long millisUntilFinished) {
                        DecimalFormat dfmin = new DecimalFormat("0");
                        DecimalFormat dfsec = new DecimalFormat("00");
                        double seconds = TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished)%60;
                        double min = TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished);
if (lastPressedButton == red){
                 redTimer.setText(String.valueOf(dfmin.format(min)) + ":" + String.valueOf(dfsec.format(seconds)));
}
else if (lastPressedButton == blue){
                 blueTimer.setText(String.valueOf(dfmin.format(min)) + ":" + String.valueOf(dfsec.format(seconds)));
}


                 }

                 public void onFinish() {
    if (lastPressedButton == red)
                     blueTimer.setText("5:00");
    else if (lastPressedButton == blue){
    //something else?
    }
                 }
              };

            blue.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
    lastPressedButton = blue;
                    if (blueTimer.getText().toString().contains("5:00")){
                        cd.start();

                    } else {
                        cd.cancel();
                        cd.onFinish();
                    }

                }
            });

            red.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
    lastPressedButton = red;
                    if (redTimer.getText().toString().contains("5:00")){
                        cd.start();
                    } else {
                        cd.cancel();
                        cd.onFinish();
                    }

                }
            });
        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.main, menu);
            return true;
        }

    }

---

最简单的答案是设置要在计时器中更新的

TextView

，然后启动计时器。这需要您使用自己的类扩展

倒计时程序

：

public class MyCountDownTimer extends CountDownTimer {

    private TextView viewToUpdate; 

    public void onTick(long millisUntilFinished) {
        DecimalFormat dfmin = new DecimalFormat("0");
        DecimalFormat dfsec = new DecimalFormat("00");
        double seconds = TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished)%60;
        double min = TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished);

        // Make sure a view has been set
        if (viewToUpdate != null) {
            viewToUpdate.setText(String.valueOf(dfmin.format(min)) + ":" + 
                                 String.valueOf(dfsec.format(seconds)));
        }   
     }

     public void onFinish() {
         if (viewToUpdate != null) {
             viewToUpdate.setText("5:00");
         }
     }

     public void setViewToUpdate(TextView v)
     {
         viewToUpdate = v;
     }
}

---

现在，您可以使用它来代替倒计时，在单击侦听器中，您可以在调用

start（）

之前调用

setViewToUpdate（）

，我的答案引发异常，您是对的。我删除了我的答案，因为你的答案更能说明问题。除了。。。这与他问的问题无关。谢谢你，这个答案对我来说很有意义，我现在已经开始工作了！这是很可能有更好的答案，但因为我仍然是非常新的，这是最容易理解的！谢谢

public class MyCountDownTimer extends CountDownTimer {

    private TextView viewToUpdate; 

    public void onTick(long millisUntilFinished) {
        DecimalFormat dfmin = new DecimalFormat("0");
        DecimalFormat dfsec = new DecimalFormat("00");
        double seconds = TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished)%60;
        double min = TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished);

        // Make sure a view has been set
        if (viewToUpdate != null) {
            viewToUpdate.setText(String.valueOf(dfmin.format(min)) + ":" + 
                                 String.valueOf(dfsec.format(seconds)));
        }   
     }

     public void onFinish() {
         if (viewToUpdate != null) {
             viewToUpdate.setText("5:00");
         }
     }

     public void setViewToUpdate(TextView v)
     {
         viewToUpdate = v;
     }
}