Migrate PaymentSettings to DashboardFragment

- Move preference related logic to controllers.
- Add some test cases for controllers.

Test: manual
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.nfc
      make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.core
      atest SettingsGatewayTest UniquePreferenceTest
Change-Id: I061a194c170f63fab51974f26c24be43d67d6f6f

src/com/android/settings/nfc/NfcForegroundPreferenceController.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2018 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.nfc;
+
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.text.TextUtils;
+
+import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
+import com.android.settingslib.core.lifecycle.LifecycleObserver;
+import com.android.settingslib.core.lifecycle.events.OnStart;
+import com.android.settingslib.core.lifecycle.events.OnStop;
+
+import java.util.List;
+
+import androidx.preference.DropDownPreference;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceScreen;
+
+public class NfcForegroundPreferenceController extends BasePreferenceController implements
+        PaymentBackend.Callback, Preference.OnPreferenceChangeListener,
+        LifecycleObserver, OnStart, OnStop {
+
+    private DropDownPreference mPreference;
+    private PaymentBackend mPaymentBackend;
+
+    public NfcForegroundPreferenceController(Context context, String key) {
+        super(context, key);
+    }
+
+    public void setPaymentBackend(PaymentBackend backend) {
+        mPaymentBackend = backend;
+    }
+
+    @Override
+    public void onStart() {
+        if (mPaymentBackend != null) {
+            mPaymentBackend.registerCallback(this);
+        }
+    }
+
+    @Override
+    public void onStop() {
+        if (mPaymentBackend != null) {
+            mPaymentBackend.unregisterCallback(this);
+        }
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        final PackageManager pm = mContext.getPackageManager();
+        if (!pm.hasSystemFeature(PackageManager.FEATURE_NFC)) {
+            return DISABLED_UNSUPPORTED;
+        }
+        if (mPaymentBackend == null) {
+            return DISABLED_UNSUPPORTED;
+        }
+        final List<PaymentBackend.PaymentAppInfo> appInfos = mPaymentBackend.getPaymentAppInfos();
+        return (appInfos != null && !appInfos.isEmpty())
+                ? AVAILABLE
+                : DISABLED_UNSUPPORTED;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mPreference = (DropDownPreference) screen.findPreference(getPreferenceKey());
+        if (mPreference == null) {
+            return;
+        }
+
+        mPreference.setEntries(new CharSequence[] {
+                mContext.getText(R.string.nfc_payment_favor_open),
+                mContext.getText(R.string.nfc_payment_favor_default)
+        });
+        mPreference.setEntryValues(new CharSequence[] {"1", "0"});
+    }
+
+    @Override
+    public void onPaymentAppsChanged() {
+        updateState(mPreference);
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        if (preference instanceof DropDownPreference) {
+            ((DropDownPreference) preference).setValue(
+                    mPaymentBackend.isForegroundMode() ? "1" : "0");
+        }
+        super.updateState(preference);
+    }
+
+    @Override
+    public CharSequence getSummary() {
+        return mPreference.getEntry();
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        if (!(preference instanceof DropDownPreference)) {
+            return false;
+        }
+        final DropDownPreference pref = (DropDownPreference) preference;
+        final String newValueString = (String) newValue;
+        pref.setSummary(pref.getEntries()[pref.findIndexOfValue(newValueString)]);
+        mPaymentBackend.setForegroundMode(Integer.parseInt(newValueString) != 0);
+        return true;
+    }
+
+    @Override
+    public void updateNonIndexableKeys(List<String> keys) {
+        final String key = getPreferenceKey();
+        if (!TextUtils.isEmpty(key)) {
+            keys.add(key);
+        }
+    }
+}