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所有功能都运行正常，但只有一个问题存在，如果我记录一天的详细信息，并且如果我将选项卡切换到历史选项卡以查看新记录，则历史记录类中的视图列表应该显示该记录。但是视图列表不显示最新记录，我检查数据库，最新记录已写入数据库。查看新记录的唯一方法是关闭模拟器并重新启动它。

我发现在启动时，记录器和历史选项卡都会在 OnCreate() 方法中初始化的问题。但在那之后，当我在这两个选项卡之间切换时，它不会被初始化。因此，在history.class 中，它不会打开数据库并读取数据。那就是问题所在。有人可以帮我吗，谢谢

选项卡原型类

package com.example.tabpro;

import android.app.TabActivity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TabHost;
import android.widget.TabHost.OnTabChangeListener;
import android.widget.TabHost.TabSpec;

public class TabBar extends TabActivity{

static TabHost tabHost=null;
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.tab);

    tabHost = (TabHost)findViewById(android.R.id.tabhost);

    tabHost = getTabHost();
    Intent recorderIntent = new Intent(TabBar.this, Recorder.class);
    TabSpec recorderTabSpec = tabHost.newTabSpec("tab1");
    recorderTabSpec.setIndicator("Recorder");
    recorderTabSpec.setContent(recorderIntent);
    tabHost.addTab(recorderTabSpec);

    Intent historyIntent = new Intent(TabBar.this,History.class);
    TabSpec historyTabSpec = tabHost.newTabSpec("tab2");
    historyTabSpec.setIndicator("History");
    historyTabSpec.setContent(historyIntent);
    tabHost.addTab(historyTabSpec);

    tabHost.setCurrentTab(0);


}
public void switchTab(int tab)
{
    tabHost.setCurrentTab(tab);
}
}

记录器类

package com.example.tabpro;

import java.util.Calendar;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.DatePickerDialog.OnDateSetListener;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TabHost;
import android.widget.TextView;
import android.widget.Toast;

public class Recorder  extends Activity implements OnSeekBarChangeListener {


int mYear;
int mMonth;
int mDay;


TextView dateDisplay;
Button pickDateButton;

TextView sbHourValue;
TextView sbMinValue;

int hours;
int mins;

static final int DATE_DIALOG_ID = 0;  



public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.recorder);

    initialDatePicker();
    initialSeekBar();
    initialSaveButton();

}

public void initialDatePicker()
{
    dateDisplay = (TextView)findViewById(R.id.dateDisplay); 
    pickDateButton = (Button)findViewById(R.id.pickDate);
    pickDateButton.setOnClickListener(new OnClickListener() {  

      @Override  
      public void onClick(View v) {  
          showDialog(DATE_DIALOG_ID);  
      }  
  });  

  final Calendar currentDate = Calendar.getInstance();  
  mYear = currentDate.get(Calendar.YEAR);  
  mMonth = currentDate.get(Calendar.MONTH);  
  mDay = currentDate.get(Calendar.DAY_OF_MONTH);  
  dateDisplay.setText(new StringBuilder()  
              .append(mYear).append("-")  
              .append(mMonth + 1).append("-")
              .append(mDay)); 


}

public DatePickerDialog.OnDateSetListener mDateSetListener = new OnDateSetListener() {  
    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {  
        mYear = year;  
        mMonth = monthOfYear;  
        mDay = dayOfMonth;  

        dateDisplay.setText(new StringBuilder()  
                    .append(mYear).append("-")  
                    .append(mMonth + 1).append("-")//start from 0
                    .append(mDay));  
    }  
};

protected Dialog onCreateDialog(int id){
    switch(id)
    {
    case DATE_DIALOG_ID:  
        return new DatePickerDialog(this,mDateSetListener,mYear, mMonth, mDay); 
    }
    return null;
}



public void initialSeekBar()
{
    SeekBar sbHour = (SeekBar)findViewById(R.id.seekBar_hour);
    sbHour.setMax(23);
    sbHour.setProgress(0);
    sbHour.setOnSeekBarChangeListener(this);
    sbHourValue = (TextView)findViewById(R.id.textView_hour);
    sbHourValue.setText("0"+ " hour(s)");

    SeekBar sbMin = (SeekBar)findViewById(R.id.seekBar_min);
    sbMin.setMax(59);
    sbMin.setProgress(0);
    sbMin.setOnSeekBarChangeListener(this);
    sbMinValue = (TextView)findViewById(R.id.TextView_min);
    sbMinValue.setText("0" + " minute(s)");
}

public void initialSaveButton()
{

    Button saveButton = (Button)findViewById(R.id.button_save);

    saveButton.setOnClickListener(new View.OnClickListener(){

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            String time;
            String date;

            date = dateDisplay.getText().toString();
            time = hours + " hour(s) " + mins + " minute(s)";


            TabProDB db;
            db = new TabProDB(Recorder.this);
            db.open();

            boolean findSameDay = false;
            Cursor c = db.GetAllRecords();

              if(c!=null)
              {
                  if (c.moveToFirst())
                  {
                    do {
                        String dateToCompare = c.getString(c.getColumnIndex(TabProDB.KEY_DATE));
                        if(dateToCompare.equalsIgnoreCase(date))
                        {
                            findSameDay = true;
                        }
                    } while (c.moveToNext());
                  }
              }
            if(findSameDay!=true)
            {
                long id = db.insertRecord(date, time);
                db.close();
                Toast.makeText(Recorder.this, "Record Saved" , Toast.LENGTH_SHORT).show();
            }
            else
            {
                Toast.makeText(Recorder.this, "You have already recorded the today: " + date, Toast.LENGTH_SHORT).show();
                db.close();
            }
            switchTabInActivity(1);
        }

