Question

我有两个活动，第一个请求用户在EditText中输入数据，然后用户按下按钮，该值保存在SQLite数据库中，并显示在第二个活动TextView中。

除了在TextView中显示它我还希望它作为一个点显示在Graph中，但不知道如何做到这一点。图中的点是Float，当我尝试将TextView结果转换为float时，它就不会工作了。

无论如何，这是java文件的代码（第二个活动）：

public class StatistikaGrafoviMain extends AppCompatActivity {


    EditText buckysInput;
    TextView buckysText;
    StatistikeInputTezinaHelper dbHandler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_statistika_grafovi_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        buckysInput = (EditText) findViewById(R.id.buckysInput);
        buckysText = (TextView) findViewById(R.id.buckysText);
        dbHandler = new StatistikeInputTezinaHelper(this, null, null, 1);
        printDatabase();

        ValueLineChart mCubicValueLineChart = (ValueLineChart) findViewById(R.id.cubiclinechart);

        ValueLineSeries series = new ValueLineSeries();
        series.setColor(0xFF56B7F1);

// HERE ARE THE POINTS - THESE ARE JUST DEFAULT ONES, DON'T MIND THEM
        series.addPoint(new ValueLinePoint("Jan", 2.4f));
        series.addPoint(new ValueLinePoint("Feb", 3.4f));
        series.addPoint(new ValueLinePoint("Mar", .4f));
        series.addPoint(new ValueLinePoint("Apr", 1.2f));
        series.addPoint(new ValueLinePoint("Mai", 2.6f));
        series.addPoint(new ValueLinePoint("Jun", 1.0f));
        series.addPoint(new ValueLinePoint("Jul", 3.5f));
        series.addPoint(new ValueLinePoint("Aug", 2.4f));
        series.addPoint(new ValueLinePoint("Sep", 2.4f));
        series.addPoint(new ValueLinePoint("Oct", 3.4f));
        series.addPoint(new ValueLinePoint("Nov", .4f));
        series.addPoint(new ValueLinePoint("Dec", 1.3f));

        mCubicValueLineChart.addSeries(series);
        mCubicValueLineChart.startAnimation();

    }
    //Add a product to the database
    public void addButtonClicked(View view){
        Product product = new Product(buckysInput.getText().toString());
        dbHandler.addProduct(product);
        printDatabase();
    }

    //Delete items
    public void deleteButtonClicked(View view){
        String inputText = buckysInput.getText().toString();
        dbHandler.deleteProduct(inputText);
        printDatabase();
    }

    //Print the database
    public void printDatabase(){
        String dbString = dbHandler.databaseToString();
        buckysText.setText(dbString);
        buckysInput.setText("");
    }

}

如果您需要我发布一些额外的代码，请在下面写一下。

谢谢！

修改

 public String databaseToString(){
        String dbString = "";
        SQLiteDatabase db = getWritableDatabase();
        String query = "SELECT * FROM " + TABLE_PRODUCTS + " WHERE 1";

        //Cursor points to a location in your results
        Cursor c = db.rawQuery(query, null);
        //Move to the first row in your results
        c.moveToFirst();

        //Position after the last row means the end of the results
        while (!c.isAfterLast()) {
            if (c.getString(c.getColumnIndex("productname")) != null) {
                dbString += c.getString(c.getColumnIndex("productname"));
                dbString += "\n";
            }
            c.moveToNext();
        }
        db.close();
        return dbString;
    }

Answer 1

如果你想从一个点到另一个点绘制线条，你可以扩展textview或imageview，然后覆盖onDraw（Canvas canvas），canvas.drawLine（），你可以解决问题

在Graph上打印SQLite数据库数据

1 个答案: