Add button to toggle passphrase visibility

closes #3776
// FREEBIE

res/layout/prompt_passphrase_activity.xml

@@ -32,7 +32,40 @@
                       android:layout_marginRight="50dp"
                       android:singleLine="true"
                       android:paddingLeft="10dp"
-                      android:paddingRight="10dp"/>
+                      android:paddingRight="40dp"/>
+
+            <org.thoughtcrime.securesms.components.AnimatingToggle
+                    android:id="@+id/button_toggle"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_alignRight="@+id/passphrase_edit"
+                    android:layout_centerVertical="true"
+                    android:layout_gravity="center"
+                    android:gravity="center">
+
+                <ImageButton android:id="@+id/passphrase_visibility"
+                             android:src="?ic_visibility"
+                             android:background="@drawable/touch_highlight_background"
+                             android:layout_width="wrap_content"
+                             android:layout_height="wrap_content"
+                             android:paddingLeft="8dp"
+                             android:paddingRight="8dp"
+                             android:paddingTop="3dp"
+                             android:paddingBottom="3dp"
+                             android:layout_centerVertical="true" />
+
+                <ImageButton android:id="@+id/passphrase_visibility_off"
+                             android:src="?ic_visibility_off"
+                             android:background="@drawable/touch_highlight_background"
+                             android:layout_width="wrap_content"
+                             android:layout_height="wrap_content"
+                             android:paddingLeft="8dp"
+                             android:paddingRight="8dp"
+                             android:paddingTop="3dp"
+                             android:paddingBottom="3dp"
+                             android:layout_centerVertical="true" />
+
+            </org.thoughtcrime.securesms.components.AnimatingToggle>
 
             <ImageButton android:id="@+id/ok_button"
                          android:src="?ic_arrow_forward"

res/values/attrs.xml

@@ -23,6 +23,8 @@
 
     <attr name="centered_app_title_color" format="reference|color" />
     <attr name="ic_arrow_forward" format="reference" />
+    <attr name="ic_visibility" format="reference" />
+    <attr name="ic_visibility_off" format="reference" />
 
     <attr name="conversation_background" format="reference|color"/>
     <attr name="conversation_editor_background" format="reference|color"/>

res/values/themes.xml

@@ -46,6 +46,8 @@
         <item name="centered_app_title_color">#55000000</item>
         <item name="ic_arrow_forward">@drawable/ic_arrow_forward_light</item>
         <item name="lockscreen_watermark">@drawable/lockscreen_watermark_light</item>
+        <item name="ic_visibility">@drawable/ic_visibility_grey600_24dp</item>
+        <item name="ic_visibility_off">@drawable/ic_visibility_off_grey600_24dp</item>
     </style>
 
     <style name="TextSecure.DarkIntroTheme" parent="@style/Theme.AppCompat">
@@ -57,6 +59,8 @@
         <item name="ic_arrow_forward">@drawable/ic_arrow_forward_dark</item>
         <item name="lockscreen_watermark">@drawable/lockscreen_watermark_dark</item>
         <item name="android:windowBackground">@color/black</item>
+        <item name="ic_visibility">@drawable/ic_visibility_white_24dp</item>
+        <item name="ic_visibility_off">@drawable/ic_visibility_off_white_24dp</item>
     </style>
 
     <style name="PopupAnimation" parent="@android:style/Animation">

src/org/thoughtcrime/securesms/PassphrasePromptActivity.java

@@ -20,6 +20,7 @@ import android.content.Intent;
 import android.os.Bundle;
 import android.support.v7.app.ActionBar;
 import android.text.Editable;
+import android.text.InputType;
 import android.text.SpannableString;
 import android.text.Spanned;
 import android.text.style.RelativeSizeSpan;
@@ -36,6 +37,7 @@ import android.widget.ImageButton;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import org.thoughtcrime.securesms.components.AnimatingToggle;
 import org.thoughtcrime.securesms.crypto.InvalidPassphraseException;
 import org.thoughtcrime.securesms.crypto.MasterSecretUtil;
 import org.thoughtcrime.securesms.util.DynamicIntroTheme;
@@ -53,6 +55,9 @@ public class PassphrasePromptActivity extends PassphraseActivity {
   private DynamicLanguage   dynamicLanguage = new DynamicLanguage();
 
   private EditText        passphraseText;
+  private ImageButton     showButton;
+  private ImageButton     hideButton;
+  private AnimatingToggle visibilityToggle;
 
   @Override
   public void onCreate(Bundle savedInstanceState) {
@@ -116,11 +121,27 @@ public class PassphrasePromptActivity extends PassphraseActivity {
     }
   }
 
+  private void setPassphraseVisibility(boolean visibility) {
+    int cursorPosition = passphraseText.getSelectionStart();
+    if (visibility) {
+      passphraseText.setInputType(InputType.TYPE_CLASS_TEXT |
+                                  InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD);
+    } else {
+      passphraseText.setInputType(InputType.TYPE_CLASS_TEXT |
+                                  InputType.TYPE_TEXT_VARIATION_PASSWORD);
+    }
+    passphraseText.setSelection(cursorPosition);
+  }
+
   private void initializeResources() {
     getSupportActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
     getSupportActionBar().setCustomView(R.layout.centered_app_title);
 
     ImageButton okButton = (ImageButton) findViewById(R.id.ok_button);
+
+    showButton       = (ImageButton)     findViewById(R.id.passphrase_visibility);
+    hideButton       = (ImageButton)     findViewById(R.id.passphrase_visibility_off);
+    visibilityToggle = (AnimatingToggle) findViewById(R.id.button_toggle);
     passphraseText   = (EditText)        findViewById(R.id.passphrase_edit);
     SpannableString hint = new SpannableString("  " + getString(R.string.PassphrasePromptActivity_enter_passphrase));
     hint.setSpan(new RelativeSizeSpan(0.9f), 0, hint.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE);
@@ -128,6 +149,8 @@ public class PassphrasePromptActivity extends PassphraseActivity {
 
     passphraseText.setHint(hint);
     okButton.setOnClickListener(new OkButtonClickListener());
+    showButton.setOnClickListener(new ShowButtonOnClickListener());
+    hideButton.setOnClickListener(new HideButtonOnClickListener());
     passphraseText.setOnEditorActionListener(new PassphraseActionListener());
     passphraseText.setImeActionLabel(getString(R.string.prompt_passphrase_activity__unlock),
                                      EditorInfo.IME_ACTION_DONE);
@@ -159,6 +182,22 @@ public class PassphrasePromptActivity extends PassphraseActivity {
     }
   }
 
+  private class ShowButtonOnClickListener implements OnClickListener {
+    @Override
+    public void onClick(View v) {
+      visibilityToggle.display(hideButton);
+      setPassphraseVisibility(true);
+    }
+  }
+
+  private class HideButtonOnClickListener implements OnClickListener {
+    @Override
+    public void onClick(View v) {
+      visibilityToggle.display(showButton);
+      setPassphraseVisibility(false);
+    }
+  }
+
   @Override
   protected void cleanup() {
     this.passphraseText.setText("");