Question

我目前正在开发一个Android项目，我希望能够按下一个按钮，它会将用户数据显示在另一个活动的列表视图中。我目前在某种意义上工作，但它需要我按两个按钮。一个从mysql数据库中获取json数据，另一个然后将其发送到下一个活动，允许我显示它。

我希望有一种方法可以通过一次单击按钮来运行这两种方法，或者在一种方法中同时使用这两种方法。

public class MyMainActivity extends AppCompatActivity {


String url = "http://192.168.20.120";
String json_string;
View v;

//Button to get the data
ImageButton getUserDetailsBtn;

//Button to parse the data
ImageButton parseUserDetailsBtn;

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

    getUserDetailsBtn= (ImageButton)findViewById(R.id.getUserDetailsButton);        

    parseUserDetailsBtn = (ImageButton)findViewById(R.id.parseUserDetailsButton);   

    getUserDetailsBtn.setVisibility(View.GONE); 


}


//
//get user details in app
//
public void getDetails(View view)  {

    new LoadUserDetails().execute();



    parseUserDetailsBtn .setVisibility(View.GONE);
    getUserDetailsBtn= .setVisibility(View.VISIBLE);



}




//Load the user details
class LoadUserDetails extends AsyncTask<Void,Void,String>
{

    String json_url;
    String JSON_STRING;

    @Override
    protected void onPreExecute() {

        json_url = url+"/getUserDetails.php";
    }

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

        try{

            URL url = new URL(json_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder = new StringBuilder();


            while((JSON_STRING = bufferedReader.readLine())!=null)
            {

                stringBuilder.append(JSON_STRING+"\n");
            }

            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return stringBuilder.toString().trim();

        } catch (MalformedJsonException e){
            e.printStackTrace();
        } catch (IOException e){
            e.printStackTrace();
        }



        return null;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
    }


    @Override
    protected void onPostExecute(String result) {
        TextView textview = (TextView) findViewById(R.id.textview);
        textview.setText("");
        json_string = result;

    }
}




//
//parse the data
//
public void parseJSON(View view)
{

    if(json_string==null){
        Toast.makeText(getApplicationContext(), "First get JSON Data", Toast.LENGTH_LONG).show();

    }
    else{
        Intent intent = new Intent(this, ShowUserActivity.class);
        intent.putExtra("json_data", json_string);
        startActivity(intent);

    }


}

Answer 1

从Activity开始onPostExecute，因为onPostExecute在UI帖子上执行

  @Override
    protected void onPostExecute(String result) {
        TextView textview = (TextView) findViewById(R.id.textview);
        textview.setText("");
        json_string = result;
        if(json_string==null){
            Toast.makeText(getApplicationContext(), "First get JSON Data",     Toast.LENGTH_LONG).show();    
        }
        else{
            Intent intent = new Intent(MyMainActivity.this, ShowUserActivity.class);
            // and change this to MyMainActivity.this
            // this will point to your task instead of Activity
            intent.putExtra("json_data", json_string);
            startActivity(intent);    
        }    
    }

Android：获取并将json数据解析为列表视图

1 个答案: