Show an error message if the address is invalid.

app/build.gradle

@@ -23,6 +23,6 @@ android {
 }
 
 dependencies {
-    implementation 'androidx.appcompat:appcompat:1.0.2'
-	implementation 'androidx.lifecycle:lifecycle-extensions:2.1.0'
+    implementation 'androidx.appcompat:appcompat:1.1.0'
+	implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
 }

app/src/main/java/org/briarproject/interferometer/MainActivity.java

@@ -5,16 +5,20 @@ import android.view.View;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import org.briarproject.interferometer.MainViewModel.ConnectionState;
+import org.briarproject.interferometer.MainViewModel.StartResult;
 import org.briarproject.interferometer.MainViewModel.TestPhase;
 
 import androidx.appcompat.app.AppCompatActivity;
-import androidx.lifecycle.ViewModelProviders;
+import androidx.lifecycle.ViewModelProvider;
 
+import static android.widget.Toast.LENGTH_SHORT;
 import static org.briarproject.interferometer.MainViewModel.ConnectionState.DISCONNECTED;
 import static org.briarproject.interferometer.MainViewModel.ConnectionState.DOWNLOADING;
 import static org.briarproject.interferometer.MainViewModel.ConnectionState.UPLOADING;
+import static org.briarproject.interferometer.MainViewModel.StartResult.INVALID_ADDRESS;
 import static org.briarproject.interferometer.MainViewModel.TestPhase.READY;
 
 public class MainActivity extends AppCompatActivity {
@@ -30,7 +34,7 @@ public class MainActivity extends AppCompatActivity {
 	protected void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 		setContentView(R.layout.activity_main);
-		viewModel = ViewModelProviders.of(this).get(MainViewModel.class);
+		viewModel = new ViewModelProvider(this).get(MainViewModel.class);
 		serverAddressEditText = findViewById(R.id.server_address_edit_text);
 		throughputTextView = findViewById(R.id.throughput_text_view);
 
@@ -66,7 +70,10 @@ public class MainActivity extends AppCompatActivity {
 	public void onTestClick(View view) {
 		TestPhase phase = viewModel.getTestPhase().getValue();
 		if (phase == null || phase == READY) {
-			viewModel.startTest(serverAddressEditText.getText().toString());
+			StartResult result = viewModel.startTest(serverAddressEditText.getText().toString());
+			if (result == INVALID_ADDRESS) {
+				Toast.makeText(this, R.string.server_address_error, LENGTH_SHORT).show();
+			}
 		} else {
 			viewModel.stopTest();
 		}

app/src/main/java/org/briarproject/interferometer/MainViewModel.java

@@ -23,6 +23,8 @@ import androidx.lifecycle.ViewModel;
 import static org.briarproject.interferometer.MainViewModel.ConnectionState.DISCONNECTED;
 import static org.briarproject.interferometer.MainViewModel.ConnectionState.DOWNLOADING;
 import static org.briarproject.interferometer.MainViewModel.ConnectionState.UPLOADING;
+import static org.briarproject.interferometer.MainViewModel.StartResult.INVALID_ADDRESS;
+import static org.briarproject.interferometer.MainViewModel.StartResult.STARTED;
 import static org.briarproject.interferometer.MainViewModel.TestPhase.DOWNLOAD;
 import static org.briarproject.interferometer.MainViewModel.TestPhase.READY;
 import static org.briarproject.interferometer.MainViewModel.TestPhase.UPLOAD;
@@ -33,6 +35,8 @@ public class MainViewModel extends ViewModel {
 
 	enum ConnectionState {DISCONNECTED, DOWNLOADING, UPLOADING}
 
+	enum StartResult {INVALID_ADDRESS, STARTED}
+
 	private static final byte CONNECTION_TYPE_UPLOAD = 0;
 	private static final byte CONNECTION_TYPE_DOWNLOAD = 1;
 	private static final int BUFFER_SIZE = 4096;
@@ -62,9 +66,9 @@ public class MainViewModel extends ViewModel {
 	}
 
 	@UiThread
-	void startTest(String serverAddress) {
+	StartResult startTest(String serverAddress) {
 		HostPort hostPort = parseServerAddress(serverAddress);
-		if (hostPort == null) return;
+		if (hostPort == null) return INVALID_ADDRESS;
 		task = executorService.submit(() -> {
 			try {
 				testPhase.postValue(DOWNLOAD);
@@ -86,6 +90,7 @@ public class MainViewModel extends ViewModel {
 				testPhase.postValue(READY);
 			}
 		});
+		return STARTED;
 	}
 
 	@UiThread

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

 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-	<color name="colorPrimary">#008577</color>
-	<color name="colorPrimaryDark">#00574B</color>
-	<color name="colorAccent">#D81B60</color>
+	<color name="colorPrimary">#007766</color>
+	<color name="colorPrimaryDark">#004433</color>
+	<color name="colorAccent">#00AA99</color>
 </resources>

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

@@ -2,6 +2,7 @@
 	<string name="app_name">Interferometer</string>
 
 	<string name="server_address">Server address</string>
+	<string name="server_address_error">Invalid address</string>
 
 	<string name="start_test">Start test</string>
 	<string name="stop_test">Stop test</string>