来源: 互联网  发布时间: 2014-02-18

烦，surfaceview 回调咋回事

访问SurfaceView的底层图形是通过SurfaceHolder接口来实现的，通过getHolder()方法可以得到这个SurfaceHolder对象。你应该实现surfaceCreated(SurfaceHolder)和surfaceDestroyed(SurfaceHolder)方法来知道在这个Surface在窗口的显示和隐藏过程中是什么时候创建和销毁的。
SurfaceView可以在多线程中被访问。
注意：一个SurfaceView只在SurfaceHolder.Callback.surfaceCreated() 和 SurfaceHolder.Callback.surfaceDestroyed()调用之间是可用的，其他时间是得不到它的Canvas对象的（null）。

我的访问过程：
创建一个SurfaceView的子类，实现SurfaceHolder.Callback接口。
得到这个SurfaceView的SurfaceHolder对象holder。
holder.addCallback(callback)，也就是实现SurfaceHolder.Callback接口的类对象。
在SurfaceHolder.Callback.surfaceCreated()调用过后holder.lockCanvas()对象就可以得到SurfaceView对象对应的Canvas对象canvas了。
用canvas对象画图。
画图结束后调用holder.unlockCanvasAndPost()就把图画在窗口中了。
SurfaceView可以多线程访问，在多线程中画图。


import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MySurfaceView extends SurfaceView implements
SurfaceHolder.Callback {


private Context mContext;
private SurfaceHolder mHolder;

public TouchScreenAdjusterSurfaceView(Context context,) {
super(context);

mContext = context;

mHolder = TouchScreenAdjusterSurfaceView.this.getHolder();
mHolder.addCallback(TouchScreenAdjusterSurfaceView.this);

this.setFocusableInTouchMode(true); // to make sure that we can get
// touch events and key events,and
// "setFocusable()" to make sure we
// can get key events
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub

}

@Override
public void surfaceCreated(SurfaceHolder holder) {
//now you can get the Canvas and draw something here
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub

}


public void drawMyShape(PointPostion ps) {

mCanvas = mHolder.lockCanvas();

// draw anything you like

mHolder.unlockCanvasAndPost(mCanvas);
}

}


最近碰到以怪事，surfaceView.callback的surfaceCreated死活不能执行，不知道怎么搞，到处搜搜，把东西贴上来，慢慢研究，不知哪位高手能介绍下surfaceview回调函数的运行原理，什么时候加载，什么时候结束，郁闷，搞这个回调现在只能碰运气，烦死了

    

    来源: 互联网  发布时间: 2014-02-18

判断联系人Contacts的版本问题

Intent intent = null;
                        ClassLoader classLoader = DialerContactList.class.getClassLoader();
                        try
                        {
                                classLoader.loadClass("android.provider.ContactsContract");
                                intent = new Intent(Intent.ACTION_PICK,Uri.parse("content://
com.android.contacts/data/phones"));
                        }
                        catch (ClassNotFoundException e)
                        {
                        }
                        if (intent == null)
                        {
                                intent = new Intent(Intent.ACTION_PICK,Phones.CONTENT_URI);
                        }
                        startActivityForResult(intent, ADD_CONTACT);

    

    来源: 互联网  发布时间: 2014-02-18

Enum常量放入NSArray的方法

ypedef enum {
    UIViewAnimationCurveEaseInOut,
    UIViewAnimationCurveEaseIn = 0,
    UIViewAnimationCurveEaseOut,
    UIViewAnimationCurveLinear
} UIViewAnimationCurve;

This result of this would be: UIViewAnimationCurveEaseInOut is 0; UIViewAnimationCurveEaseIn is 0; UIViewAnimationCurveEaseOut is 1; and so on. However, for basic purposes you shouldn't need to do anything like that; it just gives you some useful info to toy with.

It should be noted based on the above, that an enum can't assume to be a unique value; different enum identifiers can be equal in value to each other.

Adding an enum item to a NSArray is as simple as adding an integer. The only difference would be that you use the enum identifer instead.

[myArray addObject:[NSNumber numberWithInt:UIViewAnimationCurveEaseInOut]];