如何從兩列的SQLite的Android得值，而在另一個活動

Question

package com.OneTouch.locationprovider; 

import android.app.Activity; 
import android.app.AlertDialog.Builder; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.EditText; 

public class Contact extends Activity implements OnClickListener 
{ 
    EditText editName,editLat,editLng,editnumber; 
    Button btnAdd,btnDelete,btnModify,btnView,btnViewAll,btnShowInfo; 
    SQLiteDatabase db; 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_contact); 
    editName=(EditText)findViewById(R.id.editName); 
     editLat=(EditText)findViewById(R.id.editLat); 
     editLng=(EditText)findViewById(R.id.editLng); 
     editnumber=(EditText)findViewById(R.id.editnumber); 
     btnAdd=(Button)findViewById(R.id.btnAdd); 
     btnDelete=(Button)findViewById(R.id.btnDelete); 
    // btnModify=(Button)findViewById(R.id.btnModify); 
    btnView=(Button)findViewById(R.id.btnView); 
     btnViewAll=(Button)findViewById(R.id.btnViewAll); 
    // btnShowInfo=(Button)findViewById(R.id.btnShowInfo); 
    btnAdd.setOnClickListener(this); 
    btnDelete.setOnClickListener(this); 
    // btnModify.setOnClickListener(this); 
     btnView.setOnClickListener(this); 
     btnViewAll.setOnClickListener(this); 
    // btnShowInfo.setOnClickListener(this); 
     db=openOrCreateDatabase("ContactsDB", Context.MODE_PRIVATE, null); 
     db.execSQL("CREATE TABLE IF NOT EXISTS contacts(name VARCHAR,lat VARCHAR,lng VARCHAR,eid VARCHAR);"); 
    } 
    public void onClick(View view) 
    { 
     if(view==btnAdd) 
     { 
      if(editName.getText().toString().trim().length()==0|| 
      editLat.getText().toString().trim().length()==0|| 
        editLng.getText().toString().trim().length()==0|| 
      editnumber.getText().toString().trim().length()==0) 
      { 
       showMessage("Error", "Please enter all values"); 
       return; 
      } 
      db.execSQL("INSERT INTO contacts VALUES('"+editName.getText()+"','"+editLat.getText()+"','"+editLng.getText()+ 
        "','"+editnumber.getText()+"');"); 
      showMessage("Success", "Record added"); 
      clearText(); 
     } 
     if(view==btnDelete) 
     { 
      if(editName.getText().toString().trim().length()==0) 
      { 
       showMessage("Error", "Please enter Name"); 
       return; 
      } 
      Cursor c=db.rawQuery("SELECT * FROM contacts WHERE name='"+editName.getText()+"'", null); 
      if(c.moveToFirst()) 
      { 
       db.execSQL("DELETE FROM contacts WHERE name='"+editName.getText()+"'"); 
       showMessage("Success", "Record Deleted"); 
      } 
      else 
      { 
      showMessage("Error", "Invalid Name"); 
      } 
      clearText(); 
     } 
     if(view==btnModify) 
    { 
      if(editName.getText().toString().trim().length()==0) 
      { 
       showMessage("Error", "Please enter Name"); 
       return; 
      } 
      Cursor c=db.rawQuery("SELECT * FROM contacts WHERE name='"+editName.getText()+"'", null); 
     if(c.moveToFirst()) 
      { 
       db.execSQL("UPDATE contacts SET lat='"+editLat.getText()+"',lng='"+editLng.getText()+"',marks='"+editnumber.getText()+ 
         "' WHERE name='"+editName.getText()+"'"); 
       showMessage("Success", "Record Modified"); 
      } 
      else 
     { 
       showMessage("Error", "Invalid Name"); 
     } 
     clearText(); 
     } 
     if(view==btnView) 
     { 
      if(editName.getText().toString().trim().length()==0) 
      { 
       showMessage("Error", "Please enter Name"); 
       return; 
      } 
      Cursor c=db.rawQuery("SELECT * FROM contacts WHERE name='"+editName.getText()+"'", null); 
      if(c.moveToFirst()) 
      { 
       editLat.setText(c.getString(1)); 
       editLng.setText(c.getString(2)); 
       editnumber.setText(c.getString(3)); 
      } 
      else 
      { 
       showMessage("Error", "Invalid Name"); 
       clearText(); 
      } 
     } 
     if(view==btnViewAll) 
     { 
      Cursor c=db.rawQuery("SELECT * FROM contacts", null); 
      if(c.getCount()==0) 
      { 
       showMessage("Error", "No records found"); 
       return; 
      } 
      StringBuffer buffer=new StringBuffer(); 
     while(c.moveToNext()) 
      { 
       buffer.append("Name: "+c.getString(0)+"\n"); 
       buffer.append("Lat: "+c.getString(1)+"\n"); 
       buffer.append("Lng: "+c.getString(2)+"\n"); 
       buffer.append("Number: "+c.getString(3)+"\n\n"); 
      } 
      showMessage("Contact Details", buffer.toString()); 
     } 
     if(view==btnShowInfo) 
     { 
      showMessage("Contacts DataBase", "Developed for OneTouch"); 
     } 
    } 
    public void showMessage(String title,String message) 
    { 
     Builder builder=new Builder(this); 
     builder.setCancelable(true); 
     builder.setTitle(title); 
     builder.setMessage(message); 
     builder.show(); 
    } 
    public void clearText() 
    { 
     editName.setText(""); 
     editLat.setText(""); 
     editLng.setText(""); 
     editnumber.setText(""); 
     editName.requestFocus(); 
    } 

}

這是我從中得到存儲在該緯度和經度值我的數據庫的代碼中使用它數據庫並在我的主要活動中使用它。我無法編寫任何可以實現它的方法。請幫助我完成所需方法的編碼。我是新到Android .....

Answer 1

您可以將數據發送到使用其他活動，例如，意圖額外： 你可以看到這篇文章： How to use putExtra() and getExtra() for string data

的另一種方式是設定數據作爲你的應用程序類的變量（有很多方法可以做到這一點）： 其中一個，你可以在這裏閱讀Using the Android Application class to persist data