Refactor hotspot into a full page

- Deprecated WifiAPEnabler, and copied most of its logic into various
  controllers and WifiTetherSettings.
- Added tests

Fix: 37253404
Fix: 36181835

Test: make RunSettingsRoboTests
Change-Id: Iad994d61b694ad7f1113d045a3e7500eeaec178b

src/com/android/settings/widget/ValidatedEditTextPreference.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2017 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.settings.widget;
+
+import android.app.AlertDialog;
+import android.content.Context;
+import android.support.annotation.VisibleForTesting;
+import android.text.Editable;
+import android.text.InputType;
+import android.text.TextWatcher;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.EditText;
+
+import com.android.settings.CustomEditTextPreference;
+
+/**
+ * {@code EditTextPreference} that supports input validation.
+ */
+public class ValidatedEditTextPreference extends CustomEditTextPreference {
+
+    public interface Validator {
+        boolean isTextValid(String value);
+    }
+
+    private final EditTextWatcher mTextWatcher = new EditTextWatcher();
+    private Validator mValidator;
+    private boolean mIsPassword;
+
+    public ValidatedEditTextPreference(Context context, AttributeSet attrs,
+            int defStyleAttr, int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+    }
+
+    public ValidatedEditTextPreference(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    public ValidatedEditTextPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public ValidatedEditTextPreference(Context context) {
+        super(context);
+    }
+
+    @Override
+    protected void onBindDialogView(View view) {
+        super.onBindDialogView(view);
+        if (mValidator != null) {
+            final EditText editText = view.findViewById(android.R.id.edit);
+            if (editText != null) {
+                editText.removeTextChangedListener(mTextWatcher);
+                if (mIsPassword) {
+                    editText.setInputType(
+                            InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);
+                    editText.setMaxLines(1);
+                }
+                editText.addTextChangedListener(mTextWatcher);
+            }
+        }
+    }
+
+    public void setIsPassword(boolean isPassword) {
+        mIsPassword = isPassword;
+    }
+
+    @VisibleForTesting(otherwise = VisibleForTesting.NONE)
+    public boolean isPassword() {
+        return mIsPassword;
+    }
+
+    public void setValidator(Validator validator) {
+        mValidator = validator;
+    }
+
+    private class EditTextWatcher implements TextWatcher {
+        @Override
+        public void onTextChanged(CharSequence s, int start, int before, int count) {
+        }
+
+        @Override
+        public void beforeTextChanged(CharSequence s, int start, int before, int count) {
+        }
+
+        @Override
+        public void afterTextChanged(Editable s) {
+            final EditText editText = getEditText();
+            if (mValidator != null && editText != null) {
+                final AlertDialog dialog = (AlertDialog) getDialog();
+                final boolean valid = mValidator.isTextValid(editText.getText().toString());
+                dialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(valid);
+            }
+        }
+    }
+
+}