    });

}

public void switchTabInActivity(int index)
{
    TabBar parentActivity;
    parentActivity = (TabBar)this.getParent();
    parentActivity.switchTab(index);

}

@Override
public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
// TODO Auto-generated method stub
if(arg0.getId() == R.id.seekBar_hour){
    // update hour value
    hours = arg1;
    sbHourValue.setText(Integer.toString(arg1)+" hour(s)");

}
else{
    // update minute value
    mins = arg1;
    sbMinValue.setText(Integer.toString(arg1)+" minute(s)");
}       
}

@Override
public void onStartTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub

}

@Override
public void onStopTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub

}
}

历史课

package com.example.tabpro;

import java.util.ArrayList;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class History  extends Activity implements OnItemClickListener {


int getdbID;
String Date;
String Time;
ListView date_time_ListView;
ArrayList<String> listItems = null;
ArrayAdapter arrayAdapter = null;

public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.history);

    date_time_ListView = (ListView) findViewById(R.id.listView1);

    TabProDB db = new TabProDB(this);

        try{
            listItems = new ArrayList<String>();
            db.open();
            Cursor c = db.GetAllRecords();
            if(c!=null)
            {
                if (c.moveToFirst())
                {
                   do{
                        String date1 = c.getString(c.getColumnIndex(TabProDB.KEY_DATE) );
                        String time1 = c.getString(c.getColumnIndex(TabProDB.KEY_TIME) );
                        String date_time1 = date1 + "\n" +time1;
                        listItems.add(date_time1);
                    }while (c.moveToNext());
                  }
              }
              db.close();

         }catch (Exception e) {}

         arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, listItems );

         date_time_ListView.setAdapter(arrayAdapter);
         date_time_ListView.setOnItemClickListener(this);


         date_time_ListView.setOnItemLongClickListener(new OnItemLongClickListener(){

                @Override
                public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
                        int position, long arg3) {
                    // TODO Auto-generated method stub
                    AlertDialog.Builder ad  = new AlertDialog.Builder(History.this);
                    ad.setTitle("Delete?");
                    ad.setMessage("Are you sure you want to delete this record?");
                    final int positionToRemove = position;
                    String selectedFromList = (date_time_ListView.getItemAtPosition(position).toString());
                    String[] splitDateTime = selectedFromList.split("\n");
                    final String splitDate = splitDateTime[0];
                    Toast.makeText(History.this, splitDate, Toast.LENGTH_SHORT).show();
                    String splitTime = splitDateTime[1];
                    ad.setNegativeButton("Cancel", null);
                     ad.setPositiveButton("Ok", new AlertDialog.OnClickListener() {

                        @Override
                        public void onClick(DialogInterface arg0, int arg1) {
                            // TODO Auto-generated method stub
                            TabProDB db = new TabProDB(History.this);
                            try
                            {
                                db.open();
                                Cursor c = db.GetAllRecords();
                                if(c!=null)
                                {
                                    if(c.moveToFirst())
                                    {
                                        do
                                        {
                                            //search database to find a date that equals the date on the listview
                                            String findDate = c.getString(c.getColumnIndex(TabProDB.KEY_DATE));
                                            if(splitDate.equalsIgnoreCase(findDate))
                                            {
                                                getdbID =c.getInt(c.getColumnIndex(TabProDB.KEY_ROWID));

                                                db.deleteRow(getdbID);
                                                break;
                                            }
                                            else
                                            {

                                            }
                                        }while(c.moveToNext());

                                    }
                                }
                            }
                            catch(Exception e){}
                            db.close();

                            listItems.remove(positionToRemove);
                            arrayAdapter.notifyDataSetChanged();    

                        }

                     });
                     ad.show();
                    return false;
                }

            });
}

@Override
public void onItemClick(AdapterView<?> arg0, View view, int position, long arg3) {
    // TODO Auto-generated method stub
    Intent i = new Intent(History.this, Update.class);
    String str1[] = ((TextView) view).getText().toString().split("\n");
    String str2 = str1[0];
    String str3 = str1[1];

    i.putExtra("date", str2);
    i.putExtra("time", str3);
    i.putExtra("position", position);
    startActivity(i);

}

}
4

1 回答 1

0 
    final Intent i = new Intent().setClass(TabBar.this,
            Recorder.class);
    TabSpec spec1 = tabHost.newTabSpec("Recoder");
    spec1.setContent(i);
    spec1.setIndicator(getResources().getString(R.string.title_card_post1),
            getResources().getDrawable(R.drawable.tab1));


    final Intent i = new Intent().setClass(TabBar.this,
        History.class);
        TabSpec spec1 = tabHost.newTabSpec("History");
    spec1.setContent(i);
    spec1.setIndicator(getResources().getString(R.string.title_card_post1),
            getResources().getDrawable(R.drawable.tab1));

    tabHost.addTab(spec1);
    tabHost.addTab(spec2);

试试这个代码，让我知道这是否适合你，因为这个解决方案对我有用，而且我的一个应用程序确实有它。

于 2013-10-04T09:46:01.653 回答