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我正在实现一个具有服务和活动的android软件，并且我根据youtube视频做了一些代码。但是，当我点击开始按钮，运行按钮他们工作正常。但是，我重新启动服务后（按停止，然后再按启动）程序崩溃。所以任何人都可以帮助我来解决这个问题。Android Activity Service Communication
也有任何方式在Android做服务和活动之间的双向沟通？ （例如： - 服务获取GPS位置和更改位置0.001，然后ui自动显示编辑后的位置）
请有些人帮我弄清楚这一点。
我的代码： -
MyActivity.java
package com.example.autocomplete.servicemessenger;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;
public class MyActivity extends Activity {
boolean status=false;
Messenger msngr=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.my, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void startMethod(View v){
if (status){
Toast.makeText(getApplicationContext(), "already started", Toast.LENGTH_SHORT).show();
}
else {
Intent i = new Intent(this, MyService.class);
bindService(i, mConnection, Context.BIND_AUTO_CREATE);
status = true;
Toast.makeText(getApplicationContext(), "start", Toast.LENGTH_SHORT).show();
}
}
public void stoptMethod(View v){
if (status) {
Intent i = new Intent(this, MyService.class);
unbindService(mConnection);
stopService(i);
mConnection = null;
status = false;
Toast.makeText(getApplicationContext(), "stop", Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(getApplicationContext(), "already stopped", Toast.LENGTH_SHORT).show();
}
}
public void runMethod(View v){
Message ms=Message.obtain(null,1,0,0,0);
String s="This is the message by Activity";
Bundle bn=new Bundle();
bn.putString("my_string",s);
ms.setData(bn);
try {
msngr.send(ms);
} catch (RemoteException e) {
e.printStackTrace();
}
}
ServiceConnection mConnection=new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName componentName, IBinder service) {
msngr=new Messenger(service);
status=true;
}
@Override
public void onServiceDisconnected(ComponentName componentName) {
msngr=null;
status=false;
Toast.makeText(getApplicationContext(),"Disc",Toast.LENGTH_SHORT).show();
}
};
}
MyService.java
package com.example.autocomplete.servicemessenger;
import android.app.Service;
import android.content.Intent;
import android.os.Bundle;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.text.format.Time;
import android.widget.Toast;
import java.util.logging.Handler;
/**
* Created by NRV on 9/3/2014.
*/
public class MyService extends Service {
int val=1;
@Override
public IBinder onBind(Intent intent) {
return msgnr.getBinder();
}
@Override
public boolean onUnbind(Intent intent) {
stopSelf();
return super.onUnbind(intent);
}
class MessageHandler extends android.os.Handler{
public void handleMessage(Message msg){
if (msg.what==val){
Toast.makeText(getBaseContext(),"I am toast in service",Toast.LENGTH_SHORT).show();
Bundle bundle=msg.getData();
String msg_snt=bundle.getString("my_string");
Toast.makeText(getApplicationContext(),"I recv : "+msg_snt,Toast.LENGTH_SHORT).show();
}
else{
super.handleMessage(msg);
}
}
}
Messenger msgnr=new Messenger(new MessageHandler());
}
activity_my.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MyActivity">
<TextView
android:text="@string/hello_world"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/textView"
/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Start"
android:id="@+id/button"
android:layout_below="@+id/textView"
android:layout_marginTop="93dp"
android:layout_toLeftOf="@+id/button2"
android:onClick="startMethod"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Stop"
android:id="@+id/button2"
android:layout_below="@+id/button"
android:layout_alignParentRight="true"
android:layout_marginRight="106dp"
android:onClick="stoptMethod"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Run"
android:id="@+id/button3"
android:layout_below="@+id/button2"
android:layout_alignParentLeft="true"
android:onClick="runMethod"/>
</RelativeLayout>