Settings Fragment Migration (Build pass app)

This patch focused on fixing compile errors and some runtime errors.

Test: We can't test it now. But we will have an integration test later.
Bug: 110259478
Change-Id: I16c471ddcd0fa1460c665b7f74d86fcace5ee67b

src/com/android/settings/print/PrintServiceSettingsFragment.java

@@ -28,7 +28,6 @@ import android.graphics.drawable.ColorDrawable;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.print.PrintManager;
-import android.print.PrintServicesLoader;
 import android.print.PrinterDiscoverySession;
 import android.print.PrinterDiscoverySession.OnPrintersChangeListener;
 import android.print.PrinterId;

src/com/android/settings/print/PrintServicesLoader.java

@@ -0,0 +1,126 @@
+/*
+ * 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.print;
+
+import android.annotation.NonNull;
+import android.content.Context;
+import android.os.Handler;
+import android.os.Message;
+import android.print.PrintManager;
+import android.printservice.PrintServiceInfo;
+
+import com.android.internal.util.Preconditions;
+
+import java.util.List;
+
+import androidx.loader.content.Loader;
+
+/**
+ * Loader for the list of print services. Can be parametrized to select a subset.
+ *
+ */
+public class PrintServicesLoader extends Loader<List<PrintServiceInfo>> {
+    /** What type of services to load. */
+    private final int mSelectionFlags;
+
+    /** The print manager to be used by this object */
+    private final @NonNull PrintManager mPrintManager;
+
+    /** Handler to sequentialize the delivery of the results to the main thread */
+    private final @NonNull Handler mHandler;
+
+    /** Listens for updates to the data from the platform */
+    private PrintManager.PrintServicesChangeListener mListener;
+
+    /**
+     * Create a new PrintServicesLoader.
+     *
+     * @param printManager   The print manager supplying the data
+     * @param context        Context of the using object
+     * @param selectionFlags What type of services to load.
+     */
+    public PrintServicesLoader(@NonNull PrintManager printManager, @NonNull Context context,
+            int selectionFlags) {
+        super(Preconditions.checkNotNull(context));
+        mHandler = new MyHandler();
+        mPrintManager = Preconditions.checkNotNull(printManager);
+        mSelectionFlags = Preconditions.checkFlagsArgument(selectionFlags,
+                PrintManager.ALL_SERVICES);
+    }
+
+    @Override
+    protected void onForceLoad() {
+        queueNewResult();
+    }
+
+    /**
+     * Read the print services and queue it to be delivered on the main thread.
+     */
+    private void queueNewResult() {
+        Message m = mHandler.obtainMessage(0);
+        m.obj = mPrintManager.getPrintServices(mSelectionFlags);
+        mHandler.sendMessage(m);
+    }
+
+    @Override
+    protected void onStartLoading() {
+        mListener = new PrintManager.PrintServicesChangeListener() {
+            @Override public void onPrintServicesChanged() {
+                queueNewResult();
+            }
+        };
+
+        mPrintManager.addPrintServicesChangeListener(mListener, null);
+
+        // Immediately deliver a result
+        deliverResult(mPrintManager.getPrintServices(mSelectionFlags));
+    }
+
+    @Override
+    protected void onStopLoading() {
+        if (mListener != null) {
+            mPrintManager.removePrintServicesChangeListener(mListener);
+            mListener = null;
+        }
+
+        mHandler.removeMessages(0);
+    }
+
+    @Override
+    protected void onReset() {
+        onStopLoading();
+    }
+
+    /**
+     * Handler to sequentialize all the updates to the main thread.
+     */
+    private class MyHandler extends Handler {
+        /**
+         * Create a new handler on the main thread.
+         */
+        public MyHandler() {
+            super(getContext().getMainLooper());
+        }
+
+        @Override
+        public void handleMessage(Message msg) {
+            if (isStarted()) {
+                deliverResult((List<PrintServiceInfo>) msg.obj);
+            }
+        }
+    }
+}

src/com/android/settings/print/PrintSettingsFragment.java

@@ -32,7 +32,6 @@ import android.print.PrintJobId;
 import android.print.PrintJobInfo;
 import android.print.PrintManager;
 import android.print.PrintManager.PrintJobStateChangeListener;
-import android.print.PrintServicesLoader;
 import android.printservice.PrintServiceInfo;
 import android.provider.SearchIndexableResource;
 import android.provider.Settings;