Cannot resolve method 'add(int, com.example.**.beatle.app.MainActivity.PlaceholderFragment)

Question

package com.example.**.beatle.app;

import android.app.Fragment;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;


public class MainActivity extends FragmentActivity   {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if(savedInstanceState==null)
    {
        getSupportFragmentManager().beginTransaction().add(R.id.container, new PlaceholderFragment()).commit();
    }
}


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

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

public static class PlaceholderFragment extends Fragment {

    private ArrayAdapter<String> mForecastAdapter;


    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        String[] forecastArray = {"Today-Sunny-88/63", "Tommorrow-windy-88/94", "wed-aloo-alooo"};
        List<String> weekForecast = new ArrayList<String>(Arrays.asList(forecastArray));
        mForecastAdapter = new ArrayAdapter<String>(getActivity(), R.layout.fragment_main, R.id.list_item_forecast_textview, weekForecast);
        ListView listView = (ListView) rootView.findViewById(R.id.list_view_forecast);
        listView.setAdapter(mForecastAdapter);
        return rootView;

    }
}}

Messages Gradle Build Error:(27, 59) error: no suitable method found for add(int,PlaceholderFragment) method FragmentTransaction.add(Fragment,String) is not applicable (argument mismatch; int cannot be converted to Fragment) method FragmentTransaction.add(int,Fragment) is not applicable (argument mismatch; PlaceholderFragment cannot be converted to Fragment) Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output Error:Execution failed for task ':app:compileDebugJava'. Compilation failed; see the compiler error output for details.

Answer 1

You are using FragmentActivity and getSupportFragmentManager(). Therefore, PlaceholderFragment needs to inherit from android.support.v4.app.Fragment, not android.app.Fragment.

Answer 2

Use

 import android.support.v4.app.Fragment; 

instead of

import android.app.Fragment;

All over in the project.

Also, use support library for FragmentManager and FragmentTransaction.