<ImageButton android:id="@+id/previous"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/media_skip_backward"
android:background="@drawable/transparent"></ImageButton>
这就是我试图获得透明的ImageButton以便将这些按钮放在SurfaceView上.但是,只要我在xml中包含透明线,Eclipse就会在项目中出现错误.
请帮忙.
我正在尝试创建一个GhostSurfaceCameraView扩展的自定义视图SurfaceView.这是我的类定义文件
GhostSurfaceCameraView.java:
public class GhostSurfaceCameraView extends SurfaceView implements SurfaceHolder.Callback {
SurfaceHolder mHolder;
Camera mCamera;
GhostSurfaceCameraView(Context context) {
super(context);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where to draw.
mCamera = Camera.open();
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException exception) {
mCamera.release();
mCamera = …我一直在努力在Android上制作自定义相机活动,但是当旋转相机时,表面视图的纵横比会变得混乱.
在我的oncreate活动中,我设置了framelayout,它保存了显示摄像机参数的表面视图.
//FrameLayout that will hold the camera preview
FrameLayout previewHolder = (FrameLayout) findViewById(R.id.camerapreview);
//Setting camera's preview size to the best preview size
Size optimalSize = null;
camera = getCameraInstance();
double aspectRatio = 0;
if(camera != null){
//Setting the camera's aspect ratio
Camera.Parameters parameters = camera.getParameters();
List<Size> sizes = parameters.getSupportedPreviewSizes();
optimalSize = CameraPreview.getOptimalPreviewSize(sizes, getResources().getDisplayMetrics().widthPixels, getResources().getDisplayMetrics().heightPixels);
aspectRatio = (float)optimalSize.width/optimalSize.height;
}
if(optimalSize!= null){
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, (int)(getResources().getDisplayMetrics().widthPixels*aspectRatio));
previewHolder.setLayoutParams(params);
LayoutParams surfaceParams = new LayoutParams(LayoutParams.MATCH_PARENT, (int)(getResources().getDisplayMetrics().widthPixels*aspectRatio));
cameraPreview.setLayoutParams(surfaceParams);
}
cameraPreview.setCamera(camera);
//Adding the preview …我很难理解绘制的过程,SurfaceView因此也很难理解在Android中使用的整个Surface/ Canvas/ Bitmap系统.
我已经阅读了所有文章和API文档页面,我可以在android-developers网站上找到,一些android图形教程,LunarLander源代码和这个问题.
请告诉我,这些陈述中哪些是真的,哪些不是,为什么.
Canvas有它自己的Bitmap附加.Surface有它自己的Canvas附加.View的窗口共享相同Surface,因此共享相同Canvas.SurfaceView是子类View,它与其他View子类View本身不同,它有自己Surface的绘制.还有一个问题:
Surface如果已经有一个Canvas用于位图的高级操作,为什么需要一个类.举一个Canvas不适合做Surface可以做的工作的情况的例子.为了制作一个简单的游戏,我使用了一个模板来绘制带有这样的位图的画布:
private void doDraw(Canvas canvas) {
for (int i=0;i<8;i++)
for (int j=0;j<9;j++)
for (int k=0;k<7;k++) {
canvas.drawBitmap(mBits[allBits[i][j][k]], i*50 -k*7, j*50 -k*7, null); } }
(画布在"run()"中定义/ SurfaceView存在于GameThread中.)
我的第一个问题是如何清除(或重绘)整个画布以获得新的布局？
其次,如何更新屏幕的一部分？
// This is the routine that calls "doDraw":
public void run() {
while (mRun) {
Canvas c = null;
try {
c = mSurfaceHolder.lockCanvas(null);
synchronized (mSurfaceHolder) {
if (mMode == STATE_RUNNING)
updateGame();
doDraw(c); }
} finally {
if (c != null) {
mSurfaceHolder.unlockCanvasAndPost(c); } } } }
我想根据Android中的设备方向设置相机方向,但似乎没有任何效果.我尝试旋转Surface以及相机参数,但是纵向模式下的相机预览总是颠倒过来.我需要顺时针旋转90度才能使其正确.这是我现在使用的代码,仅适用于横向模式.
SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
camera.stopPreview();
camera.release();
camera = null;
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
initCamera();
}
private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.2;
double targetRatio = (double) w / h;
if (sizes == null)
return null;
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
// Try to find an size match aspect ratio and size
for (Size size …大家好我想让我的DrawingSurface视图透明.我试了很多东西,但它不起作用.
这是我的表面视图透明的xml代码
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<FrameLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:src="@drawable/icon" >
</ImageView>
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#00000000" >
<codewalla.android.drawings.DrawingSurface
android:id="@+id/drawingSurface"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
</codewalla.android.drawings.DrawingSurface>
</LinearLayout>
</FrameLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<Button
android:id="@+id/colorRedBtn"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="10"
android:onClick="onClick"
android:text="R" />
<Button
android:id="@+id/colorBlueBtn"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="10"
android:onClick="onClick"
android:text="G" />
<Button
android:id="@+id/colorGreenBtn"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="10"
android:onClick="onClick"
android:text="B" />
<Button
android:id="@+id/undoBtn"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="10"
android:onClick="onClick"
android:text="U" />
<Button
android:id="@+id/redoBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="10"
android:onClick="onClick"
android:text="R" />
</LinearLayout>
</RelativeLayout>
我一直在尝试实现一个需要在表面上进行相机预览的应用程序.在我看到事物时,活动和表面生命周期都包含以下状态:
onResume()->onSurfaceCreated()->onSurfaceChanged()onPause()->onSurfaceDestroyed()在此方案中,我可以像打开/释放相机相应的调用和启动/停止在预览onPause/onResume和onSurfaceCreated()/onSurfaceDestroyed().
它工作正常,除非我锁定屏幕.当我启动应用程序时,然后锁定屏幕并在以后解锁它我看到:
onPause()- 屏幕锁定后没有别的 - 然后onResume()解锁后 - 之后没有表面回调.实际上,onResume()在按下电源按钮并且屏幕打开后调用,但是锁定屏幕仍然处于活动状态,因此,在活动变得均匀可见之前.
通过这种方案,我在解锁后得到一个黑屏,并且没有调用表面回调.
这是一个代码片段,不涉及相机的实际工作,而是SurfaceHolder回调.即使在我的手机上使用此代码,也会重现上述问题(按"后退"按钮时会以正常顺序调用回调,但在锁定屏幕时会丢失):
class Preview extends SurfaceView implements SurfaceHolder.Callback {
private static final String tag= "Preview";
public Preview(Context context) {
super(context);
Log.d(tag, "Preview()");
SurfaceHolder holder = getHolder();
holder.addCallback(this);
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
Log.d(tag, "surfaceCreated");
}
public void surfaceDestroyed(SurfaceHolder holder) {
Log.d(tag, "surfaceDestroyed");
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { …我有一个简单的程序,将预览绘制Camera成一个SurfaceView.我正在尝试做的是使用该onPreviewFrame方法,每次将新帧绘制到SurfaceView该invalidate方法时调用该onDraw方法,以便执行应该调用该方法的方法.事实上,该onDraw方法正在被调用,但没有任何东西被打印(我猜相机预览正在覆盖我正在尝试绘制的文本).
这是SurfaceView我所拥有的子类的简化版本:
public class Superficie extends SurfaceView implements SurfaceHolder.Callback {
SurfaceHolder mHolder;
public Camera camera;
Superficie(Context context) {
super(context);
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(final SurfaceHolder holder) {
camera = Camera.open();
try {
camera.setPreviewDisplay(holder);
camera.setPreviewCallback(new PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera arg1) {
invalidar();
}
});
} catch (IOException e) {}
}
public void invalidar(){
invalidate();
}
public void surfaceChanged(SurfaceHolder …我收到了这个错误.我尝试了很多解决方案,但我还是想解决这个问题.帮我!我需要使用片段将表面视图和按钮添加到活动中.
CamActivity.java:
public class CamActivity extends FragmentActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cam);
FragmentManager fm = getSupportFragmentManager();
Fragment fragment = fm.findFragmentById(R.id.fragmentContainer);
if(fragment == null) {
fragment = new CamFragment();
fm.beginTransaction()
.add(R.id.fragmentContainer, fragment)
.commit();
}
}
}
CamFragment.java:
public class CamFragment extends Fragment {
private static final String TAG = "CamFragment";
private Camera mCamera;
private SurfaceView mSurfaceView;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState){
View v = inflater.inflate(R.layout.camera_fragment, parent);
Button capturePic = (Button)v.findViewById(R.id.img_capture);
capturePic.setOnClickListener(new View.OnClickListener() { …android ×10
surfaceview ×10
camera ×3
aspect-ratio ×1
class ×1
imagebutton ×1
java ×1
orientation ×1
preview ×1
transparent ×1
xml ×1