自定义控件（类似按钮等）的使用，自定义一个SurfaceView。
如某一块的动态图（自定义相应），或者类似UC浏览器下面的工具栏。
如下图示例：
自定义类代码：
[java]
public class ImageSurfaceView extends SurfaceView implements Callback{
//用于控制SurfaceView
private SurfaceHolder sfh;
private Handler handler = new Handler();
private ImageRunnable imageRunnable = new ImageRunnable();
private Paint paint;
private Canvas canvas;
private Matrix matrix;
/**图片的坐标*/
private float imageX, imageY;
/**获取的图片*/
private Bitmap bmp;
/**图片宽高*/
private float bmpW, bmpH;
/**屏幕大小*/
private int screenW, screenH;
/**
* SurfaceView初始化函数
*/
public ImageSurfaceView(Context context, AttributeSet attrs) {
super(context, attrs);
sfh = this.getHolder();
sfh.addCallback(this);
paint = new Paint();
paint.setColor(Color.WHITE);
paint.setAntiAlias(true);
setFocusable(true);
}
/**
* SurfaceView视图创建，响应此函数
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
System.out.println("ImageSurfaceView is surfaceCreated");
screenH = this.getHeight();
screenW = this.getWidth();
handler.post(imageRunnable);
}
/**
* 游戏绘图
*/
public void draw() {
try {
canvas = sfh.lockCanvas();
canvas.drawRGB(0, 0, 0);
canvas.save();
//绘制
canvas.drawBitmap(bmp, matrix, paint);
System.out.println("绘制图像了吗？");
canvas.restore();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}
/**
* 触屏事件监听
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
return true;
}
/**
* 图片的线程运行
*/
class ImageRunnable implements Runnable{
@Override
public void run() {
long start = System.currentTimeMillis();
draw();
long end = System.currentTimeMillis();
if (end - start < 500) {
handler.postDelayed(this, 200 - (end-start));
}else{
handler.post(this);
}
}
}
/**
* SurfaceView视图状态发生改变，响应此函数
*/
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
System.out.println("ImageSurfaceView is surfaceChanged");
}
/**
* SurfaceView视图消亡时，响应此函数
*/
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
System.out.println("ImageSurfaceView is surfaceDestroyed");
}
}
public class ImageSurfaceView extends SurfaceView implements Callback{
//用于控制SurfaceView
private SurfaceHolder sfh;
private Handler handler = new Handler();
private ImageRunnable imageRunnable = new ImageRunnable();
private Paint paint;
private Canvas canvas;
private Matrix matrix;
/**图片的坐标*/
private float imageX, imageY;
/**获取的图片*/
private Bitmap bmp;
/**图片宽高*/
private float bmpW, bmpH;
/**屏幕大小*/
private int screenW, screenH;
/**
* SurfaceView初始化函数
*/
public ImageSurfaceView(Context context, AttributeSet attrs) {
super(context, attrs);
sfh = this.getHolder();
sfh.addCallback(this);
paint = new Paint();
paint.setColor(Color.WHITE);
paint.setAntiAlias(true);
setFocusable(true);
}
/**
* SurfaceView视图创建，响应此函数
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
System.out.println("ImageSurfaceView is surfaceCreated");
screenH = this.getHeight();
screenW = this.getWidth();
handler.post(imageRunnable);
}
/**
* 游戏绘图
*/
public void draw() {
try {
canvas = sfh.lockCanvas();
canvas.drawRGB(0, 0, 0);
canvas.save();
//绘制
canvas.drawBitmap(bmp, matrix, paint);
System.out.println("绘制图像了吗？");
canvas.restore();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}
/**
* 触屏事件监听
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
return true;
}
/**
* 图片的线程运行
*/
class ImageRunnable implements Runnable{
@Override
public void run() {
long start = System.currentTimeMillis();
draw();
long end = System.currentTimeMillis();
if (end - start < 500) {
handler.postDelayed(this, 200 - (end-start));
}else{
handler.post(this);
}
}
}
/**
* SurfaceView视图状态发生改变，响应此函数
*/
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
System.out.println("ImageSurfaceView is surfaceChanged");
}
/**
* SurfaceView视图消亡时，响应此函数
*/
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
System.out.println("ImageSurfaceView is surfaceDestroyed");
}
}
layout的xml代码如下（使用方法，类的全地址做为控件名）：
[java]
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<akai.test.getImage.ImageSurfaceView android:id="@+id/myImageView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
<LinearLayout android:id="@+id/buttons"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:background="@android:color/white"
>
<Button android:id="@+id/getImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="选择图片"
/>
<Button android:id="@+id/getImage_ok"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="确定"
/>
<Button android:id="@+id/getImage_cancle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="取消"
/>
</LinearLayout>
</FrameLayout>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<akai.test.getImage.ImageSurfaceView android:id="@+id/myImageView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
<LinearLayout android:id="@+id/buttons"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:background="@android:color/white"
>
<Button android:id="@+id/getImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="选择图片"
/>
<Button android:id="@+id/getImage_ok"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="确定"
/>
<Button android:id="@+id/getImage_cancle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="取消"
/>
</LinearLayout>
</FrameLayout>
以上代码为例子，仅供参考！
注意以下问题：
1、本类的初始化函数需要加入参数，为：public ImageSurfaceView(Context context, AttributeSet attrs) ；
2、不要在初始化的时候获取screen的宽度和高度，在初始化的时候并还没有执行SurfaceCreated，所以获取宽度和高度要在surfaceCreated或者之后，且在surfaceDestroyed之前；
3、在显示本控件的时候，会执行surfaceCreated和surfaceChanged，当跳转到其他界面的时候则执行surfaceDestroyed（不管是否当前的activity已经销毁），所以如果在跳转回到次控件的时候立刻执行sfh.lockCanvas()的话将会获得空值Null。
摘自 阿凯的专栏
