java - 如何根据日期输入(edittext)查看数据？

Question

我想使用表布局进行 View 输出。

我的想法是这样的。
我有一个主页，称为activity_main.xml
当您单击取消按钮时，它将转到摘要页面，
称为data.xml。
在data.xml中，我有一个日期edittext，据此，当我输入日期时，例如12/2/2013，
当我单击按钮搜索后，它将向我显示它的记录。
但是，我不确定该怎么做。
如果我没有输入任何日期并单击“搜索”，它将显示所有记录。

现在，我可以显示所有记录，而无需搜索数据。
下面是我的代码。

有人可以按日期帮助我吗？
我希望我对自己的解释足够清楚。

DBAdapter.java

public class DBAdapter {



    public static final String KEY_ROWID = "_id";
    public static final String KEY_DATE = "date";
    public static final String KEY_PRICE = "fuelprice";
    public static final String KEY_FUEL = "fuelpump";
    public static final String KEY_COST = "tcost";
    public static final String KEY_ODM = "odometer";
    public static final String KEY_CON = "fcon";

    private static final String TAG = "DBAdapter";

    private static final String DATABASE_NAME = "MyDB";
    private static final String DATABASE_TABLE = "fuelLog";
    private static final int DATABASE_VERSION = 2;



    private static final String DATABASE_CREATE =
            "create table fuelLog (_id integer primary key autoincrement, " + "date text not null, fuelprice text not null, fuelpump text not null, tcost text not null, odometer text not null, fcon text not null);";


        private final Context context;    

        private DatabaseHelper DBHelper;
        private SQLiteDatabase db;

        public DBAdapter(Context ctx){
            this.context = ctx;
            DBHelper = new DatabaseHelper(context);
        }

        private static class DatabaseHelper extends SQLiteOpenHelper 
        {
            DatabaseHelper(Context context){
                super(context, DATABASE_NAME, null, DATABASE_VERSION);
            }

            public void onCreate(SQLiteDatabase db) 
            {
                try{
                    db.execSQL(DATABASE_CREATE);    
                }catch (SQLException e){
                    e.printStackTrace();
                }
            }//onCreate

            public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
            {
                Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                        + newVersion + ", which will destroy all old data");
                db.execSQL("DROP TABLE IF EXISTS contacts");
                onCreate(db);
            }//onUpgrade

        }//DatabaseHelper


        public DBAdapter open() throws SQLException 
        {
            db = DBHelper.getWritableDatabase();
            return this;
        }//open


        //---closes the database---    
        public void close() 
        {
            DBHelper.close();
        }//close


        //---insert a log into the database---
        public long insertLog(String date, String fuelprice, String fuelpump,String tcost,String odometer,String fcon ) 
        {
            ContentValues initialValues = new ContentValues();
            initialValues.put(KEY_DATE, date);
            initialValues.put(KEY_PRICE, fuelprice);
            initialValues.put(KEY_FUEL, fuelpump);
            initialValues.put(KEY_COST, tcost);
            initialValues.put(KEY_ODM, odometer);
            initialValues.put(KEY_CON, fcon);


            return db.insert(DATABASE_TABLE, null, initialValues);
        }//insertLog






    // --retrieves all the data
       public Cursor getAllLog()
        {
        return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_DATE, KEY_PRICE, KEY_FUEL,KEY_ODM,KEY_CON}, null, null, null, null, null);
        }


}

summary.java

  public class summary  extends Activity{
     TableLayout tablelayout_Log = null;
     Button searchButton = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.data);



        tablelayout_Log = (TableLayout) findViewById(R.id.tableLayout_Log);

        tablelayout_Log.setStretchAllColumns(true);   
        tablelayout_Log.setShrinkAllColumns(true);   


        //View
                searchButton = (Button) findViewById(R.id.searchBtn);
                searchButton.setOnClickListener(new OnClickListener()
                {
                    public void onClick(View v)
                    {
                        try{
                            refreshTable();
                        }
                        catch (Exception e)
                        {
                            Log.d("Fuel Log", e.getMessage());
                        }
                    }

                }); 
                }//oncreate



            public void refreshTable()
            {
                tablelayout_Log.removeAllViews();
                TableRow rowTitle = new TableRow(this);
                rowTitle.setGravity(Gravity.CENTER_HORIZONTAL);

                TextView title = new TextView(this);
                title.setText("Fuel Log");
                title.setTextSize(TypedValue.COMPLEX_UNIT_DIP,18);
                title.setGravity(Gravity.CENTER);
                title.setTypeface(Typeface.DEFAULT, Typeface.BOLD);

                TableRow.LayoutParams params = new TableRow.LayoutParams();
                params.span = 5;

                rowTitle.addView(title, params);
                tablelayout_Log.addView(rowTitle);
                DBAdapter dbAdaptor = new DBAdapter(getApplicationContext());
                Cursor cursor = null;
                try
                {
                    dbAdaptor.open();

                    cursor = dbAdaptor.getAllLog();
                    cursor.moveToFirst();
                    do{
                        long id = cursor.getLong(0);
                        String date = cursor.getString(1);
                        String price = cursor.getString(2);
                        String pump = cursor.getString(3);

