我正在尝试通过XML向相机的预览框添加一个按钮，虽然一切正常，但即使我从代码中添加按钮后按钮也不显示。谁能帮帮我吗？以下是我的代码的一部分：
主要课程：
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
dummy = (Button)findViewById(R.id.dummy); //adding button
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
mContext = this;
mPreview = new Preview(this);
setContentView(mPreview);
manager = new CameraConfigurationManager(this);
display = ((WindowManager) this.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
screenResolution = new Point(display.getWidth(), display.getHeight());
rect = getFramingRect();
mDraw = new DrawOnTop(this, rect);
addContentView(mDraw, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
}
我的main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:orientation="vertical">
<SurfaceView android:id="@+id/surface_camera"
android:layout_width="fill_parent" android:layout_height="10dip"
android:layout_weight="1">
</SurfaceView>
<Button android:id="@+id/dummy"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="a Button" />
</LinearLayout>
预览课程：
public class Preview extends ViewGroup implements SurfaceHolder.Callback {
private final String TAG = "Preview";
SurfaceView mSurfaceView;
SurfaceHolder mHolder;
Size mPreviewSize;
List<Size> mSupportedPreviewSizes;
Camera mCamera;
public Preview(Context context) {
super(context);
mSurfaceView = new SurfaceView(context);
addView(mSurfaceView);
mHolder = mSurfaceView.getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public Preview(Context context, AttributeSet attrs) {
super(context);
mSurfaceView = new SurfaceView(context);
addView(mSurfaceView);
mHolder = mSurfaceView.getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void setCamera(Camera camera) {
mCamera = camera;
if(mCamera != null) {
mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
requestLayout();
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(width, height);
if(mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
}
protected void onLayout(boolean changed, int l, int t, int r, int b) {
if (changed && getChildCount() > 0) {
final View child = getChildAt(0);
final int width = r - l;
final int height = b - t;
int previewWidth = width;
int previewHeight = height;
if(mPreviewSize != null) {
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
}
if(width*previewHeight > height * previewWidth) {
final int scaledChildWidth = previewWidth * height / previewHeight;
child.layout(((width) - scaledChildWidth) /2, 0, ((width) + scaledChildWidth) /2, height);
}
else {
final int scaledChildHeight = previewHeight * width / previewWidth;
child.layout(0, ((height)-scaledChildHeight) / 2, width, ((height) + scaledChildHeight) /2);
}
}
}
public void surfaceCreated(SurfaceHolder holder) {
try {
if(mCamera != null) {
mCamera.setPreviewDisplay(holder);
}
}
catch (IOException exception) {
}
}
Camera.PreviewCallback mPreviewCallback = new Camera.PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera camera) {
//test1 = 8889898;
//throw new UnsupportedOperationException("Not supported yet.");
int ARRAY_LENGTH = mPreviewSize.width*mPreviewSize.height*3/2;
int argb8888[] = new int[ARRAY_LENGTH];
decodeYUV(argb8888, data, mPreviewSize.width, mPreviewSize.height);
Bitmap bitmap = Bitmap.createBitmap(argb8888, mPreviewSize.width, mPreviewSize.height, Config.ARGB_8888);
FileOutputStream fos;
try {
fos = new FileOutputStream(String.format("/sdcard/testImage/%d.jpg", System.currentTimeMillis()));
BufferedOutputStream bos = new BufferedOutputStream(fos);
bitmap.compress(CompressFormat.JPEG, 75, bos);
try {
bos.flush();
} catch (IOException ex) {
Logger.getLogger(Preview.class.getName()).log(Level.SEVERE, null, ex);
}
bos.close();
fos.close();
} catch (FileNotFoundException ex) {
Logger.getLogger(Preview.class.getName()).log(Level.SEVERE, null, ex);
}
catch (IOException ex) {
Logger.getLogger(Preview.class.getName()).log(Level.SEVERE, null, ex);
}
}
};
// decode Y, U, and V values on the YUV 420 buffer described as YCbCr_422_SP by Android
// David Manpearl 081201
public void decodeYUV(int[] out, byte[] fg, int width, int height)
throws NullPointerException, IllegalArgumentException {
int sz = width * height;
if (out == null)
throw new NullPointerException("buffer out is null");
if (out.length < sz)
throw new IllegalArgumentException("buffer out size " + out.length
+ " < minimum " + sz);
if (fg == null)
throw new NullPointerException("buffer 'fg' is null");
if (fg.length < sz)
throw new IllegalArgumentException("buffer fg size " + fg.length
+ " < minimum " + sz * 3 / 2);
int i, j;
int Y, Cr = 0, Cb = 0;
for (j = 0; j < height; j++) {
int pixPtr = j * width;
final int jDiv2 = j >> 1;
for (i = 0; i < width; i++) {
Y = fg[pixPtr];
if (Y < 0)
Y += 255;
if ((i & 0x1) != 1) {
final int cOff = sz + jDiv2 * width + (i >> 1) * 2;
Cb = fg[cOff];
if (Cb < 0)
Cb += 127;
else
Cb -= 128;
Cr = fg[cOff + 1];
if (Cr < 0)
Cr += 127;
else
Cr -= 128;
}
int R = Y + Cr + (Cr >> 2) + (Cr >> 3) + (Cr >> 5);
if (R < 0)
R = 0;
else if (R > 255)
R = 255;
int G = Y - (Cb >> 2) + (Cb >> 4) + (Cb >> 5) - (Cr >> 1)
+ (Cr >> 3) + (Cr >> 4) + (Cr >> 5);
if (G < 0)
G = 0;
else if (G > 255)
G = 255;
int B = Y + Cb + (Cb >> 1) + (Cb >> 2) + (Cb >> 6);
if (B < 0)
B = 0;
else if (B > 255)
B = 255;
out[pixPtr++] = 0xff000000 + (B << 16) + (G << 8) + R;
}
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
if(mCamera != null) {
mCamera.stopPreview();
}
}
private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double)w/h;
if(sizes==null) {
return null;
}
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
for(Size size : sizes) {
double ratio = (double) size.width/size.height;
if(Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
if(Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
if(optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if(Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
//mCamera.setDisplayOrientation(90);
requestLayout();
//mCamera.setPreviewCallback(mPreviewCallback);
mCamera.setParameters(parameters);
mCamera.startPreview();
}
}
答案 0 :(得分：0)
使用相对布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/layout">
<LinearLayout
android:id="@+id/preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal"
android:visibility="visible"
android:layout_alignParentTop="true">
</LinearLayout>
<Button android:text="Freeze" android:id="@+id/someButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</Button>
</RelativeLayout>
然后在setContentView函数中使用addView和onCreate的组合。
public void onCreate(Bundle savedInstanceState) {
Log.i(TAG, "onCreate");
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
mPreview = new Preview(this);
LinearLayout ll = (LinearLayout)findViewById(R.id.preview);
if(ll != null)
{
ll.addView(mPreview);
}
}