Question

我目前正在尝试使用列表填充列表视图，我的代码看起来像这样

    ListView lv = (ListView) findViewById(R.id.listView1);
    SQLdb sql = new SQLdb(this);
    List<AppUsage> lv_arr = sql.getAllAppUsage();

    ArrayAdapter<AppUsage> adapter = new ArrayAdapter<AppUsage>(this,
            android.R.layout.simple_list_item_1, lv_arr);

    lv.setAdapter(adapter);

AppUsage.java

public class AppUsage {

   //private variables
   String _package;
   String _timeopened;
   String _timeclosed;
   String _duration;
   String _name;

   // Empty constructor
   public AppUsage(){

   }
   // constructor
   public AppUsage(String _package, String _timeopened, String _timeclosed, String _duration, String _name){
       this._package = _package;
       this._timeopened = _timeopened;
       this._timeclosed = _timeclosed;
       this._duration = _duration;
       this._name = _name;
   }

  // package
  public void setPackage(String appPackage){
      this._package = appPackage;
  }

 // package
 public void setTimeOpened(String timeOpened){
     this._timeopened = timeOpened;
 }

// package
public void setTimeClosed(String timeClosed){
    this._timeclosed = timeClosed;
}

// package
public void setDuration(String duration){
   this._duration = duration;
}

   // setting name
   public void setName(String name){
       this._name = name;
   }



}

SQLdb.java

import java.util.ArrayList;
import java.util.List;

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

public class SQLdb extends SQLiteOpenHelper {

    public static final String DB_KEY = "key";
    public static final String DB_PACKAGE = "packageName";
    public static final String DB_TIMEOPEN = "timeOpened";
    public static final String DB_TIMECLOSED = "timeClosed";
    public static final String DB_DURATION = "duration";
    public static final String DB_NAME = "appName";


    private static final int DATABASE_VERSION = 2;
    private static final String DATABASE_NAME = "AppMonitorDB";
    private static final String DICTIONARY_TABLE_NAME = "AppData";
    private static final String DICTIONARY_TABLE_CREATE =
                "CREATE TABLE " + DICTIONARY_TABLE_NAME + " (" +
                DB_KEY + " INT PRIMARY KEY, " +
                DB_TIMEOPEN + " TEXT, " +
                DB_TIMECLOSED + " TEXT, " +
                DB_DURATION + " TEXT, " +
                DB_NAME + " TEXT, " +
                DB_PACKAGE + " TEXT);";

    SQLdb(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(DICTIONARY_TABLE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Drop older table if existed
        db.execSQL("DROP TABLE IF EXISTS " + DICTIONARY_TABLE_NAME);

        // Create tables again
        onCreate(db);
    }

       public void addAppUsage(String packageName, String timeOpened, String timeClosed, float duration, String appName) {
            SQLiteDatabase db = this.getWritableDatabase();

            ContentValues values = new ContentValues();
            values.put(DB_PACKAGE, packageName);
            values.put(DB_TIMEOPEN, timeOpened);
            values.put(DB_TIMECLOSED, timeClosed);
            values.put(DB_DURATION, duration);
            values.put(DB_NAME, appName);

            // Inserting Row
            db.insert(DICTIONARY_TABLE_NAME, null, values);
            db.close(); // Closing database connection
        }
       public AppUsage getAppUsage(int id) {
            SQLiteDatabase db = this.getReadableDatabase();

            Cursor cursor = db.query(DICTIONARY_TABLE_NAME, new String[] { DB_PACKAGE,
                    DB_TIMEOPEN, DB_TIMECLOSED, DB_DURATION, DB_NAME }, DB_PACKAGE + "=?",
                    new String[] { String.valueOf(id) }, null, null, null, null);
            if (cursor != null)
                cursor.moveToFirst();

            AppUsage usage = new AppUsage(cursor.getString(0), cursor.getString(1), cursor.getString(2), cursor.getString(3), cursor.getString(4));
            // return contact
            return usage;
        }
       public List<AppUsage> getAllAppUsage() {
            List<AppUsage> contactList = new ArrayList<AppUsage>();
            // Select All Query
            String selectQuery = "SELECT " + DB_NAME + ", " + DB_PACKAGE + ", Sum(" + DB_DURATION + ") " + DB_DURATION + " FROM "+ DICTIONARY_TABLE_NAME +" GROUP BY " + DB_NAME + ", " + DB_PACKAGE;

            SQLiteDatabase db = this.getWritableDatabase();
            Cursor cursor = db.rawQuery(selectQuery, null);

            // looping through all rows and adding to list
            if (cursor.moveToFirst()) {
                do {
                    AppUsage contact = new AppUsage();
                    contact.setName(cursor.getString(0));
                    contact.setPackage(cursor.getString(1));
                    contact.setDuration(cursor.getString(2));
                    // Adding contact to list
                    contactList.add(contact);
                } while (cursor.moveToNext());
            }

            // return contact list
            return contactList;
        }
}

我的问题是它确实已填充，但数据看起来不正确，而是使用应用程序包名称和奇怪的数字，例如下面的

com.package.name.appname@41509668

我做错了吗？

Answer 1

您需要覆盖AppUsage

的toString（）方法

如下：

@Override
public String toString()
{
  return _name;
}

当你使用默认适配器toString方法为每个对象和对象引用返回时，所以如果你想生成Class对象的列表，你需要覆盖toString()方法或者你可以创建自定义适配器

Listview没有填充正确的数据

1 个答案: