Question

我有将问题转换为片段的问题，但“getBaseContext”和“this”的功能无法正常工作

package prj.apdev.c17;


import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;

public class DataBase extends Fragment {
    
    TempatDatabase dm;
    EditText inama, idosis, ilabel;
    Button btambah;
    TableLayout tabel4data;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View va = inflater.inflate(R.layout.mapping_fragment, container, false);
        return va;
    

        dm = new TempatDatabase(this);
        tabel4data = (TableLayout) va.findViewById (R.id.tabel_data);
        inama = (EditText) va.findViewById(R.id.dose_nama_e);
        idosis = (EditText) va.findViewById(R.id.dose_dosis_e);
        ilabel = (EditText) va.findViewById(R.id.dose_label_e);
        btambah = (Button) va.findViewById(R.id.button_add);
        
        btambah.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                simpanData();
            }
        });
        updateTable();
    }

    private void updateTable() {
        // TODO Auto-generated method stub
        // TODO Auto-generated method stub
        while (tabel4data.getChildCount() > 1) {
            tabel4data.removeViewAt(1);
        }
        double aa = tabel4data.getChildCount();
        String a = String.valueOf(aa);
        Toast.makeText(getBaseContext(), "tabel data child : " + a,
                Toast.LENGTH_SHORT).show();

        ArrayList<ArrayList<Object>> data = dm.ambilSemuaBaris();//

        for (int posisi = 0; posisi < data.size(); posisi++) {
            TableRow tabelBaris = new TableRow(this);
            ArrayList<Object> baris = data.get(posisi);

            TextView idTxt = new TextView(this);
            idTxt.setText(baris.get(0).toString());
            tabelBaris.addView(idTxt);

            TextView namaTxt = new TextView(this);
            namaTxt.setText(baris.get(1).toString());
            tabelBaris.addView(namaTxt);

            TextView dosisTxt = new TextView(this);
            dosisTxt.setText(baris.get(2).toString());
            tabelBaris.addView(dosisTxt);

            TextView labelTxt = new TextView(this);
            labelTxt.setText(baris.get(3).toString());
            tabelBaris.addView(labelTxt);

            tabel4data.addView(tabelBaris);

        }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
    private void simpanData() {
        // TODO Auto-generated method stub
        try {
            dm.addRow(inama.getText().toString(), idosis.getText().toString(), ilabel.getText().toString());
            Toast.makeText(getBaseContext(), inama.getText().toString() + ", berhasil disimpan",
                    Toast.LENGTH_SHORT).show();
            updateTable();
            
            kosongkanField();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            Toast.makeText(getBaseContext(), "gagal simpan, " + e.toString(),
                    Toast.LENGTH_LONG).show();
        }
    }
    
    private void kosongkanField() {
        // TODO Auto-generated method stub
        inama.setText("");
        idosis.setText("");
        ilabel.setText("");
    }
}

这是我的数据库类

package prj.apdev.c17;

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 java.util.ArrayList;

public class TempatDatabase {

    private static final String ROW_ID = "_id";
    private static final String ROW_NAMA = "nama";
    private static final String ROW_DOSIS = "dosis";
    private static final String ROW_LABEL = "label";

    private static final String NAMA_DB ="APdev";
    private static final String NAMA_TABEL="Doseme";
    private static final int DB_VERSION=1;

    private static final String CREATE_TABLE =
            "create table "+NAMA_TABEL+" ("+ROW_ID+" integer PRIMARY KEY autoincrement, "+ROW_NAMA+" text,"+ROW_DOSIS+" text, "+ROW_LABEL+" text)";
    //membuat mendeklarasikan itu adalah context
    private final Context context;
    //membuat mendeklarasikan DatabaseOpenHelper itu adalah dbhelper
    private DatabaseOpenHelper dbhelper;
    //membuat mendeklarasikan SQLiteDatabase itu adalah db
    private SQLiteDatabase db;

    //mengambil context untuk mengakses system di android
    public TempatDatabase(DataBase ctx) {
        //mendeklarasikan ctx adalah context ( context context di ganti ctx )
        this.context = ctx;
        // membuat DatabaseOpenHelper
        dbhelper = new DatabaseOpenHelper(context);
        //menuliskan DatabaseOpenHelper = SQLiteDatabase
        db = dbhelper.getWritableDatabase();
    }



    private static class DatabaseOpenHelper extends SQLiteOpenHelper {
        //membuat database
        public DatabaseOpenHelper(Context context) {
            super(context, NAMA_DB, null, DB_VERSION);
            // TODO Auto-generated constructor stub
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            // TODO Auto-generated method stub
            db.execSQL(CREATE_TABLE);
        }
        //memperbarui database bila sudah ada
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVer, int newVer) {
            // TODO Auto-generated method stub
            db.execSQL("DROP TABLE IF EXISTS "+NAMA_DB);
            onCreate(db);

        }
    }
    //menutup DatabaseOpenHelper
    public void close() {
        dbhelper.close();
    }
    //menambahkan pada row
    public void addRow(String nama, String dosis, String label) {

        ContentValues values = new ContentValues();
        values.put(ROW_NAMA, nama);
        values.put(ROW_DOSIS, dosis);
        values.put(ROW_LABEL, label);

        try {
            //menambahkan nama tabel bila tidak akan error
            // db.delete(NAMA_TABEL, null, null);
            db.insert(NAMA_TABEL, null, values);
        } catch (Exception e) {
            Log.e("DB ERROR", e.toString());
            e.printStackTrace();
        }
    }
    //membuat array pada table layout
    public ArrayList<ArrayList<Object>> ambilSemuaBaris() {
        ArrayList<ArrayList<Object>> dataArray = new ArrayList<ArrayList<Object>>();
        Cursor cur;
        try {
            cur = db.query(NAMA_TABEL,
                    new String[] { ROW_ID, ROW_NAMA, ROW_DOSIS, ROW_LABEL }, null, null,
                    null, null, null);
            cur.moveToFirst();
            if (!cur.isAfterLast()) {
                do {
                    ArrayList<Object> dataList = new ArrayList<Object>();
                    dataList.add(cur.getLong(0));
                    dataList.add(cur.getString(1));
                    dataList.add(cur.getString(2));
                    dataList.add(cur.getString(3));

                    dataArray.add(dataList);
                } while (cur.moveToNext());
            }

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            Log.e("DEBE ERROR", e.toString());
        }
        return dataArray;
    }
}

或者如果您有任何方法可以完成此条件，您可以将其包括在内。感谢

Answer 1

您可以使用getActivity（）。getBaseContext，它返回与片段关联的活动。

Answer 2

您的 TempatDatabase 构造函数中的上下文类型为 DataBase 。用上下文即

进行更改

public TempatDatabase(Context ctx) {
        //mendeklarasikan ctx adalah context ( context context di ganti ctx )
        this.context = ctx;
        // membuat DatabaseOpenHelper
        dbhelper = new DatabaseOpenHelper(context);
        //menuliskan DatabaseOpenHelper = SQLiteDatabase
        db = dbhelper.getWritableDatabase();
    }

并且片段 getActivity（）方法将返回上下文

Answer 3

问题已解决

我已经意识到这个功能＆＃34;返回＆＃34;必须在部分的末尾

＆＃13;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View va = inflater.inflate(R.layout.dose_fragment, container, false);
        
        dm = new TempatDatabase(getActivity());
        tabel4data = (TableLayout) va.findViewById(R.id.tabel_data);
        inama = (EditText) va.findViewById(R.id.dose_nama_e);
        idosis = (EditText) va.findViewById(R.id.dose_dosis_e);
        ilabel = (EditText) va.findViewById(R.id.dose_label_e);
        btambah = (Button) va.findViewById(R.id.button_add);

        btambah.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                simpanData();
            }
        });
        updateTable();
        return va;
    }

＆＃13;

感谢帮助人们。

将活动转换为可以调用活动的片段

3 个答案: