您好我有以下示例如何从数据库中提取数据以放入折线图。我有两个字段，total是double，asup是整数。我想显示两行，一行为总数，另一行为asup。 当我运行它，它变成了空白屏幕，但应用程序不会崩溃。而我的表现看起来很好。 如何在线图中显示双线和整数数据？
我的图表类
public class DbGraph2 extends Activity{
public DbGraph2(){
super();
}
private View mChart;
private String[] mililiter = new String[] {
"1000","1250","1500","1750","2000","2250","2500","2750","3000","3250","3500","3750","4000"
};
private static final String TAG = DbGraph2.class.getSimpleName();
// database configuration
// if you want the onUpgrade to run then change the database_version
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "HasilAsupan.db";
// table configuration
private static final String TABLE_NAME = "AsupanAir"; // Table name
private static final String HASIL_COLUMN_ID = "_id"; // a column named "_id" is required for cursor
private static final String HASIL_COLUMN_BBI = "hasil_BBI";
private static final String HASIL_COLUMN_TOTAL = "hasil_Total";
private static final String HASIL_COLUMN_LITER = "hasil_Liter";
private static final String HASIL_COLUMN_ASUP = "Jumlah_Asupan";
private DatabaseOpenHelper openHelper;
private SQLiteDatabase database;
private Context c;
private XYSeries series2;
private static Context aContext;
public DbGraph2(Context aContext) {
aContext = c;
openHelper = new DatabaseOpenHelper(aContext);
database = openHelper.getWritableDatabase();
}
public void insertData (String bbi, String total, String liter, String asup) {
// we are using ContentValues to avoid sql format errors
ContentValues contentValues = new ContentValues();
contentValues.put(HASIL_COLUMN_BBI, bbi);
contentValues.put(HASIL_COLUMN_TOTAL, total);
contentValues.put(HASIL_COLUMN_LITER, liter);
contentValues.put(HASIL_COLUMN_ASUP, asup);
database.insert(TABLE_NAME, null, contentValues);
}
public Cursor getAllData () {
String buildSQL = "SELECT * FROM " + TABLE_NAME;
Log.d(TAG, "getAllData SQL: " + buildSQL);
return database.rawQuery(buildSQL, null);
}
// this DatabaseOpenHelper class will actually be used to perform database related operation
private class DatabaseOpenHelper extends SQLiteOpenHelper {
public DatabaseOpenHelper(Context aContext) {
super(aContext, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
// Create your tables here
String buildSQL = "CREATE TABLE " + TABLE_NAME + "( " + HASIL_COLUMN_ID + " INTEGER PRIMARY KEY, " +
HASIL_COLUMN_BBI + " INTEGER, " + HASIL_COLUMN_TOTAL + " REAL, " + HASIL_COLUMN_LITER+"NUMERIC,"+HASIL_COLUMN_ASUP+" INTEGER )";
Log.d(TAG, "onCreate SQL: " + buildSQL);
sqLiteDatabase.execSQL(buildSQL);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
// Database schema upgrade code goes here
String buildSQL = "DROP TABLE IF EXISTS " + TABLE_NAME;
Log.d(TAG, "onUpgrade SQL: " + buildSQL);
sqLiteDatabase.execSQL(buildSQL); // drop previous table
onCreate(sqLiteDatabase); // create the table from the beginning
}
}
public String geTotalID() {
String[] column = new String[] {HASIL_COLUMN_ID};
Cursor c = database.query(TABLE_NAME, column, null,null,null,null,null);
String result ="";
int iID = c.getColumnIndex(HASIL_COLUMN_ID);
for (c.moveToFirst(); ! c.isAfterLast(); c.moveToNext()) {
result = result + c.getString(iID);
}
return result;
}
public String getTotal() {
String[] column = new String[] {HASIL_COLUMN_TOTAL};
Cursor c = database.query(TABLE_NAME,column,null,null,null,null,null);
String result = "";
int iTotal = c.getColumnIndex(HASIL_COLUMN_TOTAL);
for (c.moveToFirst(); ! c.isAfterLast(); c.moveToNext()) {
result = result + c.getString(iTotal);
}
return result;
}
public String getAsup () {
String[] column = new String[] {HASIL_COLUMN_ASUP};
Cursor c = database.query(TABLE_NAME,column, null,null,null,null,null);
String result = "";
int iAsup = c.getColumnIndex(HASIL_COLUMN_ASUP);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
result = result + c.getString(iAsup);
}
return result;
}
public void updateEntry (long id, String total, String asup) {
ContentValues cvUpdate = new ContentValues();
cvUpdate.put(HASIL_COLUMN_TOTAL, total);
cvUpdate.put(HASIL_COLUMN_ASUP, asup);
database.update(TABLE_NAME, cvUpdate, HASIL_COLUMN_ID + "= ", null);
}
public String getTotal (long id) {
return null;
}
public String getAsup (long id) {
return null;
}
public XYMultipleSeriesDataset getDemoDataSet (String title){
String[] column = new String[] {HASIL_COLUMN_TOTAL};
Cursor c = database.query(TABLE_NAME,column,null,null,null,null,null);
XYMultipleSeriesDataset dataset = new XYMultipleSeriesDataset();
XYSeries series = new XYSeries("line1");
XYSeries series2 = new XYSeries(title);
getTotal();
while (! c.isAfterLast()) {
int total = c.getInt((int) c.getColumnIndexOrThrow("total"));
int asup = c.getInt((int) c.getColumnIndexOrThrow("asup"));
series2.add(total, asup);
c.moveToNext();
}
c.close();
dataset.addSeries(series);
dataset.addSeries(series2);
return dataset;
}
public Intent getIntent (Context content) {
// Creating a dataset to hold each series
XYMultipleSeriesDataset dataset = getDemoDataSet("line1");
XYMultipleSeriesRenderer multiRenderer = new XYMultipleSeriesRenderer();
// Creating XYSeriesRenderer to customize incomeSeries
XYSeriesRenderer incomeRenderer = new XYSeriesRenderer();
incomeRenderer.setColor(Color.WHITE);
incomeRenderer.setPointStyle(PointStyle.CIRCLE);
incomeRenderer.setFillPoints(true);
incomeRenderer.setLineWidth(2);
incomeRenderer.setDisplayChartValues(true);
// Creating XYSeriesRenderer to customize expenseSeries
XYSeriesRenderer expenseRenderer = new XYSeriesRenderer();
expenseRenderer.setColor(Color.YELLOW);
expenseRenderer.setPointStyle(PointStyle.CIRCLE);
expenseRenderer.setFillPoints(true);
expenseRenderer.setLineWidth(2);
expenseRenderer.setDisplayChartValues(true);
multiRenderer.addSeriesRenderer(incomeRenderer);
// Creating a XYMultipleSeriesRenderer to customize the whole chart
multiRenderer.setXLabels(0);
multiRenderer.setChartTitle("Income vs Expense Chart");
multiRenderer.setXTitle("Year 2012");
multiRenderer.setYTitle("Amount in Dollars");
multiRenderer.setZoomButtonsVisible(true);
multiRenderer.addSeriesRenderer(expenseRenderer);
Intent intent = ChartFactory.getLineChartIntent(getBaseContext(), dataset, multiRenderer,"asfsf");
// Getting a reference to LinearLayout of the MainActivity Layout
LinearLayout chartContainer = (LinearLayout) findViewById(R.id.chart_containeer);
// Creating a Line Chart
// mChart = ChartFactory.getLineChartView(getBaseContext(), dataset, multiRenderer);
// Adding the Line Chart to the LinearLayout
// chartContainer.addView(mChart);
return intent;
}
}
清单：
<activity
android:name="com.example.perhitunganasupancairantubuh.DbGraph2"
android:label="@string/title_activity_menu_grafik" >
<intent-filter >
<action android:name="android.intent.action.View"/>
</intent-filter>
</activity>