Update Android java code (#7820)

Targets SDK 26 as required by the playstore.
Fixes screen auto-rotation closing game.
Hides on-screen navigation bar if present.

Update gradlew.
Fix display aspect on 18+/:9 displays (like a Samsung Galaxy S9).
Remove small app icons, not required.
Fix xml in unpacking activity.
Support Android permission: On Android 6.0+ you need to manually give write
permission (as required by google).
Background during unpacking (just a demo for now).
Material Design: no more Android 2 interface.
Immersive mode (Android 4.4+ - hide NavBar for fullscreen mode).

4 files changed, 310 insertions, 265 deletions

diff --git a/build/android/src/main/java/net.minetest.minetest/MainActivity.java b/build/android/src/main/java/net.minetest.minetest/MainActivity.java
new file mode 100644
index 000000000..1baa71668
--- /dev/null
+++ b/build/android/src/main/java/net.minetest.minetest/MainActivity.java
@@ -0,0 +1,79 @@
+package net.minetest.minetest;
+
+import android.Manifest;
+import android.app.Activity;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.os.Build;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.v4.app.ActivityCompat;
+import android.support.v4.content.ContextCompat;;
+import android.widget.Toast;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class MainActivity extends Activity {
+
+	private final static int PERMISSIONS = 1;
+	private static final String[] REQUIRED_SDK_PERMISSIONS = new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE};
+
+	@Override
+	public void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+			checkPermission();
+		} else {
+			next();
+		}
+	}
+
+	protected void checkPermission() {
+		final List<String> missingPermissions = new ArrayList<String>();
+		// check required permission
+		for (final String permission : REQUIRED_SDK_PERMISSIONS) {
+			final int result = ContextCompat.checkSelfPermission(this, permission);
+			if (result != PackageManager.PERMISSION_GRANTED) {
+				missingPermissions.add(permission);
+			}
+		}
+		if (!missingPermissions.isEmpty()) {
+			// request permission
+			final String[] permissions = missingPermissions
+					.toArray(new String[missingPermissions.size()]);
+			ActivityCompat.requestPermissions(this, permissions, PERMISSIONS);
+		} else {
+			final int[] grantResults = new int[REQUIRED_SDK_PERMISSIONS.length];
+			Arrays.fill(grantResults, PackageManager.PERMISSION_GRANTED);
+			onRequestPermissionsResult(PERMISSIONS, REQUIRED_SDK_PERMISSIONS,
+					grantResults);
+		}
+	}
+
+	@Override
+	public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[],
+										   @NonNull int[] grantResults) {
+		switch (requestCode) {
+			case PERMISSIONS:
+				for (int index = 0; index < permissions.length; index++) {
+					if (grantResults[index] != PackageManager.PERMISSION_GRANTED) {
+						// permission not granted - toast and exit
+						Toast.makeText(this, R.string.not_granted, Toast.LENGTH_LONG).show();
+						finish();
+						return;
+					}
+				}
+				// permission were granted - run
+				next();
+				break;
+		}
+	}
+
+	public void next() {
+		Intent intent = new Intent(this, MtNativeActivity.class);
+		intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_CLEAR_TASK);
+		startActivity(intent);
+	}
+}
diff --git a/build/android/src/main/java/net.minetest.minetest/MinetestAssetCopy.java b/build/android/src/main/java/net.minetest.minetest/MinetestAssetCopy.java
index eb92acb63..b570fe61a 100644
--- a/build/android/src/main/java/net.minetest.minetest/MinetestAssetCopy.java
+++ b/build/android/src/main/java/net.minetest.minetest/MinetestAssetCopy.java
@@ -1,416 +1,373 @@
 package net.minetest.minetest;
 
