我正在尝试将Google Analytics实施到我的Android应用中。我按照这里的教程：Add Analytics to Your Android App
我复制了AnalyticsApplication子类的源代码并将其粘贴到新的java类中。我将包名更改为我自己的，并在第41行设置我的跟踪ID的名称作为newTracker方法的参数。然后，在我的MainActivityactivity中，我在第33和36行添加了一个日志标记和一个Tracker变量。在第161-173行中，我重写了onResume方法并设置了一些日志信息和数据以发送到Google Analytics。
以下是AnalyticsApplication类：
/*
* Copyright Google Inc. All Rights Reserved.
*
* 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.lawrence.daniel.usbidentifier;
import android.app.Application;
import com.google.android.gms.analytics.GoogleAnalytics;
import com.google.android.gms.analytics.Logger;
import com.google.android.gms.analytics.Tracker;
import com.lawrence.daniel.usbidentifier.R;
/**
* This is a subclass of {@link Application} used to provide shared objects for this app, such as
* the {@link Tracker}.
*/
public class AnalyticsApplication extends Application {
private Tracker mTracker;
/**
* Gets the default {@link Tracker} for this {@link Application}.
* @return tracker
*/
synchronized public Tracker getDefaultTracker() {
if (mTracker == null) {
GoogleAnalytics analytics = GoogleAnalytics.getInstance(this);
// To enable debug logging use: adb shell setprop log.tag.GAv4 DEBUG
mTracker = analytics.newTracker("UA-73160447-1");
}
return mTracker;
}
}
这是MainActivity活动：
package com.lawrence.daniel.usbidentifier;
import android.app.ListActivity;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.hardware.usb.UsbAccessory;
import android.hardware.usb.UsbManager;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import com.google.android.gms.analytics.HitBuilders;
import com.google.android.gms.analytics.Tracker;
/**
* @author Daniel Lawrence
* <p>
* The USB Identifier identifies a USB device and returns
* its Description, Manufacturer, Model, Serial Number,
* Version, and Hash Code.
* <p>
* Version 1.0
*/
public class MainActivity extends ListActivity {
// A tag for debugging.
private static final String TAG = "MainActivity";
// A variable to track app events.
private Tracker mTracker;
/*
* Derived from Android Documentation.
* API Guides --> Connectivity --> Accessory
*/
// Declare an array for storing accessory information values later on.
static final String[] ACCESSORY_INFO = new String[5];
private static final String ACTION_USB_PERMISSION =
"com.lawrence.daniel.USB_PERMISSION";
/*
The mUsbReceiver broadcast receiver listens for an Android accessory to be
plugged into the phone.
V 1.1
*/
private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
/**
* If a connection between a USB device and an Android device is made,
* a dialog box displays, asking the user to accept or reject the connection.
* If the connection is accepted, the USB device will communicate information
* to the Android device.
*
* @param context The application context.
* @param intent
*
* Version 1.0
*/
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
/*
If a connection is made, the user can accept or reject the connection.
*/
if (ACTION_USB_PERMISSION.equals(action)) {
synchronized (this) {
UsbAccessory accessory = intent.getParcelableExtra(UsbManager.EXTRA_ACCESSORY);
// If the connection is accepted, both devices will communicate.
if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
if (accessory != null) {
// create method to set up communication
}
}
// Otherwise, a Toast is made.
else {
Toast.makeText(MainActivity.this,
"permission denied for accessory",
Toast.LENGTH_SHORT).show();
}
}
}
}
};
// Declare a global UsbManager variable.
UsbManager mUsbManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create a new instance of the AnalyticsApplication class.
/**********************************************************
Shows ClassCastException in LogCat.
**********************************************************/
AnalyticsApplication application = (AnalyticsApplication) getApplication();
mTracker = application.getDefaultTracker();
// Initialize the UsbManager.
mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
// Create a list of accessories attached (current implementation only allows one device).
UsbAccessory[] accessoryList = mUsbManager.getAccessoryList();
// Instantiate a Pending Intent object to get the broadcast made when a device is connected.
PendingIntent mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
// Instantiate an IntentFilter object.
IntentFilter permissionFilter = new IntentFilter(ACTION_USB_PERMISSION);
try {
/*
V 1.3
*/
// Register the Broadcast Receiver named mUsbReceiver with the proper IntentFilters.
registerReceiver(mUsbReceiver, permissionFilter);
// Displays a dialog for the user to accept or reject the connection.
mUsbManager.requestPermission(accessoryList[0], mPermissionIntent);
// Call the openAccessory method to open communication with the accessory.
mUsbManager.openAccessory(accessoryList[0]);
// Fill the ACCESSORY_INFO array with the accessory's info so it can populate the ListView.
ACCESSORY_INFO[0] = accessoryList[0].getDescription();
ACCESSORY_INFO[1] = accessoryList[0].getManufacturer();
ACCESSORY_INFO[2] = accessoryList[0].getModel();
ACCESSORY_INFO[3] = accessoryList[0].getSerial();
ACCESSORY_INFO[4] = accessoryList[0].getVersion();
// Populate the ListView with the accessory's info.
setListAdapter(new ArrayAdapter<>(MainActivity.this,
android.R.layout.simple_list_item_1, ACCESSORY_INFO));
getListView().setChoiceMode(ListView.CHOICE_MODE_NONE);
getListView().setTextFilterEnabled(true);
} catch (IllegalArgumentException | NullPointerException e) {
// If user starts the app and there is no accessory attached, show Toast message.
Toast.makeText(this, "no accessory detected", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onResume() {
super.onResume();
// When the onResume method is called, log that the app is setting the screen name.
Log.i(TAG, "Setting screen name: " + this.getApplication());
/*
Send data to Google Analytics
*/
mTracker.setScreenName("Image~" + this.getApplication());
mTracker.send(new HitBuilders.ScreenViewBuilder().build());
}
}
我遇到的问题是，在MainActivity的第111-112行，我正在尝试创建一个新的AnalyticsApplication类实例，并在LogCat报告中收到ClassCastException。我已经探索了几个在线论坛，发现一般的解决方案是将AnalyticsApplication类添加到AndroidManifest。但是，这并没有解决我的问题。