PreLoadingFragment

PreLoadingFragment.java

package /* YOUR PACKAGE HERE */;

package cc.edinteractive.visitavirtual.fragment;

import android.app.Activity;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import cc.edinteractive.visitavirtual.R;

/**
 * <p>Extend this class to have a ProgressBar initially attached to your fragment.</p>
 * <p>Do your networking or database stuff using {@link android.support.v4.app.Fragment#onStart()} or {@link android.support.v4.app.Fragment#onResume()}.
 * After you're done with them, call {@link #signalLoaded(Object)} passing the object acquired through the long request.</p>
 * @author Julio Rodrigues
 */
public abstract class PreLoadingFragment<T> extends Fragment {

	private LayoutInflater inflater;
	private ViewGroup container;
	private Bundle savedInstanceState;
	private Object internetData;
	protected Activity activity;

	@Override
	public void onAttach(Activity activity) {
		super.onAttach(activity);
		this.activity = activity;
	}
	
	@Override
	public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
		this.inflater = inflater;
		this.container = container;
		this.savedInstanceState = savedInstanceState;
		return inflater.inflate(R.layout.spaced_progress_bar, container, false).findViewById(R.id.progress_bar);
	}
	
	public abstract View onLoaded(final LayoutInflater inflater, @Nullable final ViewGroup container, @Nullable Bundle savedInstanceState, T internetData);
	
	/**
	 * Call this method when the long request is done
	 * @param internetData
	 */
	public void signalLoaded(T internetData) {
		this.internetData = internetData;
		container = removeLoader();
		container.addView(onLoaded(inflater, container, savedInstanceState, internetData));
	}
	
	/**
	 * Removes the Progress Bar. This should only be called after onCreateView()
	 * @return ViewGroup returns the fragment container view 
	 */
	private ViewGroup removeLoader() {
		ViewGroup root = (ViewGroup) getView();
		FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(
				FrameLayout.LayoutParams.MATCH_PARENT,
				FrameLayout.LayoutParams.WRAP_CONTENT
		);
		root.setLayoutParams(lp);
		root.removeView(root.findViewById(R.id.progress_bar));
		return root;
	}
	
}

spaced_progress_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<ProgressBar xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/progress_bar"
        style="?android:attr/progressBarStyleLarge"
        android:layout_gravity="center"        
        android:paddingTop="60dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />