Upstreaming SelectFileDialog for Android

ui/android/java/src/org/chromium/ui/gfx/NativeWindow.java

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.gfx;
+
+import android.app.Activity;
+import android.content.ActivityNotFoundException;
+import android.content.ContentResolver;
+import android.content.Intent;
+import android.os.Bundle;
+import android.util.SparseArray;
+import android.widget.Toast;
+
+import java.io.Serializable;
+import java.util.HashMap;
+
+/**
+ * The window that has access to the main activity and is able to create and receive intents,
+ * and show error messages.
+ */
+public class NativeWindow {
+
+    // Constants used for intent request code bounding.
+    private static final int REQUEST_CODE_PREFIX = 1000;
+    private static final int REQUEST_CODE_RANGE_SIZE = 100;
+    // A string used as a key to store intent errors in a bundle
+    static final String WINDOW_CALLBACK_ERRORS = "window_callback_errors";
+
+    // Native pointer to the c++ WindowAndroid object.
+    private int mNativeWindowAndroid = 0;
+    private int mNextRequestCode = 0;
+    protected Activity mActivity;
+    private SparseArray<IntentCallback> mOutstandingIntents;
+    private HashMap<Integer, String> mIntentErrors;
+
+    /**
+     * An interface that intent callback objects have to implement.
+     */
+    public interface IntentCallback {
+        /**
+         * Handles the data returned by the requested intent.
+         * @param window A window reference.
+         * @param resultCode Result code of the requested intent.
+         * @param contentResolver An instance of ContentResolver class for accessing returned data.
+         * @param data The data returned by the intent.
+         */
+        public void onIntentCompleted(NativeWindow window, int resultCode,
+                ContentResolver contentResolver, Intent data);
+    }
+
+    /**
+     * Constructs a Window object, saves a reference to the main activity, and initializes the
+     * outstanding intent map. NativeWindowAndroid gets lazily loaded on getNativeWindow().
+     * @param activity The main application activity.
+     */
+    public NativeWindow(Activity activity) {
+        mActivity = activity;
+        mOutstandingIntents = new SparseArray<IntentCallback>();
+        mIntentErrors = new HashMap<Integer, String>();
+        mNativeWindowAndroid = 0;
+    }
+
+    /**
+     * Destroys the c++ WindowAndroid object if one has been created.
+     */
+    public void destroy() {
+        if (mNativeWindowAndroid != 0) {
+            nativeDestroy(mNativeWindowAndroid);
+            mNativeWindowAndroid = 0;
+        }
+    }
+
+    /**
+     * Shows an intent and returns the results to the callback object.
+     * @param intent The intent that needs to be showed.
+     * @param callback The object that will receive the results for the intent.
+     * @return Whether the intent was shown.
+     */
+    public boolean showIntent(Intent intent, IntentCallback callback) {
+        return showIntent(intent, callback, null);
+    }
+
+    /**
+     * Shows an intent and returns the results to the callback object.
+     * @param intent The intent that needs to be showed.
+     * @param callback The object that will receive the results for the intent.
+     * @param errorId The id of the error string to be show if activity is paused before intent
+     *                results.
+     * @return Whether the intent was shown.
+     */
+    public boolean showIntent(Intent intent, IntentCallback callback, int errorId) {
+        return showIntent(intent, callback, mActivity.getString(errorId));

[David Trainor- moved to gerrit, 2012/09/10 20:51:05]

What does getString do if you pass it an invalid resource id?  If it throws an
exception should we handle that?

[aurimas (slooooooooow), 2012/09/10 23:48:47]

Done.

