Merge pull request #263 from stratomda/feature/recent_masters

Adds capability to remember recent hosts.

android_10/res/layout/master_chooser.xml

@@ -18,7 +18,7 @@
             android:text="@string/uri_text"
             android:textSize="18dp"/>
 
-        <EditText
+        <AutoCompleteTextView
             android:id="@+id/master_chooser_uri"
             android:layout_width="0dp"
             android:layout_height="wrap_content"
@@ -27,7 +27,7 @@
             android:singleLine="true">
 
             <requestFocus/>
-        </EditText>
+        </AutoCompleteTextView>
     </LinearLayout>
 
     <LinearLayout

android_10/src/org/ros/android/MasterChooser.java

@@ -30,9 +30,9 @@ import android.os.Bundle;
 import android.text.Editable;
 import android.text.TextWatcher;
 import android.view.View;
+import android.widget.AutoCompleteTextView;
 import android.widget.Button;
 import android.widget.CheckBox;
-import android.widget.EditText;
 import android.widget.Toast;
 import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
@@ -54,6 +54,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
+import java.util.Set;
 import java.util.regex.Pattern;
 
 /**
@@ -99,8 +100,23 @@ public class MasterChooser extends Activity {
    */
   private static final int DEFAULT_PORT = 11311;
 
+  /**
+   *The preferences key used for obtaining the number of recent Master URIs.
+   */
+  private static final String RECENT_COUNT_KEY_NAME = "RECENT_MASTER_URI_COUNT";
+
+  /**
+   * The preference key prefix used for obtaining the recent Master URIs.
+   */
+  private static final String RECENT_PREFIX_KEY_NAME = "RECENT_MASTER_URI_";
+
+  /**
+   * Number of recent Master URIs to store into preferences.
+   */
+  private static final int RECENT_MASTER_HISTORY_COUNT = 5;
+
   private String selectedInterface;
-  private EditText uriText;
+  private AutoCompleteTextView uriText;
   private Button connectButton;
   private LinearLayout connectionLayout;
 
@@ -132,8 +148,14 @@ public class MasterChooser extends Activity {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.master_chooser);
     final Pattern uriPattern = RosURIPattern.URI;
-    uriText = (EditText) findViewById(R.id.master_chooser_uri);
+    uriText = (AutoCompleteTextView) findViewById(R.id.master_chooser_uri);
     connectButton = (Button) findViewById(R.id.master_chooser_ok);
+    uriText.setThreshold(RosURIPattern.HTTP_PROTOCOL_LENGTH);
+
+    ArrayAdapter<String> uriAdapter = new ArrayAdapter<>
+            (this,android.R.layout.select_dialog_item,getRecentMasterURIs());
+    uriText.setAdapter(uriAdapter);
+
     uriText.addTextChangedListener(new TextWatcher() {
       @Override
       public void onTextChanged(CharSequence s, int start, int before, int count) {
@@ -274,10 +296,9 @@ public class MasterChooser extends Activity {
           }
         });
         if (result) {
+          //Update Recent Master URI
+          addRecentMasterURI(uri);
           // If the displayed URI is valid then pack that into the intent.
-          SharedPreferences.Editor editor = getPreferences(MODE_PRIVATE).edit();
-          editor.putString(PREFS_KEY_NAME, uri);
-          editor.commit();
           // Package the intent to be consumed by the calling activity.
           Intent intent = createNewMasterIntent(false, true);
           setResult(RESULT_OK, intent);
@@ -363,6 +384,52 @@ public class MasterChooser extends Activity {
     return (list.size() > 0);
   }
 
+  /**
+   * Adds the given URI to the list of recent Master URIs stored in shared preferences.
+   * This implementation does not use
+   * {@link android.content.SharedPreferences.Editor#putStringSet(String, Set)}
+   * since it is not available in API 10.
+   * @param uri Master URI string to store.
+   */
+  private void addRecentMasterURI(String uri) {
+    List<String> recentURIs = getRecentMasterURIs();
+    if (!recentURIs.contains(uri)) {
+      recentURIs.add(0, uri);
+      if (recentURIs.size() > RECENT_MASTER_HISTORY_COUNT)
+        recentURIs = recentURIs.subList(0, RECENT_MASTER_HISTORY_COUNT);
+    }
+
+    SharedPreferences.Editor editor = getPreferences(MODE_PRIVATE).edit();
+    editor.putString(PREFS_KEY_NAME, uri);
+    for (int i = 0; i < recentURIs.size(); i++) {
+      editor.putString(RECENT_PREFIX_KEY_NAME + String.valueOf(i), recentURIs.get(i));
+    }
+
+    editor.putInt(RECENT_COUNT_KEY_NAME, recentURIs.size());
+    editor.apply();
+  }
+
+  /**
+   * Gets a list of recent Master URIs from shared preferences. This implementation does not use
+   * {@link android.content.SharedPreferences.Editor#putStringSet(String, Set)}
+   * since it is not available in API 10.
+   * @return List of recent Master URI strings
+   */
+  private List<String> getRecentMasterURIs() {
+    List<String> recentURIs;
+    SharedPreferences prefs = getPreferences(MODE_PRIVATE);
+    int numRecent = prefs.getInt(RECENT_COUNT_KEY_NAME, 0);
+    recentURIs = new ArrayList<>(numRecent);
+    for (int i = 0; i < numRecent; i++) {
+      String uri = prefs.getString(RECENT_PREFIX_KEY_NAME + String.valueOf(i), "");
+      if (!uri.isEmpty()) {
+        recentURIs.add(uri);
+      }
+    }
+
+    return recentURIs;
+  }
+
   /**
    * Regular expressions used with ROS URIs.
    *
@@ -426,6 +493,8 @@ public class MasterChooser extends Activity {
 
     private static final String HTTP_PROTOCOL = "(?i:http):\\/\\/";
 
+    public static final int HTTP_PROTOCOL_LENGTH = ("http://").length();
+
     private static final String PORT_NUMBER = "\\:\\d{1,5}\\/?";
 
     /**