在列表视图项上按ID打开新活动，请点击

Question

My ListView is opening and everything is ok. I don´t know how to pass params from onPostExecute() to onItemClick() to open a new activity (SingleItem.java) by id. Nothing that I´ve tried has worked.

ListItems.java

public class ListItems extends Activity {

private ListView listV;
TextView estado, cidade, noItem;

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

    listV = (ListView) findViewById(R.id.listV);

    estado = (TextView) findViewById(R.id.Estado);
    cidade = (TextView) findViewById(R.id.Cidade);
    noItem = (TextView) findViewById(R.id.noItem);

    estado.setText(getIntent().getExtras().getString("state"));     
    cidade.setText(getIntent().getExtras().getString("city"));

    Task task = new Task();
    task.execute();

    listV.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {

            Intent intent = new Intent(getApplicationContext(), SingleItem.class);

            startActivity(intent);
        }
    });
}

public class Task extends AsyncTask<String, String, Void>{

    private ProgressDialog progressDialog = new ProgressDialog(ListItems.this);

    InputStream is = null;
    String result = "";

    protected void onPreExecute() {
        progressDialog.setMessage("Listing Items...");
        progressDialog.show();
        progressDialog.setOnCancelListener(new OnCancelListener() {

            @Override
            public void onCancel(DialogInterface dialog) {
                Task.this.cancel(true);
            }
        });
    };

    @Override
    protected Void doInBackground(String... params) {

        String url = "http://myip/webviews/jsonlistItems.php";

        HttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);

        ArrayList<NameValuePair> param = new ArrayList<NameValuePair>();

        try {
            httpPost.setEntity(new UrlEncodedFormEntity(param));

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();

            is = httpEntity.getContent();

        } catch (Exception e) {
            Log.e("log_tag", "Error connecting to database " + e.toString());
            Toast.makeText(ListItems.this, "Try again.", Toast.LENGTH_LONG).show();
        }

        try
        {
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            StringBuilder sb = new StringBuilder();
            String line = "";

            while((line = br.readLine()) != null){
                sb.append(line+"\n");
            }
                is.close();
                result = sb.toString();

        }catch(Exception e){
            Log.e("log_tag", "Error converting result " + e.toString());
        }
        return null;
    }

    protected void onPostExecute(Void v){

        try {
            JSONArray Jarray = new JSONArray(result);
            for (int i = 0; i < Jarray.length(); i++) {
                JSONObject jsonObject = null;
                jsonObject = Jarray.getJSONObject(i);

                // output
                String item_id = jsonObject.getString("item_id");

                String item_name = jsonObject.getString("item_name");
                String item_color = jsonObject.getString("item_color");
                String city = jsonObject.getString("city");
                String statee = jsonObject.getString("state");

                if(estado.getText().toString().equalsIgnoreCase(statee) && 
                        cidade.getText().toString().equalsIgnoreCase(city)){

                    String[] values = new String[] {item_name, item_color};

                    ArrayAdapter<String> adapter = new ArrayAdapter<String>(ListItems.this, android.R.layout.simple_list_item_1, values);

                    listV.setAdapter(adapter);
                    break;
                }
                else{
                    noItem.setText("No Item to show");
                }
            }
            this.progressDialog.dismiss();
        } catch (Exception e) {
            Log.e("log_tag", "Error parsing data "+e.toString());
        }
    }

}


public class ItemById{

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.list_events, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}
}

SingleItem.java

public class SingleItem extends Activity {

TextView item_name, item_color;

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

    item_name = (TextView) findViewById(R.id.item_name);
    item_color = (TextView) findViewById(R.id.item_color);


}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.event, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}
}

How to pass params from onPostExecute() to onItemClick() to open a new activity (SingleItem.java) by id?

Answer 1

The adapter looks like it's populated only by each attribute of your JSON object (one row for item_name, one row for item_color). If this is what you want the naturally you won't get item_id because it's not there.

If you want each row to correspond to each of your JSON objects then you should modify your adapter.

First make your own class like so

class Wrap{
    String itemId, itemName, city, statee;
}

And then create your own Adapter class that extends ArrayAdapter<Wrap> .

This way every time a row is clicked, you can get the Wrap object which contains everything, including id. Then you can pass these values to your next Activity.

Answer 2

It all depends what your SingleItem Activity is supposed to show when it's opened. If you only need the name of the selected item then you simply retrieve the item name in the onItemClick method and pass it as parameter to SingleItem:

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    Intent intent = new Intent(getApplicationContext(), SingleItem.class);
    String name = adapter.getItem(position);
    intent.putExtra("yourItem", name);
    startActivity(intent);
}

In order for this to work the adapter needs to be a variable in the Activity:

public class ListItems extends Activity {
    private ArrayAdapter<String> adapter;

and this:

ArrayAdapter<String> adapter = new ArrayAdapter<String>(ListItems.this, android.R.layout.simple_list_item_1, values);

becomes this:

adapter = new ArrayAdapter<String>(ListItems.this, android.R.layout.simple_list_item_1, values);

If you need more information in the SingleItem Activity than just the name of the item you'd have to create an Item class to hold that information:

public static class Item implements Serializable {
    String mName;
    String mColor;
    // more data

    @Override
    public String toString() {
        return mName;
    }
}

your onItemClick becomes:

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    Intent intent = new Intent(getApplicationContext(), SingleItem.class);
    Item item = adapter.getItem(position);
    intent.putExtra("yourItem", name);
    startActivity(intent);
}

Your adapter would be:

ArrayAdapter<Item> adapter;
adapter = new ArrayAdapter<Item>(ListItems.this, android.R.layout.simple_list_item_1, itemArray);

Of course you'd need to create the itemArray when parsing the json stream.

The activity could easily read the selected item from the intent like so:

getIntent().getSerializableExtra("yourItem");