+    }
+
+    /**
+     * Shows an intent and returns the results to the callback object.
+     * @param intent The intent that needs to be showed.
+     * @param callback The object that will receive the results for the intent.
+     * @param error The error string to be show if activity is paused before intent results.
+     * @return Whether the intent was shown.
+     */
+    public boolean showIntent(Intent intent, IntentCallback callback, String error) {
+        int requestCode = REQUEST_CODE_PREFIX + mNextRequestCode;
+        mNextRequestCode = (mNextRequestCode + 1) % REQUEST_CODE_RANGE_SIZE;
+
+        try {
+            mActivity.startActivityForResult(intent, requestCode);
+        } catch (ActivityNotFoundException e) {
+            return false;
+        }
+
+        mOutstandingIntents.put(requestCode, callback);
+        if (error != null) mIntentErrors.put(requestCode, error);
+
+        return true;
+    }
+
+    /**
+     * Saves the error messages that should be shown if any pending intents would return
+     * after the application has been put onPause.
+     * @param bundle The bundle to save the information in onPause
+     */
+    public void saveInstanceState(Bundle bundle) {
+        bundle.putSerializable(WINDOW_CALLBACK_ERRORS, mIntentErrors);
+    }
+
+    /**
+     * Restores the error messages that should be shown if any pending intents would return
+     * after the application has been put onPause.
+     * @param bundle The bundle to restore the information from onResume
+     */
+    public void restoreInstanceState(Bundle bundle) {
+        if (bundle == null) return;
+
+        Object errors = bundle.getSerializable(WINDOW_CALLBACK_ERRORS);
+        if (errors instanceof HashMap) {
+            @SuppressWarnings("unchecked")
+            HashMap<Integer, String> intentErrors = (HashMap<Integer, String>) errors;

[David Trainor- moved to gerrit, 2012/09/10 20:51:05]

Can get rid of intentErrors, just do mIntentErrors = (HashMap<Integer, String>)
errors;

[aurimas (slooooooooow), 2012/09/10 23:48:47]

I tried doing that, but then the @SuppressWarnings does not work. Not sure what
is up with that.

+            mIntentErrors = intentErrors;
+        }
+    }
+
+    /**
+     * Displays an error message with a provided error message string.
+     * @param error The error message string to be displayed.
+     */
+    public void showError(String error) {
+        Toast.makeText(mActivity, error, Toast.LENGTH_SHORT).show();

[David Trainor- moved to gerrit, 2012/09/10 20:51:05]

What if error is null?

[aurimas (slooooooooow), 2012/09/10 23:48:47]

Done.

+    }
+
+    /**
+     * Displays an error message with a provided error message string id.
+     * @param errorId The string id of the error message string to be displayed.
+     */
+    public void showError(int errorId) {
+        showError(mActivity.getString(errorId));

[David Trainor- moved to gerrit, 2012/09/10 20:51:05]

getString check again?  Not sure what happens if it isn't a valid resource id.

[aurimas (slooooooooow), 2012/09/10 23:48:47]

Done.

+    }
+
+    /**
+     * Displays an error message for a nonexistent callback.
+     * @param error The error message string to be displayed.
+     */
+    protected void showCallbackNonExistent(String error) {

[David Trainor- moved to gerrit, 2012/09/10 20:51:05]

I know I'm responsible for this name, but put Error at the end or something. 
Sorry!

[aurimas (slooooooooow), 2012/09/10 23:48:47]

Done.

+        showError(error);
+    }
+
+    /**
+     * @return The main application activity.
+     */
+    public Activity getActivity() {
+        return mActivity;
+    }
+
+    /**
+     * Responds to the intent result if the intent was created by the native window.
+     * @param requestCode Request code of the requested intent.
+     * @param resultCode Result code of the requested intent.
+     * @param data The data returned by the intent.
+     * @return Boolean value of whether the intent was started by the native window.
+     */
+    public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
+        IntentCallback callback = mOutstandingIntents.get(requestCode);

[David Trainor- moved to gerrit, 2012/09/10 20:51:05]

Remove the id from the mIntentErrors here... if we successfully process the
intent then we will leave the id in the map forever.

[aurimas (slooooooooow), 2012/09/10 23:48:47]

Done.

+        mOutstandingIntents.delete(requestCode);
+
+        if (callback != null) {
+            callback.onIntentCompleted(this, resultCode,
+                    mActivity.getContentResolver(), data);
+            return true;
+        } else {
+            String errorMessage = mIntentErrors.remove(requestCode);
+            if (errorMessage != null) {
+                showCallbackNonExistent(errorMessage);
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns a pointer to the c++ AndroidWindow object and calls the initializer if
+     * the object has not been previously initialized.
+     * @return A pointer to the c++ AndroidWindow.
+     */
+    public int getNativePointer() {
+        if (mNativeWindowAndroid == 0) {
+            mNativeWindowAndroid = nativeInit();
+        }
+        return mNativeWindowAndroid;
+    }
+
+    private native int nativeInit();
+    private native void nativeDestroy(int nativeWindowAndroid);
+
+}