将数据从SQLite数据库中拉出并在Textview中显示

Question

晚上好，stackoverflow的好人。 我希望将所有数据从数据库中提取出来并显示在TextView中。 我该如何实现？

此外，我想将数据（所有数据）从数据库中拉出，并通过soap消息将其发送到很远的WS。 我对WSDL设置没有任何疑问，但是我确实需要有关如何从数据库中提取数据并一次又一次地使用它的信息。

这是代码：

package com.example.prototype2;



import android.os.Bundle;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.support.v4.app.NavUtils;

public class AddGlucose extends Activity implements OnClickListener {

final String LOG_TAG = "myLogs";

Button btnAdd, btnRead, btnClear;
  EditText etGlucose, etTime, etDate;

  DBHelper dbHelper;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_add_glucose);
 // Show the Up button in the action bar.
 setupActionBar();

 btnAdd = (Button) findViewById(R.id.btnAdd);
 btnAdd.setOnClickListener(this);

 btnRead = (Button) findViewById(R.id.btnRead);
 btnRead.setOnClickListener(this);

 btnClear = (Button) findViewById(R.id.btnClear);
 btnClear.setOnClickListener(this);

 etGlucose = (EditText) findViewById(R.id.etGlucose);
 etTime = (EditText) findViewById(R.id.etTime);
 etDate = (EditText) findViewById(R.id.etDate);
 dbHelper = new DBHelper(this);
}

/**
* Set up the {@link android.app.ActionBar}.
*/
private void setupActionBar() {

getActionBar().setDisplayHomeAsUpEnabled(true);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.add_glucose, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
    // This ID represents the Home or Up button. In the case of this
    // activity, the Up button is shown. Use NavUtils to allow users
    // to navigate up one level in the application structure. For
    // more details, see the Navigation pattern on Android Design:
    //
    // http://developer.android.com/design/patterns/navigation.html#up-vs-back
    //
    NavUtils.navigateUpFromSameTask(this);
    return true;
}
return super.onOptionsItemSelected(item);
}

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
ContentValues cv = new ContentValues();
String glucose = etGlucose.getText().toString();
String time = etTime.getText().toString();
String date = etDate.getText().toString();

SQLiteDatabase db = dbHelper.getWritableDatabase();

switch (v.getId()) {
case R.id.btnAdd:
  Log.d(LOG_TAG, "--- Insert in mytable: ---");

  cv.put("glucose", glucose);
  cv.put("time", time);
  cv.put("date", date);
long rowID = db.insert("mytable", null, cv);
  Log.d(LOG_TAG, "row inserted, ID = " + rowID);
  break;

case R.id.btnRead:
    Log.d(LOG_TAG, "--- Rows in mytable: ---");
    Cursor c = db.query("mytable", null, null, null, null, null, null, null);
    if (c.moveToFirst()) {
        int idColIndex = c.getColumnIndex("id");
        int glucoseColIndex = c.getColumnIndex("glucose");
        int timeColIndex = c.getColumnIndex("time");
        int dateColIndex = c.getColumnIndex("date");

        do {    

            Log.d(LOG_TAG,
                    "ID = " + c.getInt(idColIndex) + 
                    ", glucose = " + c.getString(glucoseColIndex) +
                    ", time = " + c.getString(timeColIndex) + ", date = " +       c.getString(dateColIndex));
        } while (c.moveToNext());
    } else
        Log.d(LOG_TAG, "0 rows");
    c.close();
    break;

 case R.id.btnClear:
  Log.d(LOG_TAG, "--- Clear mytable: ---");

  int clearCount = db.delete("mytable", null, null);
  Log.d(LOG_TAG, "deleted rows count = " + clearCount);
  break;
}
dbHelper.close();
}

class DBHelper extends SQLiteOpenHelper {

    public DBHelper(Context context) {

      super(context, "mytable", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
      Log.d(LOG_TAG, "--- onCreate database ---");
      // создаем таблицу с полями
      db.execSQL("create table mytable ("
          + "id integer primary key autoincrement," 
          + "glucose text,"
          + "time text," + "date text" + ");");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
  }

 }

Answer 1

这是一个非常好的SQLite示例代码的链接： http : //www.androidhive.info/2011/11/android-sqlite-database-tutorial/

因此，您只需要为数据库自定义代码，但我想提醒您，如果为行元素创建自定义对象（例如示例代码），则将更加轻松自如。

Answer 2

您刚刚在一个类中插入了太多代码，似乎没有红线。 按照本教程和以下教程进行操作，只需根据需要更改解释的代码即可。 一切工作正常，设置后将教您如何从数据库中获取信息。

数据库是如此重要，以至于您应该占用一点时间。

图1