                        String odometer = cursor.getString(4);
                        String fcon = cursor.getString(5);


                        TextView viewId = new TextView(getApplicationContext());
                        viewId.setText("" + id);

                        TextView viewDate = new TextView(getApplicationContext());
                        viewDate.setText(date);

                        TextView viewPrice = new TextView(getApplicationContext());
                        viewPrice.setText(price);

                        TextView viewPump = new TextView(getApplicationContext());
                        viewPump.setText(pump);


                        TextView viewOdometer = new TextView(getApplicationContext());
                        viewOdometer.setText(odometer);

                        TextView viewCon = new TextView(getApplicationContext());
                        viewCon.setText(fcon);

                        TableRow row = new TableRow(this);
                        row.setGravity(Gravity.CENTER_HORIZONTAL);
                        row.addView(viewId);
                        row.addView(viewDate);
                        row.addView(viewPrice);
                        row.addView(viewPump);
                        row.addView(viewOdometer);
                        row.addView(viewCon);
                        tablelayout_Log.addView(row);
                    }
                    while(cursor.moveToNext());
                }
                catch(Exception e){
                    Log.d("Fuel Log", e.getMessage());
                }
                finally
                {
                    if (cursor != null)
                        cursor.close();
                    if(dbAdaptor != null)
                        dbAdaptor.close();
                }
            }//refreshTable

        }//main

MainActivity.java

public class MainActivity extends Activity {
    TableLayout tablelayout_Contacts = null;
    Button insertButton = null;
    EditText nameEdit = null;
    EditText contactEdit = null;
    Button viewButton = null;
    Button deleteButton = null;

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

            tablelayout_Contacts = (TableLayout) findViewById(R.id.tableLayout_Contacts);

            tablelayout_Contacts.setStretchAllColumns(true);   
            tablelayout_Contacts.setShrinkAllColumns(true);   

            nameEdit = (EditText) findViewById(R.id.editText_Name);
            contactEdit = (EditText) findViewById(R.id.editText_Number);







    insertButton = (Button) findViewById(R.id.button1);
    insertButton.setOnClickListener(new OnClickListener()
    {
        public void onClick(View v)
        {
            DBAdapter dbAdaptor = new DBAdapter(getApplicationContext());
            try{
                dbAdaptor.open();
                String name = nameEdit.getText().toString();
                String number = contactEdit.getText().toString();
                dbAdaptor.insertContact(name, number);
            }
            catch (Exception e)
            {
                Log.d("Contact Manager",e.getMessage());
            }
            finally{
                if(dbAdaptor != null)
                    dbAdaptor.close();
            }
        }
    });



    //View records
    viewButton = (Button) findViewById(R.id.button2);
    viewButton.setOnClickListener(new OnClickListener()
    {
        public void onClick(View v)
        {
            try{
                refreshTable();
            }
            catch (Exception e)
            {
                Log.d("Contact Manager",e.getMessage());
            }
        }
    });

    //delete records
    deleteButton = (Button) findViewById(R.id.button3);
    deleteButton.setOnClickListener(new OnClickListener()
    {
        public void onClick(View v)
        {
            DBAdapter dbAdaptor = new DBAdapter(getApplicationContext());

            try{
                refreshTable();
                String name = nameEdit.getText().toString();


                if(!name.equals(""))
                {
                    dbAdaptor.deleteContact(name);
                }

            }
            catch (Exception e)
            {
                Log.d("Contact Manager",e.getMessage());
            }
        }
    });



    }//oncreate











    //refresh table


    public void refreshTable()
    {
        tablelayout_Contacts.removeAllViews();
        TableRow rowTitle = new TableRow(this);
        rowTitle.setGravity(Gravity.CENTER_HORIZONTAL);

        TextView title = new TextView(this);
        title.setText("Contacts");
        title.setTextSize(TypedValue.COMPLEX_UNIT_DIP,18);
        title.setGravity(Gravity.CENTER);
        title.setTypeface(Typeface.DEFAULT, Typeface.BOLD);

        TableRow.LayoutParams params = new TableRow.LayoutParams();

        params.span =3;
        rowTitle.addView(title,params);
        tablelayout_Contacts.addView(rowTitle);
        DBAdapter dbAdaptor = new DBAdapter(getApplicationContext());

        Cursor cursor = null;

        try{
            dbAdaptor.open();
            cursor = dbAdaptor.getAllContacts();
            cursor.moveToFirst();
            do{
                long id = cursor.getLong(0);
                String name = cursor.getString(1);
                String contact = cursor.getString(2);

                TextView idView = new TextView(getApplicationContext());
                idView.setText("" + id);

                TextView nameView = new TextView(getApplicationContext());
                nameView.setText(name);

