如何通过单击“搜索”按钮从android数据库中检索记录？

Question

I have started coding for Finder app which contains employee records and user will able to find employee record by using 'id' when click on Search button in useractivity.java and data should display in Empdetails.java activity in textview contains 3 textfields to display. Below is my code , Please help me in this

My requirement : I want to retrieve a single record by giving an id in UserActivity.java and when i click on Search button it should get a record details in Empdetails.java in text view

Output:

id: 12345

name : vijay kumar

Email: vijay@gmail.com

like above shown

Thanks inadvance Vijay Kumar.

1) AdminActivity.java

public class AdminActivity extends Activity {

String id,name,email;
SQLiteDatabase db;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_admin);
    db=openOrCreateDatabase("EMP",MODE_PRIVATE,null);
    db.execSQL("CREATE TABLE IF NOT EXISTS EMP(id varchar,name varchar,email varchar);");
}

public void Submit(View view)
{       
EditText edittext1=(EditText) findViewById(R.id.id);
    EditText edittext2=(EditText) findViewById(R.id.name);
    EditText edittext3=(EditText) findViewById(R.id.email);
    id=edittext1.getText().toString();
    name=edittext2.getText().toString();
    email=edittext3.getText().toString();
    db.execSQL("INSERT INTO EMP(id,name,email) values ('"+id+"','"+name+"','"+email+"');");

    if(id.equals("") && name.equals("") && email.equals(""))
    {
        Toast.makeText(getApplicationContext(), "Please enter details and submit", Toast.LENGTH_SHORT).show();
    }
    else 
        if(id.equals(""))
       {
            Toast toast=new Toast (getApplicationContext());
            toast.setDuration(Toast.LENGTH_LONG);
            Toast.makeText(getApplicationContext(), "Enter id....", Toast.LENGTH_SHORT).show();
       }
    else
        if(name.equals(""))
           {
            Toast toast=new Toast (getApplicationContext());
            toast.setDuration(Toast.LENGTH_LONG);
            Toast.makeText(getApplicationContext(), "Enter Name....", Toast.LENGTH_SHORT).show();
           }
        else
             if(email.equals(""))
            {
            Toast toast=new Toast (getApplicationContext());
            toast.setDuration(Toast.LENGTH_LONG);
             Toast.makeText(getApplicationContext(), "Enter email.....", Toast.LENGTH_SHORT).show();
            }
             else 
                { 
                    Toast toast=new Toast (getApplicationContext());
                    toast.setDuration(Toast.LENGTH_LONG);
                    edittext1.setText("");
                    edittext2.setText("");
                    edittext3.setText("");
                    Toast.makeText(getApplicationContext(), "Data submitted successfully", Toast.LENGTH_SHORT).show();
                    db.close();
                 }
            }

public void Exit(View view){
    System.exit(0);
}

}

2) UserAvtivity.java

public class UserActivity extends Activity {


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

    public void Search(View view)
    {
    /////???????????????
    }

    public void Exit(View view)
    {
    System.exit(0);
    }
}

Answer 1

Place an editText on UserActivity class for id search. and on onClickListener of a Button using sql query retrieve data from database (SELECT * From tableName where id = (Here put id no where user is going to search for))and display it in a listview. For simple example use this reference. http://javapapers.com/android/android-sqlite-database/

Answer 2

I will explain the logical method to do this:

You will need to check the ID you get from the user, and compare this ID with each ID stored in the database. Once you find a match, you should collect all the details under that ID. So for this you will require a readable database, and then try to collect the information using a Cursor .

Check this for further info: http://www.vogella.com/tutorials/AndroidSQLite/article.html

Write all this code within the onClick() method of your search button.

EDIT: Code to include the above functionality in onClick() event:

search.setOnClickListener(new View.OnClickListener() {

        @SuppressWarnings("deprecation")
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            //Include your code here
        }   
     });

Also create a search button in your layout and instantiate it using

 private Button search = null; // This line inside your MainActivity class
 search = (Button)findViewById(R.id.search); //This line inside onCreate function.

As for the code to actually implement that logic, check the link i gave you and try coding it on you own.

Answer 3

Create a new Class for creating the Database and doing queries/selects, inserts and updates.

It will bi nice to separate your SQL script - use String variables

private static final String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS EMP(id varchar, name varchar, email varchar);";

to insert data use db.insert , select db.select or rawQuery . You need to use Cursor to retrieve the data from the DB query. After getting the data from the Cursor you can arrange it as you wish.

private static final String SELECT_ID = "SELECT name, mail FROM EMP WHERE id = ? ;";

Your DB id must be INTEGER and not a varchar - it is a Primary Key or ? Primary Key: http://en.wikipedia.org/wiki/Unique_key SQLite Tuts: http://www.tutorialspoint.com/sqlite/index.htm

http://developer.android.com/training/basics/data-storage/databases.html

Code for the Search

Button search = (Button) findViewById(R.id.but_search);
search.setOnClickListener(new View.OnClickListener() {
         public void onClick(View v) {
             // DO queries, Update TextView or call your methods
         }
     });

This is bad:

id=edittext1.getText().toString();
name=edittext2.getText().toString();
email=edittext3.getText().toString();
db.execSQL("INSERT INTO EMP(id,name,email) values ('"+id+"','"+name+"','"+email+"');");

It will be nice first to check the data and then to insert it into the Database.

 if(email.lenght() > 0 ){
 // check other data, do things
 }