-import java.io.BufferedReader;
-import java.io.File;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.OutputStream;
-import java.util.Vector;
-import java.util.Iterator;
-import java.lang.Object;
-
 import android.app.Activity;
 import android.content.res.AssetFileDescriptor;
-
 import android.os.AsyncTask;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.Environment;
 import android.util.Log;
 import android.view.Display;
+import android.view.View;
 import android.widget.ProgressBar;
 import android.widget.TextView;
-import android.graphics.Rect;
-import android.graphics.Paint;
-import android.text.TextPaint;
 
-public class MinetestAssetCopy extends Activity
-{
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.util.Iterator;
+import java.util.Vector;
+
+public class MinetestAssetCopy extends Activity {
+	ProgressBar m_ProgressBar;
+	TextView m_Filename;
+	copyAssetTask m_AssetCopy;
+
 	@Override
-	public void onCreate(Bundle savedInstanceState)
-	{
+	public void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
-		
 		setContentView(R.layout.assetcopy);
-		
-		m_ProgressBar = (ProgressBar) findViewById(R.id.progressBar1);
-		m_Filename = (TextView) findViewById(R.id.textView1);
-		
+		m_ProgressBar = findViewById(R.id.progressBar1);
+		m_Filename = findViewById(R.id.textView1);
 		Display display = getWindowManager().getDefaultDisplay();
 		m_ProgressBar.getLayoutParams().width = (int) (display.getWidth() * 0.8);
 		m_ProgressBar.invalidate();
-		
+
 		/* check if there's already a copy in progress and reuse in case it is*/
-		MinetestAssetCopy prevActivity = 
+		MinetestAssetCopy prevActivity =
 				(MinetestAssetCopy) getLastNonConfigurationInstance();
-		if(prevActivity!= null) {
+		if (prevActivity != null) {
 			m_AssetCopy = prevActivity.m_AssetCopy;
-		}
-		else {
+		} else {
 			m_AssetCopy = new copyAssetTask();
 			m_AssetCopy.execute();
 		}
 	}
-	
+
+	@Override
+	protected void onResume() {
+		super.onResume();
+		makeFullScreen();
+	}
+
+	public void makeFullScreen() {
+		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+			this.getWindow().getDecorView().setSystemUiVisibility(
+					View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
+			);
+		}
+	}
+
+	@Override
+	public void onWindowFocusChanged(boolean hasFocus) {
+		super.onWindowFocusChanged(hasFocus);
+		if (hasFocus) {
+			makeFullScreen();
+		}
+	}
+
 	/* preserve asset copy background task to prevent restart of copying */
 	/* this way of doing it is not recommended for latest android version */
 	/* but the recommended way isn't available on android 2.x */
-	public Object onRetainNonConfigurationInstance()
-	{
+	public Object onRetainNonConfigurationInstance() {
 		return this;
 	}
-	
-	ProgressBar m_ProgressBar;
-	TextView m_Filename;
-	
-	copyAssetTask m_AssetCopy;
-	
-	private class copyAssetTask extends AsyncTask<String, Integer, String>
-	{
-		private long getFullSize(String filename)
-		{
+
+	private class copyAssetTask extends AsyncTask<String, Integer, String> {
+		boolean m_copy_started = false;
+		String m_Foldername = "media";
+		Vector<String> m_foldernames;
+		Vector<String> m_filenames;
+		Vector<String> m_tocopy;
+		Vector<String> m_asset_size_unknown;
+
+		private long getFullSize(String filename) {
 			long size = 0;
 			try {
 				InputStream src = getAssets().open(filename);
 				byte[] buf = new byte[4096];
-				
+
 				int len = 0;
-				while ((len = src.read(buf)) > 0)
-				{
+				while ((len = src.read(buf)) > 0) {
 					size += len;
 				}
-			}
-			catch (IOException e)
-			{
+			} catch (IOException e) {
 				e.printStackTrace();
 			}
 			return size;
 		}
 
 		@Override
-		protected String doInBackground(String... files)
-		{
-			m_foldernames  = new Vector<String>();
-			m_filenames    = new Vector<String>();
-			m_tocopy       = new Vector<String>();
+		protected String doInBackground(String... files) {
+			m_foldernames = new Vector<String>();
+			m_filenames = new Vector<String>();
+			m_tocopy = new Vector<String>();
 			m_asset_size_unknown = new Vector<String>();
-			String baseDir = 
+			String baseDir =
 					Environment.getExternalStorageDirectory().getAbsolutePath()
-					+ "/";
-			
-			
+							+ "/";
+
+
 			// prepare temp folder
 			File TempFolder = new File(baseDir + "Minetest/tmp/");
-			
-			if (!TempFolder.exists())
-			{
+
+			if (!TempFolder.exists()) {
 				TempFolder.mkdir();
-			}
-			else {
+			} else {
 				File[] todel = TempFolder.listFiles();
-				
-				for(int i=0; i < todel.length; i++)
-				{
-					Log.v("MinetestAssetCopy","deleting: " + todel[i].getAbsolutePath());
+
+				for (int i = 0; i < todel.length; i++) {
+					Log.v("MinetestAssetCopy", "deleting: " + todel[i].getAbsolutePath());
 					todel[i].delete();
 				}
 			}
-			
+
 			// add a .nomedia file
 			try {
 				OutputStream dst = new FileOutputStream(baseDir + "Minetest/.nomedia");
 				dst.close();
 			} catch (IOException e) {
-				Log.e("MinetestAssetCopy","Failed to create .nomedia file");
+				Log.e("MinetestAssetCopy", "Failed to create .nomedia file");
 				e.printStackTrace();
 			}
-			
-			
+
+
 			// build lists from prepared data
 			BuildFolderList();
 			BuildFileList();
-			
+
 			// scan filelist
 			ProcessFileList();
-			
+
 			// doing work
 			m_copy_started = true;
 			m_ProgressBar.setMax(m_tocopy.size());
-			
-			for (int i = 0; i < m_tocopy.size(); i++)
-			{
-				try
-				{
+
+			for (int i = 0; i < m_tocopy.size(); i++) {
+				try {
 					String filename = m_tocopy.get(i);
 					publishProgress(i);
-					
+
 					boolean asset_size_unknown = false;
 					long filesize = -1;
-					
-					if (m_asset_size_unknown.contains(filename))
-					{
+
+					if (m_asset_size_unknown.contains(filename)) {
 						File testme = new File(baseDir + "/" + filename);
-						
-						if(testme.exists())
-						{
+
+						if (testme.exists()) {
 							filesize = testme.length();
 						}
 						asset_size_unknown = true;
 					}
-					
+
 					InputStream src;
-					try
-					{
+					try {
 						src = getAssets().open(filename);
 					} catch (IOException e) {
-						Log.e("MinetestAssetCopy","Copying file: " + filename + " FAILED (not in assets)");
+						Log.e("MinetestAssetCopy", "Copying file: " + filename + " FAILED (not in assets)");
 						e.printStackTrace();
 						continue;
 					}
-					
+
 					// Transfer bytes from in to out
-					byte[] buf = new byte[1*1024];
+					byte[] buf = new byte[1024];
 					int len = src.read(buf, 0, 1024);
-					
+
 					/* following handling is crazy but we need to deal with    */
 					/* compressed assets.Flash chips limited livetime due to   */
 					/* write operations, we can't allow large files to destroy */
 					/* users flash.                                            */
-					if (asset_size_unknown)
-					{
-						if ( (len > 0) && (len < buf.length) && (len == filesize))
-						{
+					if (asset_size_unknown) {
+						if ((len > 0) && (len < buf.length) && (len == filesize)) {
 							src.close();
 							continue;
 						}
-						
-						if (len == buf.length)
-						{
+
+						if (len == buf.length) {
 							src.close();
 							long size = getFullSize(filename);
-							if ( size == filesize)
-							{
+							if (size == filesize) {
 								continue;
 							}
 							src = getAssets().open(filename);
 							len = src.read(buf, 0, 1024);
 						}
 					}
-					if (len > 0)
-					{
+					if (len > 0) {
 						int total_filesize = 0;
 						OutputStream dst;
-						try
-						{
+						try {
 							dst = new FileOutputStream(baseDir + "/" + filename);
 						} catch (IOException e) {
-							Log.e("MinetestAssetCopy","Copying file: " + baseDir +
-							"/" + filename + " FAILED (couldn't open output file)");
+							Log.e("MinetestAssetCopy", "Copying file: " + baseDir +
+									"/" + filename + " FAILED (couldn't open output file)");
 							e.printStackTrace();
 							src.close();
 							continue;
 						}
 						dst.write(buf, 0, len);
 						total_filesize += len;
-						
-						while ((len = src.read(buf)) > 0)
-						{
+
+						while ((len = src.read(buf)) > 0) {
 							dst.write(buf, 0, len);
 							total_filesize += len;
 						}
-						
+
 						dst.close();
-						Log.v("MinetestAssetCopy","Copied file: " +
-									m_tocopy.get(i) + " (" + total_filesize +
-									" bytes)");
-					}
-					else if (len < 0)
-					{
-						Log.e("MinetestAssetCopy","Copying file: " +
+						Log.v("MinetestAssetCopy", "Copied file: " +
+								m_tocopy.get(i) + " (" + total_filesize +
+								" bytes)");
+					} else if (len < 0) {
+						Log.e("MinetestAssetCopy", "Copying file: " +
 								m_tocopy.get(i) + " failed, size < 0");
 					}
 					src.close();
-				} 
-				catch (IOException e)
-				{
-					Log.e("MinetestAssetCopy","Copying file: " +
+				} catch (IOException e) {
+					Log.e("MinetestAssetCopy", "Copying file: " +
 							m_tocopy.get(i) + " failed");
 					e.printStackTrace();
 				}
 			}
 			return "";
 		}
-		
-		
+
 		/**
 		 * update progress bar
 		 */
-		protected void onProgressUpdate(Integer... progress)
-		{
-			
-			if (m_copy_started)
-			{
+		protected void onProgressUpdate(Integer... progress) {
+
+			if (m_copy_started) {
 				boolean shortened = false;
 				String todisplay = m_tocopy.get(progress[0]);
 				m_ProgressBar.setProgress(progress[0]);
 				m_Filename.setText(todisplay);
-			}
-			else
-			{
+			} else {
 				boolean shortened = false;
 				String todisplay = m_Foldername;
 				String full_text = "scanning " + todisplay + " ...";
 				m_Filename.setText(full_text);
 			}
 		}
-		
+
 		/**
-		 * check al files and folders in filelist
+		 * check all files and folders in filelist
 		 */
-		protected void ProcessFileList()
-		{
-			String FlashBaseDir = 
+		protected void ProcessFileList() {
+			String FlashBaseDir =
 					Environment.getExternalStorageDirectory().getAbsolutePath();
-			
+
 			Iterator itr = m_filenames.iterator();
-			
-			while (itr.hasNext())
-			{
+
+			while (itr.hasNext()) {
 				String current_path = (String) itr.next();
 				String FlashPath = FlashBaseDir + "/" + current_path;
-				
-				if (isAssetFolder(current_path))
-				{
+
+				if (isAssetFolder(current_path)) {
 					/* store information and update gui */
 					m_Foldername = current_path;
 					publishProgress(0);
-					
+
 					/* open file in order to check if it's a folder */
 					File current_folder = new File(FlashPath);
-					if (!current_folder.exists())
-					 {
-						if (!current_folder.mkdirs())
-						{
-							Log.e("MinetestAssetCopy","\t failed create folder: " +
+					if (!current_folder.exists()) {
+						if (!current_folder.mkdirs()) {
+							Log.e("MinetestAssetCopy", "\t failed create folder: " +
 									FlashPath);
-						}
-						else
-						{
-							Log.v("MinetestAssetCopy","\t created folder: " +
+						} else {
+							Log.v("MinetestAssetCopy", "\t created folder: " +
 									FlashPath);
 						}
 					}
-					
+
 					continue;
 				}
-				
+
 				/* if it's not a folder it's most likely a file */
 				boolean refresh = true;
-				
+
 				File testme = new File(FlashPath);
-				
+
 				long asset_filesize = -1;
 				long stored_filesize = -1;
-				
-				if (testme.exists())
-				{
-					try
-					{
+
+				if (testme.exists()) {
+					try {
 						AssetFileDescriptor fd = getAssets().openFd(current_path);
-						asset_filesize         = fd.getLength();
+						asset_filesize = fd.getLength();
 						fd.close();
-					} 
-					catch (IOException e)
-					{
+					} catch (IOException e) {
 						refresh = true;
 						m_asset_size_unknown.add(current_path);
-						Log.e("MinetestAssetCopy","Failed to open asset file \"" +
+						Log.e("MinetestAssetCopy", "Failed to open asset file \"" +
 								FlashPath + "\" for size check");
 					}
-					
+
 					stored_filesize = testme.length();
-					
-					if (asset_filesize == stored_filesize)
-					{
+
+					if (asset_filesize == stored_filesize) {
 						refresh = false;
 					}
-					
+
 				}
-				
-				if (refresh)
-				{
+
+				if (refresh) {
 					m_tocopy.add(current_path);
 				}
 			}
 		}
-		
+
 		/**
 		 * read list of folders prepared on package build
 		 */
-		protected void BuildFolderList()
-		{
-			try
-			{
+		protected void BuildFolderList() {
+			try {
 				InputStream is = getAssets().open("index.txt");
 				BufferedReader reader = new BufferedReader(new InputStreamReader(is));
-		
+
 				String line = reader.readLine();
-				while (line != null)
-				{
+				while (line != null) {
 					m_foldernames.add(line);
 					line = reader.readLine();
 				}
 				is.close();
-			} catch (IOException e1)
-			{
-				Log.e("MinetestAssetCopy","Error on processing index.txt");
+			} catch (IOException e1) {
+				Log.e("MinetestAssetCopy", "Error on processing index.txt");
 				e1.printStackTrace();
 			}
 		}
-		
+
 		/**
 		 * read list of asset files prepared on package build
 		 */
-		protected void BuildFileList()
-		{
+		protected void BuildFileList() {
 			long entrycount = 0;
-			try
-			{
+			try {
 				InputStream is = getAssets().open("filelist.txt");
 				BufferedReader reader = new BufferedReader(new InputStreamReader(is));
-		
+
 				String line = reader.readLine();
-				while (line != null)
-				{
+				while (line != null) {
 					m_filenames.add(line);
 					line = reader.readLine();
-					entrycount ++;
+					entrycount++;
 				}
 				is.close();
-			}
-			catch (IOException e1)
-			{
-				Log.e("MinetestAssetCopy","Error on processing filelist.txt");
+			} catch (IOException e1) {
+				Log.e("MinetestAssetCopy", "Error on processing filelist.txt");
 				e1.printStackTrace();
 			}
 		}
-		
-		protected void onPostExecute (String result)
-		{
+
+		protected void onPostExecute(String result) {
 			finish();
 		}
-		
-		protected boolean isAssetFolder(String path)
-		{
+
+		protected boolean isAssetFolder(String path) {
 			return m_foldernames.contains(path);
 		}
-		
-		boolean m_copy_started = false;
-		String m_Foldername = "media";
-		Vector<String> m_foldernames;
-		Vector<String> m_filenames;
-		Vector<String> m_tocopy;
-		Vector<String> m_asset_size_unknown;
 	}
 }
diff --git a/build/android/src/main/java/net.minetest.minetest/MinetestTextEntry.java b/build/android/src/main/java/net.minetest.minetest/MinetestTextEntry.java
index 68dc73274..4cd899025 100644
--- a/build/android/src/main/java/net.minetest.minetest/MinetestTextEntry.java
+++ b/build/android/src/main/java/net.minetest.minetest/MinetestTextEntry.java
@@ -6,63 +6,59 @@ import android.content.DialogInterface;
 import android.content.Intent;
 import android.os.Bundle;
 import android.text.InputType;
-import android.util.Log;
 import android.view.KeyEvent;
 import android.view.View;
 import android.view.View.OnKeyListener;
 import android.widget.EditText;
 
 public class MinetestTextEntry extends Activity {
+	private final int MultiLineTextInput = 1;
+	private final int SingleLineTextInput = 2;
+	private final int SingleLinePasswordInput = 3;
 	public AlertDialog mTextInputDialog;
 	public EditText mTextInputWidget;
-	
-	private final int MultiLineTextInput              = 1;
-	private final int SingleLineTextInput             = 2;
-	private final int SingleLinePasswordInput         = 3;
-	
+
 	@Override
 	public void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
-		
 		Bundle b = getIntent().getExtras();
 		String acceptButton = b.getString("EnterButton");
-		String hint         = b.getString("hint");
-		String current      = b.getString("current");
-		int    editType     = b.getInt("editType");
-		
+		String hint = b.getString("hint");
+		String current = b.getString("current");
+		int editType = b.getInt("editType");
+
 		AlertDialog.Builder builder = new AlertDialog.Builder(this);
 		mTextInputWidget = new EditText(this);
 		mTextInputWidget.setHint(hint);
 		mTextInputWidget.setText(current);
 		mTextInputWidget.setMinWidth(300);
 		if (editType == SingleLinePasswordInput) {
-			mTextInputWidget.setInputType(InputType.TYPE_CLASS_TEXT | 
+			mTextInputWidget.setInputType(InputType.TYPE_CLASS_TEXT |
 					InputType.TYPE_TEXT_VARIATION_PASSWORD);
-		}
-		else {
+		} else {
 			mTextInputWidget.setInputType(InputType.TYPE_CLASS_TEXT);
 		}
-		
-		
+
 		builder.setView(mTextInputWidget);
-		
+
 		if (editType == MultiLineTextInput) {
 			builder.setPositiveButton(acceptButton, new DialogInterface.OnClickListener() {
-				public void onClick(DialogInterface dialog, int whichButton) 
-				{ pushResult(mTextInputWidget.getText().toString()); }
-				});
+				public void onClick(DialogInterface dialog, int whichButton) {
+					pushResult(mTextInputWidget.getText().toString());
+				}
+			});
 		}
-		
+
 		builder.setOnCancelListener(new DialogInterface.OnCancelListener() {
 			public void onCancel(DialogInterface dialog) {
 				cancelDialog();
 			}
 		});
-		
+
 		mTextInputWidget.setOnKeyListener(new OnKeyListener() {
 			@Override
 			public boolean onKey(View view, int KeyCode, KeyEvent event) {
-				if ( KeyCode == KeyEvent.KEYCODE_ENTER){
+				if (KeyCode == KeyEvent.KEYCODE_ENTER) {
 
 					pushResult(mTextInputWidget.getText().toString());
 					return true;
@@ -70,19 +66,19 @@ public class MinetestTextEntry extends Activity {
 				return false;
 			}
 		});
-		
+
 		mTextInputDialog = builder.create();
 		mTextInputDialog.show();
 	}
-	
+
 	public void pushResult(String text) {
 		Intent resultData = new Intent();
 		resultData.putExtra("text", text);
-		setResult(Activity.RESULT_OK,resultData);
+		setResult(Activity.RESULT_OK, resultData);
 		mTextInputDialog.dismiss();
 		finish();
 	}
-	
+
 	public void cancelDialog() {
 		setResult(Activity.RESULT_CANCELED);
 		mTextInputDialog.dismiss();
diff --git a/build/android/src/main/java/net.minetest.minetest/MtNativeActivity.java b/build/android/src/main/java/net.minetest.minetest/MtNativeActivity.java
index dd611158f..f76634c20 100644
--- a/build/android/src/main/java/net.minetest.minetest/MtNativeActivity.java
+++ b/build/android/src/main/java/net.minetest.minetest/MtNativeActivity.java
@@ -2,23 +2,55 @@ package net.minetest.minetest;
 
 import android.app.NativeActivity;
 import android.content.Intent;
+import android.os.Build;
 import android.os.Bundle;
-import android.util.Log;
+import android.view.View;
 import android.view.WindowManager;
 
