问题
I can't get data from MySQL database for graphics. I found an example code for create graph but I want to put x axis data and y axis data from database
My example codes are:
public class Graph extends Activity {
private XYPlot xyPlot;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.graph);
// initialize our XYPlot reference:
xyPlot = (XYPlot) findViewById(R.id.xyplot);
Number[] income = {2000, 2500, 2700, 3000, 2800, 3500, 3700, 3800 };
Number[] expense = {2200, 2700, 2900, 2800, 2600, 3000, 3300, 3400 };
final String[] mMonths = new String[] {
"Jan","Feb", "Mar","Apr", "May","Jun",
"Jul", "Aug","Sep","Oct", "Nov","Dec"
};
// Converting the above income array into XYSeries
XYSeries incomeSeries = new SimpleXYSeries(
Arrays.asList(income), // array => list
SimpleXYSeries.ArrayFormat.Y_VALS_ONLY , // Y_VALS_ONLY means use the element index as the x value
"Income"); // Title of this series
// Converting the above expense array into XYSeries
XYSeries expenseSeries = new SimpleXYSeries(
Arrays.asList(expense), // array => list
SimpleXYSeries.ArrayFormat.Y_VALS_ONLY, // Y_VALS_ONLY means use the element index as the x value
"Expense"); // Title of this series
// Create a formatter to format Line and Point of income series
LineAndPointFormatter incomeFormat = new LineAndPointFormatter(
Color.rgb(0, 0, 255), // line color
Color.rgb(200, 200, 200), // point color
null ); // fill color (none)
// Create a formatter to format Line and Point of expense series
LineAndPointFormatter expenseFormat = new LineAndPointFormatter(
Color.rgb(255, 0, 0), // line color
Color.rgb(200, 200, 200), // point color
null); // fill color (none)
// add expense series to the xyplot:
xyPlot.addSeries(expenseSeries,expenseFormat);
// add income series to the xyplot:
xyPlot.addSeries(incomeSeries, incomeFormat);
// Formatting the Domain Values ( X-Axis )
xyPlot.setDomainValueFormat(new Format() {
@Override
public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {
return new StringBuffer( mMonths[ ( (Number)obj).intValue() ] );
}
@Override
public Object parseObject(String source, ParsePosition pos) {
return null;
}
});
xyPlot.setDomainLabel("");
xyPlot.setRangeLabel("Amount in Dollars");
// Increment X-Axis by 1 value
xyPlot.setDomainStep(XYStepMode.INCREMENT_BY_VAL, 1);
xyPlot.getGraphWidget().setRangeLabelWidth(50);
// Reduce the number of range labels
xyPlot.setTicksPerRangeLabel(2);
// Reduce the number of domain labels
xyPlot.setTicksPerDomainLabel(2);
// Remove all the developer guides from the chart
xyPlot.disableAllMarkup();
}
Get Database Codes:
public class AllProductsActivity extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> productsList;
// url to get all products list
private static String url_all_products = "http://10.0.2.2/android_connect/get_all_products.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_DEGERLER = "degerler";
private static final String TAG_SICAKLIK = "Sicaklik";
private static final String TAG_GERILIM = "Gerilim";
private static final String TAG_AKIM = "Akim";
private static final String TAG_REEL = "Reel Guc";
private static final String TAG_REAKTIF = "Reaktif Guc";
// products JSONArray
JSONArray products = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_products);
// Hashmap for ListView
productsList = new ArrayList<HashMap<String, String>>();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
// Check your log cat for JSON response
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_DEGERLER);
// looping through All Products
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String sicaklik = c.getString(TAG_SICAKLIK);
String gerilim = c.getString(TAG_GERILIM);
String akim = c.getString(TAG_AKIM);
String reel = c.getString(TAG_REEL);
String reaktif = c.getString(TAG_REAKTIF);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_SICAKLIK, sicaklik);
map.put(TAG_GERILIM, gerilim);
map.put(TAG_AKIM, akim);
map.put(TAG_REEL, reel);
map.put(TAG_REAKTIF, reaktif);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
}
} catch (JSONException e) {
e.printStackTrace();
}
ListAdapter adapter = new SimpleAdapter(
AllProductsActivity.this, productsList,
R.layout.list_item, new String[] { TAG_SICAKLIK,
TAG_GERILIM,TAG_AKIM,TAG_REEL,TAG_REAKTIF},
new int[] { R.id.sicaklik, R.id.gerilim, R.id.akim, R.id.reel, R.id.reaktif});
// updating listview
setListAdapter(adapter);
}
}
JSON Parser Codes:
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET method
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
回答1:
Yeah, this just isn't going to work. Activity.onCreate is not main(). You can't just put your application there.
I'm sure this isn't what you want to hear, by you really need to go all the way back to the drawing board. You are going to want to put the code that requests the JSON object into a Service.
The code that does the actual graphing looks pretty good. You will need to set it up so that when the Service succeeds in retrieving the JSON, and then parsing it, it notifies the Activity that there is something to graph.
Step back from the code and brush up on Android architecture for a couple days. It isn't hard, but it is different.
回答2:
Yes.It will be possible. you can follow my example
Bar Chart in Android With out any Built in jars. Here you can get data from database and try to set the results in the arrays(Say grossSal,netSal,datelabel arrays)
Here is the simple logic with no jars needed. you can implement bar charts with your own coding from this example
来源：https://stackoverflow.com/questions/16532415/how-to-display-graph-in-android-using-mysql-database