Question

我尝试创建一个监视手机状态的后台进程，并在状态发生变化时显示Toast消息。到目前为止，我已经实现了这些，但是当我安装并运行时。它什么都不做。它不会显示任何东西。我在这里发布我的代码。请帮助我。

StateMonitor.java

`

import android.content.Context;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.widget.Toast;

public class PhoneStateMonitor extends PhoneStateListener {
    Context context;

    public PhoneStateMonitor(Context context) {
        super();
        // TODO Auto-generated constructor stub
        this.context=context;
    }

    //This Method Automatically called when changes is detected in Phone State
    public void onCallStateChanged(int state, String incomingNumber) {
        // TODO Auto-generated method stub
        super.onCallStateChanged(state, incomingNumber);

        Toast.makeText(context, "Phone State - "+state+" Incoming Number - "+incomingNumber, Toast.LENGTH_LONG).show();//Giving the Message that Phone State Changed
        //Checking The phone state  
        switch(state)
        {
        case TelephonyManager.CALL_STATE_IDLE:    //Phone is in Idle State
            Toast.makeText(context, "Phone State is IDLE", Toast.LENGTH_LONG).show();
            break;
        case TelephonyManager.CALL_STATE_RINGING:  //Phone is Ringing
            Toast.makeText(context, "Phone State is RINGING", Toast.LENGTH_LONG).show();
            break;
        case TelephonyManager.CALL_STATE_OFFHOOK:  //Call is Received
            Toast.makeText(context, "Call State is OFFHOOK",Toast.LENGTH_LONG).show();
            break;
        }
    }
}
`

PhoneReceiver.java

`import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
//Automatically called when State Change is Detected because this Receiver is Registered for PHONE_STATE intent filter in AndroidManifest.xml
public class PhoneStateReceiver extends BroadcastReceiver {

    TelephonyManager manager;       
    PhoneStateMonitor phoneStateListener;
    static boolean isAlreadyListening=false;

    //This Method automatically Executed when Phone State Change is Detected
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        phoneStateListener =new PhoneStateMonitor(context);//Creating the Object of Listener
        manager=(TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE);//Getting the Telephony Service Object
        if(!isAlreadyListening)//Checking Listener is Not Registered with Telephony Services
        {
              manager.listen(phoneStateListener, PhoneStateListener.LISTEN_CALL_STATE);//Registering the Listener with Telephony to listen the State Change
          isAlreadyListening=true;  //setting true to indicate that Listener is listening the Phone State
        }

    }

}
`

Android Manifest.xml

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

    <uses-sdk
        android:minSdkVersion="10"
        android:targetSdkVersion="21" />

<uses-permission android:name="android.permission.READ_PHONE_STATE" /><!-- Permission for Reading Phone State -->
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >

        <!--  If this app is not running then this will be automatically called when phone state change detected(Look at Intent Filter) -->
        <receiver android:name=".PhoneStateReceiver">
            <intent-filter>
                <action android:name="android.intent.action.PHONE_STATE"/>
            </intent-filter>
            </receiver>
    </application>

</manifest>`

当我从eclipse安装时，它说apk安装。当我拨打我的电话时，Toast消息不会弹出。我哪里错了？请帮忙！谢谢！

Answer 1

安装应用程序时，它会保持stopped状态，直到您使用某些UI控件启动应用程序（即Activity）。它从Android 3.1 APIs (API 12)开始成为必修课。

最终，除了Activity之外，您的应用程序中至少需要一个BroadcastReceiver才能将您的应用移出该stopped州。否则它将不会收到任何广播。

<强>参考：

Launch Controls

android：后台手机状态监控

1 个答案: