Don't update the same indication

Update the same indication would make TalkBack
announce same messages repeatedly. Only update
the indication if it changes.

Test: Manual
Test: atest SystemUITests:KeyguardIndicationTextViewTest
Bug: 150737351
Change-Id: Ifc7ae496ee9324fe5fb52d7694daf7839166bbd5

packages/SystemUI/src/com/android/systemui/statusbar/phone/KeyguardIndicationTextView.java

@@ -27,6 +27,8 @@ import android.widget.TextView;
  */
 public class KeyguardIndicationTextView extends TextView {
 
+    private CharSequence mText = "";
+
     public KeyguardIndicationTextView(Context context) {
         super(context);
     }
@@ -53,10 +55,12 @@ public class KeyguardIndicationTextView extends TextView {
 
         // TODO: Animation, make sure that we will show one indication long enough.
         if (TextUtils.isEmpty(text)) {
+            mText = "";
             setVisibility(View.INVISIBLE);
-        } else {
+        } else if (!TextUtils.equals(text, mText)) {
+            mText = text;
             setVisibility(View.VISIBLE);
-            setText(text);
+            setText(mText);
         }
     }
 

packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/KeyguardIndicationTextViewTest.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.statusbar.phone;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.testing.AndroidTestingRunner;
+import android.testing.TestableLooper;
+import android.view.View;
+
+import androidx.test.filters.SmallTest;
+
+import com.android.systemui.SysuiTestCase;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@SmallTest
+@RunWith(AndroidTestingRunner.class)
+@TestableLooper.RunWithLooper
+public class KeyguardIndicationTextViewTest extends SysuiTestCase {
+
+    private KeyguardIndicationTextView mKeyguardIndicationTextView;
+
+    @Before
+    public void setup() {
+        mKeyguardIndicationTextView = new KeyguardIndicationTextView(mContext);
+    }
+
+    @Test
+    public void switchIndication_null_hideIndication() {
+        mKeyguardIndicationTextView.switchIndication(null /* text */);
+
+        assertThat(mKeyguardIndicationTextView.getVisibility()).isEqualTo(View.INVISIBLE);
+        assertThat(mKeyguardIndicationTextView.getText()).isEqualTo("");
+    }
+
+    @Test
+    public void switchIndication_emptyText_hideIndication() {
+        mKeyguardIndicationTextView.switchIndication("" /* text */);
+
+        assertThat(mKeyguardIndicationTextView.getVisibility()).isEqualTo(View.INVISIBLE);
+        assertThat(mKeyguardIndicationTextView.getText()).isEqualTo("");
+    }
+
+    @Test
+    public void switchIndication_newText_updateProperly() {
+        mKeyguardIndicationTextView.switchIndication("test_indication" /* text */);
+
+        assertThat(mKeyguardIndicationTextView.getVisibility()).isEqualTo(View.VISIBLE);
+        assertThat(mKeyguardIndicationTextView.getText()).isEqualTo("test_indication");
+    }
+}