 public class MtNativeActivity extends NativeActivity {
+
+	static {
+		System.loadLibrary("openal");
+		System.loadLibrary("ogg");
+		System.loadLibrary("vorbis");
+		System.loadLibrary("gmp");
+		System.loadLibrary("iconv");
+		System.loadLibrary("minetest");
+	}
+
+	private int m_MessagReturnCode;
+	private String m_MessageReturnValue;
+
+	public static native void putMessageBoxResult(String text);
+
 	@Override
 	public void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 		getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
 		m_MessagReturnCode = -1;
 		m_MessageReturnValue = "";
+	}
+
+	@Override
+	protected void onResume() {
+		super.onResume();
+		makeFullScreen();
+	}
 
+	public void makeFullScreen() {
+		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+			this.getWindow().getDecorView().setSystemUiVisibility(
+					View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
+			);
+		}
 	}
 
 	@Override
-	public void onDestroy() {
-		super.onDestroy();
+	public void onWindowFocusChanged(boolean hasFocus) {
+		super.onWindowFocusChanged(hasFocus);
+		if (hasFocus) {
+			makeFullScreen();
+		}
 	}
 
 	public void copyAssets() {
@@ -27,7 +59,7 @@ public class MtNativeActivity extends NativeActivity {
 	}
 
 	public void showDialog(String acceptButton, String hint, String current,
-			int editType) {
+						   int editType) {
 
 		Intent intent = new Intent(this, MinetestTextEntry.class);
 		Bundle params = new Bundle();
@@ -38,11 +70,9 @@ public class MtNativeActivity extends NativeActivity {
 		intent.putExtras(params);
 		startActivityForResult(intent, 101);
 		m_MessageReturnValue = "";
-		m_MessagReturnCode   = -1;
+		m_MessagReturnCode = -1;
 	}
 
-	public static native void putMessageBoxResult(String text);
-
 	/* ugly code to workaround putMessageBoxResult not beeing found */
 	public int getDialogState() {
 		return m_MessagReturnCode;
@@ -67,32 +97,15 @@ public class MtNativeActivity extends NativeActivity {
 
 	@Override
 	protected void onActivityResult(int requestCode, int resultCode,
-			Intent data) {
+									Intent data) {
 		if (requestCode == 101) {
 			if (resultCode == RESULT_OK) {
 				String text = data.getStringExtra("text");
 				m_MessagReturnCode = 0;
 				m_MessageReturnValue = text;
-			}
-			else {
+			} else {
 				m_MessagReturnCode = 1;
 			}
 		}
 	}
-
-	static {
-		System.loadLibrary("openal");
-		System.loadLibrary("ogg");
-		System.loadLibrary("vorbis");
-		System.loadLibrary("gmp");
-		System.loadLibrary("iconv");
-
-		// We don't have to load libminetest.so ourselves,
-		// but if we do, we get nicer logcat errors when
-		// loading fails.
-		System.loadLibrary("minetest");
-	}
-
-	private int m_MessagReturnCode;
-	private String m_MessageReturnValue;
 }