AnasLmt AnasLmt - 5 months ago 62
Android Question

Installing a support library for PreferenceFragmentCompat

I'm new to Android Studio and a total beginner at Android programming in general. I looked and looked and I couldn't find the right thing to do.

All I want is to install a library to use PreferenceFragmentCompat or any class that replaces android.app.PreferenceFragment so my app can work in API 11 and lower.

Can anyone please give me some details such as which library should I use and how to install it in my AS project.

Edit: So I started developing this app using

android.support.v4
and
android.support.v7
libraries to handle the Fragments so I can run it on API 11 and lower.

this is my MainActivity.java.

package com.example.myapplication;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.ActionBar;

import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {

/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;

/**
* Used to store the last screen title. For use in {@link #restoreActionBar()}.
*/
private CharSequence mTitle;

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

mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();

// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}

@Override
public void onNavigationDrawerItemSelected(int position) {
Fragment mainFragment = null;

switch(position) {
case 0: // home fragment
mainFragment = new HomeFragment();
break;
case 1: // favorites list
mainFragment = new FaveFragment();
break;
case 2: // rate app
/* visit app TODO put application package id in the link */
Intent visitStore = new Intent(Intent.ACTION_VIEW);
visitStore.setData(Uri.parse("market://details?id=com.google.android.apps.maps"));
startActivity(visitStore);
break;
case 3: // settings
mainFragment = new SettingsFragment();
break;
case 4: // about
mainFragment = new AboutFragment();
break;

}

if(position != 2) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, mainFragment)
.commit();
}
}

public void onSectionAttached(int number) {
String[] stringArray = getResources().getStringArray(R.array.section_titles);
if (number >= 1) {
mTitle = stringArray[number - 1];
}
}

public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.main, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}

@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);
}

/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";

/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}

public PlaceholderFragment() {
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}

@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}

}


Now this is my SettingsFragment.java:

package com.example.myapplication;

import android.os.Bundle;
import android.preference.PreferenceFragment;

public class SettingsFragment extends PreferenceFragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

addPreferencesFromResource(R.xml.settings);
}
}


The real problem I encounter here is with this line:
mainFragment = new SettingsFragment();
in the
onNavigationDrawerItemSelected(int position)
method in MainActivity.java.

It returns an error saying:


Error:(70, 32) error: incompatible types: SettingsFragment cannot be
converted to Fragment


How can I fix this and still be able to use my app on API 11 and lower?

Answer

After adding com.android.support:preference-v7:23.0.1 to your build.gradle file, simply change the line

public class SettingsFragment extends PreferenceFragment {

to

public class SettingsFragment extends PreferenceFragmentCompat {

The error is caused by PreferenceFragment, which extends android.app.Fragment, not android.support.v4.app.Fragment which you need, as you are using support library class.