Question

我正在尝试从数据库中的第二列获取值，并通过单击listview项目将其放入textview。

DBConnection类

package com.prodev;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import java.util.ArrayList;

/**
 * Created by Dev_Mohamed_Sayed on 7/21/2017.
 */

public class DBConnection extends SQLiteOpenHelper {
    public static final String DbName="azkar.db";
    public static final int Version=1;
    public DBConnection(Context context){
        super(context,DbName,null,Version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS azkar_main ( ID INTEGER, Name TEXT, Number INTEGER, PRIMARY KEY(ID) )");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS azkar_main");
        onCreate(db);
    }

    public void InsertRowAdmin(String Name,Integer Number){
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();

        contentValues.put("Name", Name);
        contentValues.put("Number", Number);
        db.insert("azkar_main", null, contentValues);
    }

    public ArrayList getAllRecord2(){
        ArrayList array_list2 = new ArrayList();
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor res = db.rawQuery("select * from azkar_main", null);
        res.moveToFirst();
        while (res.isAfterLast() == false){
            array_list2.add(res.getString(res.getColumnIndex("ID"))+ " - " + res.getString(res.getColumnIndex("Name"))+ " ..  " + res.getString(res.getColumnIndex("Number")));
            res.moveToNext();
        }
        return array_list2;
    }

    public void delete(Integer ID){
        SQLiteDatabase db = this.getWritableDatabase();
        db.execSQL("delete from azkar_main where ID="+ Integer.toString(ID));
    }
}

这是我的Acivity，我们应该在哪里工作。

package com.prodev;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.R.layout;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.TextView;

import java.util.ArrayList;

public class ListActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getSupportActionBar().setDisplayShowTitleEnabled(false);
        getSupportActionBar().setDisplayShowHomeEnabled(true);
        getSupportActionBar().setLogo(R.mipmap.ic_launcher);
        getSupportActionBar().setDisplayUseLogoEnabled(true);
        setContentView(R.layout.activity_list);
        DBConnection db = new DBConnection(this);
        ListView ls =(ListView)findViewById(R.id.ls);
        ArrayList<String> arrlist = db.getAllRecord2();
        ls.setAdapter(new ArrayAdapter<>(this, layout.simple_list_item_1, arrlist));


        ListView lv = (ListView) findViewById(R.id.ls);

        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Intent i = new Intent(ListActivity.this, MainActivity.class);
                startActivity(i);

                ListView lv = (ListView) findViewById(R.id.ls);
                TextView tv = (TextView) findViewById(R.id.textView);

                // The Missing Part
            }
        });
    }

    public void btn_save(View view){
        EditText editText =(EditText)findViewById(R.id.editText);
        ListView ls =(ListView)findViewById(R.id.ls);
        DBConnection db = new DBConnection(this);
        db.InsertRowAdmin(editText.getText().toString(), 0);

        ArrayList<String> arrlist = db.getAllRecord2();
        ls.setAdapter(new ArrayAdapter<>(this, layout.simple_list_item_1, arrlist));
        editText.setText("");
    }

    public void btn_delete(View view){
        EditText txt = (EditText)findViewById(R.id.del);
        ListView ls = (ListView)findViewById(R.id.ls);
        DBConnection db = new DBConnection(this);
        db.delete(Integer.parseInt(txt.getText().toString()));

        ArrayList<String> arrlist=db.getAllRecord2();
        ls.setAdapter(new ArrayAdapter<>(this, layout.simple_list_item_1, arrlist));
        txt.setText("");
    }

}

MainActivity

package com.prodev;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;

import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import com.google.firebase.analytics.FirebaseAnalytics;
import com.google.firebase.crash.FirebaseCrash;


public class MainActivity extends AppCompatActivity {

    private FirebaseAnalytics mFirebaseAnalytics;

    private static final String TAG = "MainActivity";

    private AdView mAdView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mFirebaseAnalytics = FirebaseAnalytics.getInstance(this);
        FirebaseCrash.log("Activity created");
        getSupportActionBar().setDisplayShowTitleEnabled(false);
        getSupportActionBar().setDisplayShowHomeEnabled(true);
        getSupportActionBar().setLogo(R.mipmap.ic_launcher);
        getSupportActionBar().setDisplayUseLogoEnabled(true);
        setContentView(R.layout.activity_main);

        mAdView = (AdView) findViewById(R.id.adView);
        AdRequest adRequest = new AdRequest.Builder().build();
        mAdView.loadAd(adRequest);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.mainmenu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            // action with ID action_refresh was selected
            case R.id.action_azkar:
                Intent i = new Intent(MainActivity.this, ListActivity.class);
                startActivity(i);
                break;
            case R.id.action_settings:

                break;
            default:
                break;
        }

        return true;
    }

}

另外我想从变量中保存数字，稍后将声明为数据库col号。我不知道如何，但后来我会担心...

Answer 1

列出项目点击事件，

@Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            Intent i = new Intent(ListActivity.this, MainActivity.class);
            i.putExtra("keyText","value to be passed!");
            startActivity(i);
        }

在你的主要活动中，

Intent i = getIntent();
String text = i.getStringExtra("keyText");
TextView tv = (TextView) findViewById(R.id.textView);
tv.setText(text);

通过listview项目单击从数据库列获取值

1 个答案: