android - 如何在单击按钮时在数据库中添加数据？

Question

我是 Android 的新手，下面是我的代码我想通过点击按钮在数据库中添加数据但是当我点击按钮时我的应用程序崩溃了谁能建议我任何解决方案这是我的代码:

public class Third extends Activity implements OnClickListener{
Button btn;
SQLiteDatabase db;
EditText edit1;
EditText edit2;
EditText edit3;

@Override
protected void onCreate(Bundle icicle) {
// TODO Auto-generated method stub
super.onCreate(icicle);
setContentView(R.layout.mit);
SQLiteDatabase db;
db = openOrCreateDatabase("doctorinfo.db", SQLiteDatabase.CREATE_IF_NECESSARY, null);
db.setVersion(1);
db.setLocale(Locale.getDefault());
db.setLockingEnabled(true);
final String CREATE_TABLE_COUNTRIES ="CREATE TABLE med_d ("+ "id INTEGER PRIMARY KEY AUTOINCREMENT,"+ "DOC_NAME TEXT,"+ "DOC_NO TEXT,"+ "DOC_EMAIL TEXT);";
//db.execSQL(CREATE_TABLE_COUNTRIES);
btn=(Button)findViewById(R.id.button1);
edit1=(EditText)findViewById(R.id.editText1);
edit2=(EditText)findViewById(R.id.editText2);
edit3=(EditText)findViewById(R.id.editText3);

btn.setOnClickListener(this);


}

@Override
public void onClick(View arg0) {
String d=edit1.getText().toString();
String m=edit2.getText().toString();
String p=edit3.getText().toString();

ContentValues values = new ContentValues();
values.put("DOC_NAME",d );
values.put("DOC_NO",m);
values.put("DOC_EMAIL",p);
//long countryId = db.insert("med_d", null, values);
//try {
db.insertOrThrow("med_d", null,values);
}// catch (Exception e) {
//Log.e("Add Error", e.toString());
//e.printStackTrace();
//}



}

Answer 1

SQLITEOPENHELPER 类

package com.db.demo;


import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.provider.BaseColumns;

/**
 * Subclass of the {@link SQLiteOpenHelper} that sets up the database for the
 * demo.
 * 
 * @author Kah
 */
public class DatabaseHelper extends SQLiteOpenHelper {

public DatabaseHelper(Context context) {
    super(context, "CursorDemo", null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE IF NOT EXISTS names ("
            + BaseColumns._ID
            + " INTEGER PRIMARY KEY AUTOINCREMENT, first VARCHAR, last VARCHAR)");
    db.execSQL("INSERT INTO names (first, last) VALUES ('John', 'Doe')");
    db.execSQL("INSERT INTO names (first, last) VALUES ('James', 'Kirk')");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // Steps to upgrade the database for the new version ...
}

**** Activity 课****

package com.db.demo;


import android.app.ListActivity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.provider.BaseColumns;
import android.widget.CursorAdapter;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

public class DataHandlingActivity extends ListActivity{
    private SQLiteDatabase database;
 String fields[] = { "first", "last", BaseColumns._ID };
    private CursorAdapter dataSource;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    DatabaseHelper helper = new DatabaseHelper(this);
    database = helper.getReadableDatabase();
    Cursor data = database.query("names", fields, null, null, null, null,
            null);

    dataSource = new SimpleCursorAdapter(this, R.layout.row, data, fields,
            new int[] { R.id.first, R.id.last });

    ListView view = getListView();
    view.setHeaderDividersEnabled(true);
    view.addHeaderView(getLayoutInflater().inflate(R.layout.row, null));

    setListAdapter(dataSource);
}

在按钮点击中使用类似这样的东西并更改 Activity 类 update sql database with ContentValues and the update-method