將數據從數據庫加載到數據點[]

Question

我試圖導入數據到LineGraphSeries，但我遇到問題。 我想創建一個插入到SQLite數據庫的數據的圖形（不是實時修改），我寫了下面的代碼來做到這一點。 由於我在我自己的最後一年項目中學習java，所以我對android很少有經驗，如果有人能幫忙，我會很樂於助人。

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_mediasdiab); 


    mediaglicemia = (TextView) findViewById(R.id.textmediaglicemia); 
    mediainsulina = (TextView) findViewById(R.id.textmediainsulina); 
    mediaporcoes = (TextView) findViewById(R.id.textmediaporcoes); 
    maxg = (TextView) findViewById(R.id.txtglicmax); 
    maxi = (TextView) findViewById(R.id.txtinsmax); 
    maxp = (TextView) findViewById(R.id.txtpormax); 
    ming = (TextView) findViewById(R.id.txtglicmin); 
    mini = (TextView) findViewById(R.id.txtinsmin); 
    minp = (TextView) findViewById(R.id.txtpormin); 

    try { 
     database = new Database(this); 
     conn = database.getWritableDatabase(); 
     operacoes = new operacoes(conn); 

    }catch (SQLException ex) 
    { 
     Toast.makeText(getApplicationContext(), "Base de dados não acessivel. Erro:" + ex.getMessage(), Toast.LENGTH_LONG).show(); 
    } 
    graph = (GraphView) findViewById(R.id.graficodiab); 
    listardados(); 
    gerardatapoints(); 
    LineGraphSeries<DataPoint> series = new LineGraphSeries<DataPoint>(values); 
    graph.addSeries(series); 

} 

    //The error happens here 
private void gerardatapoints(){ 
    Cursor cursor = operacoes.todoaasfilas(); 
    values = new DataPoint[idalto]; 
    for (z=0; i<idalto; z++) { 
     cursor.moveToPosition(z); 
     diablinhagli = cursor.getString(cursor.getColumnIndex("GLICEMIA")); 
     graphgic = cursor.getInt(0); 
     values[z]= new DataPoint(z, graphgic); 
    } 
    seriesglicemia = new LineGraphSeries<DataPoint>(values); 
} 

Answer 1

1.設置DataPoint數組的大小。
2.創建一個具有整型參數的數據點。
3.將數據點添加到DataPoint數組。
4.初始化LineGraphSeries與數組。

private void gerardatapoints() { 
    Cursor cursor = operacoes.todoaasfilas(); 
    values = new DataPoint[idalto]; 
    for (z=0; i<idalto; z++) { 
    cursor.moveToPosition(z); 
    diablinhagli = cursor.getString(cursor.getColumnIndex("GLICEMIA")); 
    graphgic = cursor.getInt(0); 
     //Assuming graphgic is of integer type 
     DataPoint v = new DataPoint(z, graphgic); 
     values[i] = v; 
    } 

}