Add SonarDiagnosticActivity to android

Summary:
Open the screen by running adb shell
am start -n com.facebook.samples.litho/com.facebook.sonar.android.diagnostics.SonarDiagnosticActivity

Reviewed By: danielbuechele

Differential Revision: D9150556

fbshipit-source-id: 534583cfa5e90af6fd0d2a50572e3763b8888da2

android/sample/AndroidManifest.xml

@@ -24,7 +24,8 @@
         <category android:name="android.intent.category.LAUNCHER"/>
       </intent-filter>
     </activity>
+    <activity android:name="com.facebook.sonar.android.diagnostics.SonarDiagnosticActivity"
+        android:exported="true"/>
   </application>
 
-
 </manifest>

android/src/main/java/com/facebook/sonar/android/diagnostics/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application>
+        <activity android:name="com.facebook.sonar.android.diagnostics.SonarDiagnosticActivity"
+                 android:exported="true" />
+    </application>
+</manifest>

android/src/main/java/com/facebook/sonar/android/diagnostics/SonarDiagnosticActivity.java

@@ -0,0 +1,64 @@
+package com.facebook.sonar.android.diagnostics;
+
+import android.app.Activity;
+import android.content.Context;
+import android.os.Bundle;
+import android.widget.Toast;
+import com.facebook.sonar.android.AndroidSonarClient;
+import com.facebook.sonar.core.SonarClient;
+import com.facebook.sonar.core.SonarStateUpdateListener;
+import android.widget.LinearLayout;
+import android.view.View;
+import android.widget.TextView;
+import android.widget.ScrollView;
+
+public class SonarDiagnosticActivity extends Activity implements SonarStateUpdateListener {
+
+  private TextView textView;
+  private ScrollView scrollView;
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+
+    LinearLayout root = new LinearLayout(this);
+
+    textView = new TextView(this);
+    scrollView = new ScrollView(this);
+    scrollView.addView(textView);
+    root.addView(scrollView);
+
+    setContentView(root);
+  }
+
+  protected void onStart() {
+    super.onStart();
+    SonarClient client = AndroidSonarClient.getInstance(this);
+    client.subscribeForUpdates(this);
+    textView.setText(client.getState());
+  }
+
+  protected void onResume() {
+    super.onResume();
+    scrollView.fullScroll(View.FOCUS_DOWN);
+  }
+
+@Override
+  public void onUpdate() {
+    final Context context = this;
+    final String state = AndroidSonarClient.getInstance(context).getState();
+    runOnUiThread(new Runnable() {
+      @Override
+      public void run() {
+        textView.setText(state);
+        scrollView.fullScroll(View.FOCUS_DOWN);
+      }
+    });
+  }
+
+  protected void onStop() {
+    super.onStop();
+    SonarClient client = AndroidSonarClient.getInstance(this);
+    client.unsubscribe();
+  }
+}