Question:
I have a calendar about events where I live and I can already receive a list with the titles of the events through my database in Mysql and JSON. Now I wish that when I clicked on the event it would redirect to an activity with event information, but I don't know how to do that. Could you help me I'm new to android.
my code:
package com.eu.agendamarinhagrande;
import android.annotation.TargetApi;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Build;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import com.eu.agendamarinhagrande.JSONParser;
import com.eu.agendamarinhagrande.R;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.text.Normalizer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.regex.Pattern;
public class MainActivity extends ActionBarActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
// JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> empresaList;
// url to get all products list
private static String url_all_empresas = "http://www.grifin.pt/projectoamg/Conexao.php";
// JSON Node names
private static final String TAG_TITULO = "Titulo";
// products JSONArray
String resultado = null;
ListView lista;
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Hashmap para el ListView
empresaList = new ArrayList<HashMap<String, String>>();
new Download().execute();
// Cargar los productos en el Background Thread
lista = (ListView) findViewById(R.id.listView);
// ActionBar actionBar = getSupportActionBar();
// actionBar.setDisplayHomeAsUpEnabled(true);
}//fin onCreate
public class Download extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
String out = null;
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
final HttpParams httpParameters = httpClient.getParams();
HttpConnectionParams.setConnectionTimeout(httpParameters, 15000);
HttpConnectionParams.setSoTimeout(httpParameters, 15000);
HttpGet httpPost = new HttpGet(url_all_empresas);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
out = EntityUtils.toString(httpEntity, HTTP.UTF_8);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return out;
}
@TargetApi(Build.VERSION_CODES.GINGERBREAD)
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
ArrayList<String> list = new ArrayList<>();
try {
JSONArray jsonArray = new JSONArray(result);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsa = jsonArray.getJSONObject(i);
String str = jsa.getString("Titulo");
String data = jsa.getString("Datainicio");
Log.e("TAG", str);
Log.e("TAG", data);
String s1 = Normalizer.normalize(str, Normalizer.Form.NFKD);
String regex = Pattern.quote("[\\p{InCombiningDiacriticalMarks}\\p{IsLm}\\p{IsSk}]+");
str = new String(s1.replaceAll(regex, "").getBytes("ascii"), "ascii");
list.add(str+"\n"+data);
}
ArrayAdapter adapter = new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_list_item_1, list);
// updating listview
//setListAdapter(adapter);
lista.setAdapter(adapter);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
Answer:
First, if you intend to pass Objects you created between Activities , you need to implement it as Parcelable or Serializable .
Implementing your class as Parcelable or Serializable , means that you can serialize this object, i.e. write the values and structure of an object in metadata so that you can transfer it from one Activity to another, which in turn needs deserialize this object and use it properly.
An example of a class in Parcelable :
public class Exemplo implements Parcelable {
private String stringExemplo;
private int intExemplo;
private boolean booleanExemplo;
public String getStringExemplo() {
return stringExemplo;
}
public void setStringExemplo(String stringExemplo) {
this.stringExemplo = stringExemplo;
}
public int getIntExemplo() {
return intExemplo;
}
public void setIntExemplo(int intExemplo) {
this.intExemplo = intExemplo;
}
public boolean isBooleanExemplo() {
return booleanExemplo;
}
public void setBooleanExemplo(boolean booleanExemplo) {
this.booleanExemplo = booleanExemplo;
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(this.stringExemplo);
dest.writeInt(this.intExemplo);
dest.writeByte(booleanExemplo ? (byte) 1 : (byte) 0);
}
public Exemplo() {
}
protected Exemplo(Parcel in) {
this.stringExemplo = in.readString();
this.intExemplo = in.readInt();
this.booleanExemplo = in.readByte() != 0;
}
public static final Parcelable.Creator<Exemplo> CREATOR = new Parcelable.Creator<Exemplo>() {
public Exemplo createFromParcel(Parcel source) {
return new Exemplo(source);
}
public Exemplo[] newArray(int size) {
return new Exemplo[size];
}
};
}
Example of a class with Serializable :
public class Exemplo implements Serializable {
private static final long serialVersionUID = 1L;
private String stringExemplo;
private int intExemplo;
private boolean booleanExemplo;
public String getStringExemplo() {
return stringExemplo;
}
public void setStringExemplo(String stringExemplo) {
this.stringExemplo = stringExemplo;
}
public int getIntExemplo() {
return intExemplo;
}
public void setIntExemplo(int intExemplo) {
this.intExemplo = intExemplo;
}
public boolean isBooleanExemplo() {
return booleanExemplo;
}
public void setBooleanExemplo(boolean booleanExemplo) {
this.booleanExemplo = booleanExemplo;
}
}
Now that you have a serializable object, you need to capture it in the onItemClickListener() of your ListView :
lista = (ListView) findViewById(R.id.listView);
lista.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
//Capturando o objeto associado ao item da lista
Exemplo objetoExemplo = (Exemplo) adapterView.getAdapter().getItem(position);
//Caso você queira passar tipos primitivos
String stringExemplo = "Algum texto";
int intExemplo = 1;
boolean booleanExemplo = true;
Intent intent = new Intent(SuaActivity.this, SuaOutraActivity.class);
//O primeiro parametro é o nome deste extra a ser capturado na sua outra Activity
intent.putExtra("objeto_extra", objetoExemplo);
intent.putExtra("string_extra", stringExemplo);
intent.putExtra("int_extra", intExemplo);
intent.putExtra("boolean_extra", booleanExemplo);
startActivity(intent);
}
});
To capture in your other Activity :
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getIntent().getExtras() != null) {
if (getIntent().hasExtra("extra_objeto")) {
Exemplo exemplo = getIntent().getExtras().getParcelable("extra_objeto");
}
if (getIntent().hasExtra("string_extra")) {
String strintExemplo = getIntent().getExtras().getString("string_extra");
}
if (getIntent().hasExtra("int_extra")) {
int teste = getIntent().getExtras().getInt("int_extra");
}
if (getIntent().hasExtra("boolean_extra")) {
boolean booleanExemplo = getIntent().getExtras().getBoolean("boolean_extra");
}
}
}