Real help screen (#589)

* the manual is converted from markdown to HTML during build time

* The user manual is now included in the application. The Help section will no longer attempt to open it from Github

* fixed punctuation mistakes in the manual

app/src/main/AndroidManifest.xml

@@ -28,7 +28,9 @@
 			<meta-data android:name="android.view.im" android:resource="@xml/method"/>
 		</service>
 
-		<activity android:label="@string/app_name_short" android:name="io.github.sspanak.tt9.preferences.PreferencesActivity"
+		<activity
+			android:label="@string/app_name_short"
+			android:name="io.github.sspanak.tt9.preferences.PreferencesActivity"
 			android:exported="true">
 			<intent-filter>
 				<action android:name="android.intent.action.MAIN"/>
@@ -42,6 +44,16 @@
 			android:name="io.github.sspanak.tt9.ui.dialogs.PopupDialogActivity"
 			android:theme="@style/alertDialog" />
 
+		<activity
+			android:label="@string/pref_help"
+			android:name="io.github.sspanak.tt9.preferences.HelpActivity"
+			android:exported="true">
+			<intent-filter>
+				<action android:name="android.intent.action.VIEW" />
+				<category android:name="android.intent.category.DEFAULT" />
+			</intent-filter>
+		</activity>
+
 		<activity
 			android:excludeFromRecents="true"
 			android:label=""

app/src/main/java/io/github/sspanak/tt9/preferences/HelpActivity.java

@@ -0,0 +1,76 @@
+package io.github.sspanak.tt9.preferences;
+
+import android.content.res.AssetManager;
+import android.os.Bundle;
+import android.util.Base64;
+import android.webkit.WebView;
+
+import androidx.annotation.Nullable;
+import androidx.appcompat.app.ActionBar;
+import androidx.appcompat.app.AppCompatActivity;
+
+import java.io.BufferedReader;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+
+import io.github.sspanak.tt9.R;
+import io.github.sspanak.tt9.util.Logger;
+
+public class HelpActivity extends AppCompatActivity {
+	@Override
+	protected void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		buildLayout();
+	}
+
+	@Override
+	public boolean onSupportNavigateUp() {
+		finish();
+		return true;
+	}
+
+	private void buildLayout() {
+		enableBackButton();
+		setContent();
+	}
+
+	private void enableBackButton() {
+		ActionBar actionBar = getSupportActionBar();
+		if (actionBar != null) {
+			actionBar.setDisplayShowHomeEnabled(true);
+			actionBar.setDisplayHomeAsUpEnabled(true);
+		}
+	}
+
+	private void setContent() {
+		WebView container = new WebView(this);
+
+		// On API > 30 the WebView does not load the entire String with .loadData(),
+		// so we need to do this weird shit.
+		// The "app:" prefix is mandatory, otherwise the anchor links do not work.
+		// Reference: https://developer.android.com/develop/ui/views/layout/webapps/webview
+		String html = getHelpHtml();
+		String encodedHtml = "app:" + Base64.encodeToString(html.getBytes(), Base64.NO_PADDING);
+		container.loadDataWithBaseURL(encodedHtml, html, "text/html", "UTF-8", null);
+
+		setContentView(container);
+	}
+
+	private String getHelpHtml() {
+		AssetManager assets = getAssets();
+		try {
+			InputStream stream = assets.open("help.html");
+			BufferedReader reader = new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8));
+			StringBuilder builder = new StringBuilder();
+			String line;
+			while ((line = reader.readLine()) != null) {
+				builder.append(line);
+			}
+			return builder.toString();
+		} catch (Exception e) {
+			Logger.e(getClass().getSimpleName(), "Failed opening the help.html file.");
+			return "";
+		}
+	}
+}

app/src/main/java/io/github/sspanak/tt9/preferences/screens/main/MainSettingsScreen.java

@@ -31,7 +31,6 @@ public class MainSettingsScreen extends BaseScreenFragment {
 	@Override
 	public void onCreate() {
 		createSettingsSection();
-		addHelpLink();
 		createAboutSection();
 		resetFontSize(false);
 	}
@@ -46,30 +45,6 @@ public class MainSettingsScreen extends BaseScreenFragment {
 	}
 
 
-	private void addHelpLink() {
-		try {
-			if (!releaseVersionRegex.matcher(BuildConfig.VERSION_NAME).find()) {
-				throw new Exception("VERSION_NAME does not match: \\d+.\\d+");
-			}
-
-			Preference helpSection = findPreference("help");
-			if (helpSection == null) {
-				throw new Exception("Could not find Help Preference");
-			}
-
-			String majorVersion = BuildConfig.VERSION_NAME.substring(0, BuildConfig.VERSION_NAME.indexOf('.'));
-			String versionedHelpUrl = getString(R.string.help_url).replace("blob/master", "blob/v" + majorVersion + ".0");
-
-			Intent intent = new Intent();
-			intent.setAction("android.intent.action.VIEW");
-			intent.setData(Uri.parse(versionedHelpUrl));
-			helpSection.setIntent(intent);
-		} catch (Exception e) {
-			Logger.w("MainSettingsScreen", "Could not set versioned help URL. Falling back to the default. " + e.getMessage());
-		}
-	}
-
-
 	private void createAboutSection() {
 		Preference donate = findPreference("donate_link");
 		if (donate != null) {

app/src/main/res/values/strings.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
 	<string translatable="false" name="dictionary_url">https://raw.githubusercontent.com/sspanak/tt9/%1$s/app/%2$s</string>
-	<string translatable="false" name="help_url">https://github.com/sspanak/tt9/blob/master/docs/user-manual.md</string>
 	<string name="app_name" translatable="false">Traditional T9</string>
 	<string name="app_name_short" translatable="false">TT9</string>
 	<string name="app_settings">TT9 Settings</string>

app/src/main/res/xml/prefs.xml

@@ -4,12 +4,13 @@
 	app:orderingFromXml="true">
 
 	<Preference
-		app:key="help"
-		app:summary="github.com/sspanak/tt9"
+		app:key="screen_help"
+		app:summary="English only"
 		app:title="@string/pref_help">
 		<intent
 			android:action="android.intent.action.VIEW"
-			android:data="@string/help_url" />
+			android:targetPackage="io.github.sspanak.tt9"
+			android:targetClass="io.github.sspanak.tt9.preferences.HelpActivity" />
 	</Preference>
 
 	<Preference