Question

Problem: AutoStart On Boot Up causing classcastexception.. 

I am doing Location based application , I want to run the app whenever the phone bootup,So that my app will be running continuously, I just want to start the service as soon as the phone loads all the service.

我已经编写了广播接收方法，并且在mainfest xml中甚至设置了接收方和权限我正在编写以下代码，但我收到运行时错误，我甚至试图删除活动并运行，但它导致错误。请给我一些解决方案。

MainFest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.omkar_gpslocation"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.BATTERY_STATS" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
       <activity
            android:name="com.example.omkar_gpslocation.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.example.omkar_gpslocation.Activity_Settings"
            android:label="@string/title_activity_activity__settings" >
        </activity> 


<receiver android:enabled="true" android:name="com.example.omkar_gpslocation.MainActivity"
        android:permission="android.permission.RECEIVE_BOOT_COMPLETED">

        <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
                <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
</receiver>
    </application>

</manifest>

MainActivity

private BroadcastReceiver MyReceiver= new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        Intent serviceIntent = new Intent("com.example.omkar_gpslocation");
        context.startService(serviceIntent); 

    }
};

logcat的：

02-04 13:21:08.462: E/AndroidRuntime(503): FATAL EXCEPTION: main
02-04 13:21:08.462: E/AndroidRuntime(503): java.lang.RuntimeException: Unable to instantiate receiver com.example.omkar_gpslocation.MainActivity: java.lang.ClassCastException: com.example.omkar_gpslocation.MainActivity
02-04 13:21:08.462: E/AndroidRuntime(503):  at android.app.ActivityThread.handleReceiver(ActivityThread.java:1873)
02-04 13:21:08.462: E/AndroidRuntime(503):  at android.app.ActivityThread.access$2400(ActivityThread.java:155)
02-04 13:21:08.462: E/AndroidRuntime(503):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1049)
02-04 13:21:08.462: E/AndroidRuntime(503):  at android.os.Handler.dispatchMessage(Handler.java:130)
02-04 13:21:08.462: E/AndroidRuntime(503):  at android.os.Looper.loop(SourceFile:351)
02-04 13:21:08.462: E/AndroidRuntime(503):  at android.app.ActivityThread.main(ActivityThread.java:3820)
02-04 13:21:08.462: E/AndroidRuntime(503):  at java.lang.reflect.Method.invokeNative(Native Method)
02-04 13:21:08.462: E/AndroidRuntime(503):  at java.lang.reflect.Method.invoke(Method.java:538)
02-04 13:21:08.462: E/AndroidRuntime(503):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:969)
02-04 13:21:08.462: E/AndroidRuntime(503):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:727)
02-04 13:21:08.462: E/AndroidRuntime(503):  at dalvik.system.NativeStart.main(Native Method)
02-04 13:21:08.462: E/AndroidRuntime(503): Caused by: java.lang.ClassCastException: com.example.omkar_gpslocation.MainActivity
02-04 13:21:08.462: E/AndroidRuntime(503):  at android.app.ActivityThread.handleReceiver(ActivityThread.java:1864)
02-04 13:21:08.462: E/AndroidRuntime(503):  ... 10 more

Answer 1

您必须在自己的班级中编写您的Receiver。不要将其写为活动中的字段。

如果要在Manifest文件中注册接收器，则必须在其自己的文件中。创建一个在新文件中扩展BroadcastReceiver的新类。然后使用此类的名称作为清单中的接收者名称，而不是MainActivity。

Answer 2

如果你在清单中声明一个接收器，那么它必须在它自己的java文件中。这里你是以编程方式在活动中创建接收器的实例，所以要么通过registerReceiver方法以编程方式注册它，要么在另一个文件中创建并给出名称android中的那个文件：接收者标签的名称。

Answer 3

对于有问题的每个人：

如何在没有广播的情况下接收广播清单并以编程方式在活动中声明。

将接收器写为您活动的内部类。
在活动的onResume方法中注册接收者
在onPause方法中取消注册接收器

即

public class Simpleclass extends Activity
{
    public final String ACTION_BROADCAST = "com.example.intent.action.something";
    private aBroadcastReceiver mReceiver;

    private class aBroadcastReceiver extends BroadcastReceiver
        {
            @Override
            public void onReceive(Context context, Intent intent)
            {
                foo();
                //do something  
            }

        }

        //[...]

        @Override
        public void onPause()
        {
            getApplicationContext().unregisterReceiver(mReceiver);
            super.onPause();
        }

        @Override
        public void onResume()
        {
            final IntentFilter intentFilter = new IntentFilter(mReceiver);
            mReceiver= new aBroadcastReceiver();
            getApplicationContext().registerReceiver(mReceiver, intentFilter);
            super.onResume();
        }
}

发送广播：

final Intent broadcast = new Intent(Simpleclass.ACTION_BROADCAST);
getApplicationContext().sendBroadcast(broadcast);

无法实例化接收器，java.lang.ClassCastException

3 个答案: