在android项目中用到AIDL，今天碰到了一个诡异的问题，花费了半天的时间终于解决了。具体原因有待细究
 
bindService( service, connection, BIND_AUTO_CREATE ) 之后一直不调用
connection中的onServiceConnected方法
复查了很多容易出错的问题（有问题的童鞋可以复查下面几条）：
1、服务器端的service声明，要和客户端bindService的第一个参数匹配，不然客户端启动不了这个服务。
 <service
            android:name="com.eebbk.keywordsearch.ExamCommentService"
            android:process=":remote" >
            <intent-filter>
                <!-- AIDL完整路径名。必须指明，客户端能够通过AIDL类名查找到它的实现类 -->
                <action android:name="com.eebbk.keywordsearch.ITestService" />
            </intent-filter>
  </service>
2、服务器端service必须  return实现AIDL接口ITestService.Stub   的binder
        @Override
        public IBinder onBind( Intent intent )
        {
               // TODO Auto-generated method stub
               return binder; // 返回AIDL接口实例化对象;
        }
3、如果前面两种方法都没有解决，那么很有可能就是我要提到的这个问题了，往下看
  我的问题代码如下：

import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.Log;


/**
 * Class Name: SearchClientActivity.java Function:
 * 
 * Modifications:
 * 
 * @author tm  DateTime 2013-1-23 下午4:20:20
 * @version 1.0
 */
public class SearchClientActivity extends Activity
{
	
	private static final String TAG = "SearchClientActivity";
	private ITestService tService = null;
	// 创建远程调用对象
	private ServiceConnection connection = new ServiceConnection( )
	{
		
		public void onServiceConnected( ComponentName name, IBinder service )
		{
			// TODO Auto-generated method stub
			// 从远程service中获得AIDL实例化对象
			tService = ITestService.Stub.asInterface( service );
			System.out.println( "Bind Success:" + tService );
		}
		
		public void onServiceDisconnected( ComponentName name )
		{
			// TODO Auto-generated method stub
			tService = null;
		}
	};
	
	@Override
	protected void onCreate( Bundle savedInstanceState )
	{
		// TODO Auto-generated method stub
		super.onCreate( savedInstanceState );
		setContentView( R.layout.main );
		
		Intent service = new Intent( ITestService.class.getName( ) );
		// 绑定AIDL
		bindService( service, connection, BIND_AUTO_CREATE );


		//tService为空 死循环等待异步任务结束 
		while ( tService == null )
		{
			Thread.sleep( 500 );
		}
		
		try
		{
			//在客户端调用服务器端的方法
			List< SearchResultItem > resultItems = tService.getSearchResulet( "" );
			
			for ( int i = 0; i < resultItems.size( ); i++ )
			{
				Log.i( TAG, resultItems.get( i ).getIndex( ) + resultItems.get( i ).getDetailContent( ) );
			}
		}
		catch ( RemoteException e )
		{
			// TODO Auto-generated catch block
			e.printStackTrace( );
		}
		
	}
	
	@Override
	protected void onDestroy( )
	{
		// TODO Auto-generated method stub
		super.onDestroy( );
		unbindService( connection );
	}
	
}

结果一直陷入死循环，不跑onServiceConnected方法。

解决方法：不要在onCreate中等待得到AIDL的接口服务实例，即上面代码中的tService

import java.util.List;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.Log;
import android.widget.ListView;

import com.eebbk.searchclientaidl.R;

public class SearchClientAIDLActivity extends Activity {
	
	private static final String TAG = "SearchClientAIDLActivity";

	private ITestService tService;
	
	//创建远程调用对象
	private ServiceConnection connection = new ServiceConnection(){

		public void onServiceConnected(ComponentName name, IBinder service) {
			// TODO Auto-generated method stub
			System.out.println(" onServiceConnected ");
			//从远程service中获得AIDL实例化对象
			tService = ITestService.Stub.asInterface(service);
			System.out.println("Bind Success:"+tService);
			
			new Thread( new Runnable( )
			{
				
				@Override
				public void run( )
				{
					Log.v( TAG, "开启新线程!" );
					getResults( );
				}
			} ).start( );
		}

		public void onServiceDisconnected(ComponentName name) {
			// TODO Auto-generated method stub
			tService = null;
		}
	};
	
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
                 
        Intent service = new Intent( ITestService.class.getName());
		//绑定AIDL
		bindService(service, connection, BIND_AUTO_CREATE);
		
    }

    private void getResults()
    {
		try
		{
			List< SearchResultItem > resultItems = tService.getSearchResulet( "" );
			
			for ( int i = 0; i < resultItems.size( ); i++ )
			{
				Log.i( TAG, resultItems.get( i ).getIndex( ) + resultItems.get( i ).getDetailContent( ) );
			}
		}
		catch ( RemoteException e )
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    }
    
	
	@Override
	protected void onDestroy( )
	{
		// TODO Auto-generated method stub
		super.onDestroy( );
		unbindService( connection );
	}
}

bindService的具体流程可以参考

http://blog.csdn.net/luoshengyang/article/details/6745181

#import <UIKit/UIKit.h>

@interface UIView (Positioning)

- (void)centerInRect:(CGRect)rect;
- (void)centerVerticallyInRect:(CGRect)rect;
- (void)centerHorizontallyInRect:(CGRect)rect;

- (void)centerInSuperView;
- (void)centerVerticallyInSuperView;
- (void)centerHorizontallyInSuperView;

- (void)centerHorizontallyBelow:(UIView *)view padding:(CGFloat)padding;
- (void)centerHorizontallyBelow:(UIView *)view;

@end



#import "UIView+Positioning.h"
#import "UIView+Size.h"

@implementation UIView (Positioning)

//针对给定的坐标系居中
- (void)centerInRect:(CGRect)rect;
{
    //如果参数是小数，则求最大的整数但不大于本身.
    //CGRectGetMidX获取中心点的X轴坐标
  [self setCenter:CGPointMake(floorf(CGRectGetMidX(rect)) + ((int)floorf([self width]) % 2 ? .5 : 0) , floorf(CGRectGetMidY(rect)) + ((int)floorf([self height]) % 2 ? .5 : 0))];
}

//针对给定的坐标系纵向居中
- (void)centerVerticallyInRect:(CGRect)rect;
{
  [self setCenter:CGPointMake([self center].x, floorf(CGRectGetMidY(rect)) + ((int)floorf([self height]) % 2 ? .5 : 0))];
}

//针对给定的坐标系横向居中
- (void)centerHorizontallyInRect:(CGRect)rect;
{
  [self setCenter:CGPointMake(floorf(CGRectGetMidX(rect)) + ((int)floorf([self width]) % 2 ? .5 : 0), [self center].y)];
}

//相对父视图居中
- (void)centerInSuperView;
{
  [self centerInRect:[[self superview] bounds]];
}
- (void)centerVerticallyInSuperView;
{
  [self centerVerticallyInRect:[[self superview] bounds]];
}
- (void)centerHorizontallyInSuperView;
{
  [self centerHorizontallyInRect:[[self superview] bounds]];
}

//同一父视图的兄弟视图水平居中
- (void)centerHorizontallyBelow:(UIView *)view padding:(CGFloat)padding;
{
    // for now, could use screen relative positions.
  NSAssert([self superview] == [view superview], @"views must have the same parent");
  
  [self setCenter:CGPointMake([view center].x,
                              floorf(padding + CGRectGetMaxY([view frame]) + ([self height] / 2)))];
}

- (void)centerHorizontallyBelow:(UIView *)view;
{
  [self centerHorizontallyBelow:view padding:0];
}

@end

#import <UIKit/UIKit.h>

@interface UIView (Size)

@property (nonatomic, assign) CGSize size;

@property (nonatomic, assign) CGFloat left;
@property (nonatomic, assign) CGFloat right;
@property (nonatomic, assign) CGFloat top;
@property (nonatomic, assign) CGFloat bottom;

@property (nonatomic, assign) CGFloat centerX;
@property (nonatomic, assign) CGFloat centerY;

@property (nonatomic, assign) CGFloat width;
@property (nonatomic, assign) CGFloat height;

@end


#import "UIView+Size.h"

@implementation UIView (Size)

- (void)setSize:(CGSize)size;
{
  CGPoint origin = [self frame].origin;
  
  [self setFrame:CGRectMake(origin.x, origin.y, size.width, size.height)];
}

- (CGSize)size;
{
  return [self frame].size;
}

- (CGFloat)left;
{
  return CGRectGetMinX([self frame]);
}

- (void)setLeft:(CGFloat)x;
{
  CGRect frame = [self frame];
  frame.origin.x = x;
  [self setFrame:frame];
}

- (CGFloat)top;
{
  return CGRectGetMinY([self frame]);
}

- (void)setTop:(CGFloat)y;
{
  CGRect frame = [self frame];
  frame.origin.y = y;
  [self setFrame:frame];
}

- (CGFloat)right;
{
  return CGRectGetMaxX([self frame]);
}

- (void)setRight:(CGFloat)right;
{
  CGRect frame = [self frame];
  frame.origin.x = right - frame.size.width;
  
  [self setFrame:frame];
}

- (CGFloat)bottom;
{
  return CGRectGetMaxY([self frame]);
}

- (void)setBottom:(CGFloat)bottom;
{
  CGRect frame = [self frame];
  frame.origin.y = bottom - frame.size.height;

  [self setFrame:frame];
}

- (CGFloat)centerX;
{
  return [self center].x;
}

- (void)setCenterX:(CGFloat)centerX;
{
  [self setCenter:CGPointMake(centerX, self.center.y)];
}

- (CGFloat)centerY;
{
  return [self center].y;
}

- (void)setCenterY:(CGFloat)centerY;
{
  [self setCenter:CGPointMake(self.center.x, centerY)];
}

- (CGFloat)width;
{
  return CGRectGetWidth([self frame]);
}

- (void)setWidth:(CGFloat)width;
{
  CGRect frame = [self frame];
  frame.size.width = width;

  [self setFrame:CGRectStandardize(frame)];
}

- (CGFloat)height;
{
  return CGRectGetHeight([self frame]);
}

- (void)setHeight:(CGFloat)height;
{
  CGRect frame = [self frame];
  frame.size.height = height;
  [self setFrame:CGRectStandardize(frame)];
}

@end