android - 简单的 Android 二进制文本时钟

Question

我想创建一个简单的 Android 二进制时钟，但我的应用程序崩溃了。 我使用 6 个 TextView 字段:3 个用于十进制表示，3 个用于当前时间的二进制表示形式 (HH:mm:ss)。 代码如下:

import java.text.SimpleDateFormat;
import java.util.Calendar;

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

public class Binary extends Activity implements Runnable
{
 Thread runner;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

  if (runner == null)
  { //start the song
   runner = new Thread(this);
   runner.start();
  }
    }

 @Override
 public void run()
 {
  TextView hours_dec = (TextView) findViewById(R.id.hours_dec);
  TextView mins_dec = (TextView) findViewById(R.id.mins_dec);
  TextView secs_dec = (TextView) findViewById(R.id.secs_dec);
  TextView hours_bin = (TextView) findViewById(R.id.hours_bin);
  TextView mins_bin = (TextView) findViewById(R.id.mins_bin);
  TextView secs_bin = (TextView) findViewById(R.id.secs_bin);

        SimpleDateFormat hours_sdf = new SimpleDateFormat("HH");
        SimpleDateFormat mins_sdf = new SimpleDateFormat("mm");
        SimpleDateFormat secs_sdf = new SimpleDateFormat("ss");

        Calendar cal = Calendar.getInstance();

  while (runner != null)
  {
   WaitAMoment();
   cal.getTime();

   hours_dec.setText(hours_sdf.format(cal.getTime()));
   mins_dec.setText(mins_sdf.format(cal.getTime()));
   secs_dec.setText(secs_sdf.format(cal.getTime()));

   hours_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) hours_dec.getText()))));
   mins_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) mins_dec.getText()))));
   secs_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) secs_dec.getText()))));
  }

 }

 protected void WaitAMoment()
 {
  try
  {
   Thread.sleep(100);
  } catch (InterruptedException e) { };
 }
}`

Answer 1

您正在尝试从另一个线程中更新您的 View 组件。您需要使用从第二个线程调用的处理程序将组件更新分离到 Runnable 对象中。

了解更多信息:https://developer.android.com/guide/appendix/faq/commontasks.html#threading

奖金代码:

package stackoverflow.test.binaryclock;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.widget.TextView;

public class BinaryClock extends Activity implements Runnable
{
    Date currentTime;
     Thread runner;
     final Runnable updater = new Runnable(){
        public void run(){
            updateClockValues();
        };
     };
     final Handler mHandler = new Handler();
    TextView hours_dec;
    TextView mins_dec;
    TextView secs_dec;
    TextView hours_bin;
    TextView mins_bin;
    TextView secs_bin;

    SimpleDateFormat hours_sdf = new SimpleDateFormat("HH");
    SimpleDateFormat mins_sdf = new SimpleDateFormat("mm");
    SimpleDateFormat secs_sdf = new SimpleDateFormat("ss");

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        currentTime = Calendar.getInstance().getTime();
        hours_dec = (TextView) findViewById(R.id.hours_dec);
        mins_dec = (TextView) findViewById(R.id.mins_dec);
        secs_dec = (TextView) findViewById(R.id.secs_dec);
        hours_bin = (TextView) findViewById(R.id.hours_bin);
        mins_bin = (TextView) findViewById(R.id.mins_bin);
        secs_bin = (TextView) findViewById(R.id.secs_bin);
        if (runner == null)
        { //start the song
           runner = new Thread(this);
           runner.start();
        }
      }

 private void updateClockValues() {
        currentTime = Calendar.getInstance().getTime();
        hours_dec.setText(hours_sdf.format(currentTime.getTime()));
        mins_dec.setText(mins_sdf.format(currentTime.getTime()));
        secs_dec.setText(secs_sdf.format(currentTime.getTime()));

        hours_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) hours_dec.getText()))));
        mins_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) mins_dec.getText()))));
        secs_bin.setText(String.valueOf(Integer.toBinaryString(Integer.parseInt((String) secs_dec.getText()))));
    }
@Override
 public void run()
 {
  while (runner != null)
  {
      try
      {
       Thread.sleep(1000);
       Log.i("Tick", "Tock");
      } catch (InterruptedException e) { };
      mHandler.post(updater);
     }
 }
}