                TextView contactView = new TextView(getApplicationContext());
                nameView.setText(contact);

                TableRow row = new TableRow(this);
                row.setGravity(Gravity.CENTER_HORIZONTAL);
                row.addView(idView);
                row.addView(nameView);
                row.addView(contactView);

                tablelayout_Contacts.addView(row);
            }
            while (cursor.moveToNext());
        }
        catch (Exception e)
        {
            Log.d("Contact Manager", e.getMessage());
        }
        finally{
            if (cursor != null)
                cursor.close();
            if(dbAdaptor != null)
                dbAdaptor.close();


            }   
    }




}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
     android:orientation="vertical"
    android:layout_height="fill_parent"
    tools:context=".MainActivity" >


   <TableLayout 
        android:id="@+id/tableLayout1" 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:stretchColumns="1">

        <TableRow 
            android:id="@+id/tableRow1" 
            android:layout_width="wrap_content" 
            android:layout_height="wrap_content">
             <TextView 
                android:id="@+id/datetxtview"
                android:text="@string/date"  
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>
              <EditText
                android:id="@+id/date" 
                android:text=""
                android:inputType="date" 
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </EditText>
       </TableRow>

         <TableRow 
            android:id="@+id/tableRow2" 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
            <TextView 
                android:id="@+id/fuelpricetxtview" 
                android:text="@string/fuelprice"
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>
            <EditText
                android:id="@+id/fuelprice" 
                android:text="" 
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </EditText>
        </TableRow>
         <TableRow 
            android:id="@+id/tableRow3" 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
            <TextView 
                android:id="@+id/fuelpumptxtview" 
                android:text="@string/fuelpump"
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>
            <EditText
                android:id="@+id/fuelpump" 
                android:text="" 
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </EditText>
        </TableRow>


          <TableRow 
            android:id="@+id/tableRow4" 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
            <TextView 
                android:id="@+id/totalcosttxtview" 
                android:text="@string/totalcost"
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>

            <TextView
                android:id="@+id/tcost"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="" />

        </TableRow>



         <TableRow 
            android:id="@+id/tableRow5" 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
            <TextView 
                android:id="@+id/odometertxtview" 
                android:text="@string/odometer"
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>

            <EditText
                android:id="@+id/odometer"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10" >

                <requestFocus />
            </EditText>

        </TableRow>   
         <TableRow 
            android:id="@+id/tableRow6" 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
            <TextView 
                android:id="@+id/fctxtview" 
                android:text="@string/fc"
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>

            <TextView
                android:id="@+id/fcon"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="" />

        </TableRow>     
        </TableLayout>


    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/saveBTN"
            android:text="@string/save"
            android:layout_width="wrap_content"
            android:layout_height="60px" >
        </Button>

          <Button
            android:id="@+id/updateBTN"
            android:text="Update"
            android:layout_width="wrap_content"
            android:layout_height="60px" >
        </Button>
        <Button
            android:id="@+id/cancelBTN"
            android:text="@string/cancel"
            android:layout_width="wrap_content"
            android:layout_height="60px" >
        </Button>
    </LinearLayout>



</LinearLayout>

data.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >


 <TableLayout 
        android:id="@+id/tableLayout1" 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:stretchColumns="1">

        <TableRow 
            android:id="@+id/tableRow1" 
            android:layout_width="wrap_content" 
            android:layout_height="wrap_content">
             <TextView 
                android:id="@+id/datetxtview"
                android:text="@string/date"  
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>

            <EditText
                android:id="@+id/datepast" 
                android:text=""
                android:inputType="date" 
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </EditText>
        </TableRow>

         <TableRow 
            android:id="@+id/tableRow2" 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
            <TextView 
                android:id="@+id/fctxtview" 
                android:text="@string/fc"
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>
            <EditText
                android:id="@+id/fc" 
                android:text="" 
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </EditText>
        </TableRow>
         <TableRow 
            android:id="@+id/tableRow3" 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
            <TextView 
                android:id="@+id/highpricetxtview" 
                android:text="@string/highprice"
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </TextView>
            <EditText
                android:id="@+id/highprice" 
                android:text="" 
                android:layout_width="wrap_content" 
                android:layout_height="wrap_content">
            </EditText>
        </TableRow>
         <TableRow 
            android:id="@+id/tableRow4" 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
         <Button
     android:id="@+id/searchBtn"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:text="Search" />
     <Button
     android:id="@+id/deleteBTN"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:text="Delete" />
        <Button
     android:id="@+id/backBTN"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:text="Back" />
        </TableRow>
       </TableLayout>

 <TableLayout    
         android:id="@+id/tableLayout_Log" 
         android:layout_width="fill_parent" 
         android:layout_height="wrap_content" >
    </TableLayout>



</LinearLayout>

Answer 1

您得到的错误是一个空指针，这意味着MainActivity中第205行或该行使用的某些对象为空。首先检查该内容，然后尝试再次运行。