added strike through feature

.gitignore

@@ -12,4 +12,4 @@
 /app/build
 /captures
 .externalNativeBuild
-.cxx
+.cxx

app/build.gradle

@@ -7,9 +7,9 @@ android {
     defaultConfig {
         applicationId "de.docweirdo.spongemock"
         minSdkVersion 23
-        targetSdkVersion 29
-        versionCode 3
-        versionName "1.2"
+        targetSdkVersion 30
+        versionCode 4
+        versionName "1.3"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }

app/src/main/AndroidManifest.xml

@@ -27,6 +27,15 @@
                 <data android:mimeType="text/plain" />
             </intent-filter>
         </activity>
+        <activity
+            android:name=".StrikeThrough"
+            android:label="@string/process_text_action_name_strike_through">
+            <intent-filter>
+                <action android:name="android.intent.action.PROCESS_TEXT" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/plain" />
+            </intent-filter>
+        </activity>
     </application>
 
 </manifest>

app/src/main/java/de/docweirdo/spongemock/StrikeThrough.java

@@ -0,0 +1,82 @@
+package de.docweirdo.spongemock;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.content.ClipData;
+import android.content.ClipboardManager;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.widget.Toast;
+
+
+public class StrikeThrough extends AppCompatActivity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        CharSequence text = getIntent()
+                .getCharSequenceExtra(Intent.EXTRA_PROCESS_TEXT);
+
+        boolean readonly = getIntent()
+                .getBooleanExtra(Intent.EXTRA_PROCESS_TEXT_READONLY, false);
+
+        assert text != null;
+
+        String replacementText = strikeThrough(text.toString());
+
+        if (readonly){
+
+            ClipboardManager cm = (ClipboardManager) getSystemService(Context.CLIPBOARD_SERVICE);
+            ClipData cd = ClipData.newPlainText("struck through text", replacementText);
+            cm.setPrimaryClip(cd);
+
+            Context context = getApplicationContext();
+            CharSequence msg = "Struck through text copied to clipboard";
+            int duration = Toast.LENGTH_SHORT;
+            Toast toast = Toast.makeText(context, msg, duration);
+            toast.show();
+            finish();
+
+        } else {
+            Intent intent = new Intent();
+            intent.putExtra(Intent.EXTRA_PROCESS_TEXT, replacementText);
+            setResult(RESULT_OK, intent);
+            finish();
+        }
+    }
+
+    protected String strikeThrough(String text){
+
+        char cp = '\u0336';
+
+        text = insertPeriodically(text, cp, 1);
+
+        return text;
+    }
+
+    public static String insertPeriodically(
+    String text, char character, int period)
+    {
+        StringBuilder builder = new StringBuilder(
+            text.length() * (text.length()/period)+1);
+
+        int index = 0;
+        String prefix = "";
+        while (index < text.length())
+        {
+            // Don't put the insert in the very first iteration.
+            // This is easier than appending it *after* each substring
+            builder.append(prefix);
+            prefix = "" + character;
+            builder.append(text.substring(index, 
+                Math.min(index + period, text.length())));
+            index += period;
+        }
+
+        builder.append(prefix);
+
+        return builder.toString();
+    }
+}

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

@@ -2,4 +2,5 @@
     <string name="app_name">Morbus Mock</string>
     <string name="process_text_action_name_mock">Mock</string>
     <string name="process_text_action_name_special">Specialize</string>
+    <string name="process_text_action_name_strike_through">Strike</string>
 </resources>