叠加图像按钮不可见 (Android)
Overlay image button is invisible (Android)
我想在我的相机应用程序的相机预览顶部叠加一个图像按钮,这样相机预览就可以占据整个屏幕,用户仍然可以拍照。
我的activity_camera.xml是:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal">
<FrameLayout
android:id="@+id/preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/camera_photo"
android:id="@+id/take_photoimageButton"
android:visibility="visible"
android:layout_gravity="center_horizontal|bottom" />
</FrameLayout>
</LinearLayout>
有没有一种方法可以编辑布局,以便在相机预览时按钮可见?
编辑 -
这是我的预览 class:
class Preview extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = "Preview";
SurfaceHolder mHolder;
public Camera camera;
Preview(Context context, Camera inCamera) {
super(context);
camera = inCamera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
try {
camera.setPreviewDisplay(holder);
camera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void OLDsurfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
// camera = Camera.open();
camera.setDisplayOrientation(90);
try {
camera.setPreviewDisplay(holder);
// camera.setPreviewCallback(new PreviewCallback() {
//
// public void onPreviewFrame(byte[] data, Camera arg1) {
// FileOutputStream outStream = null;
// try {
// outStream = new FileOutputStream(String.format(
// "/sdcard/%d.jpg", System.currentTimeMillis()));
// outStream.write(data);
// outStream.close();
// Log.d(TAG, "onPreviewFrame - wrote bytes: "
// + data.length);
// } catch (FileNotFoundException e) {
// e.printStackTrace();
// } catch (IOException e) {
// e.printStackTrace();
// } finally {
// }
// Preview.this.invalidate();
// }
// });
} catch (IOException e) {
e.printStackTrace();
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the preview.
// Because the CameraDevice object is not a shared resource, it's very
// important to release it when the activity is paused.
camera.stopPreview();
camera.release();
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
camera.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
camera.setPreviewDisplay(mHolder);
camera.startPreview();
} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
public void OLDsurfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = camera.getParameters();
//parameters.setPreviewSize(w, h);
//camera.setParameters(parameters);
List<Camera.Size> sizes = parameters.getSupportedPreviewSizes();
Camera.Size cs = sizes.get(0);
parameters.setPreviewSize(cs.width, cs.height);
//parameters.setRotation(90);
camera.setParameters(parameters);
camera.startPreview();
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
Paint p = new Paint(Color.RED);
Log.d(TAG, "draw");
canvas.drawText("PREVIEW", canvas.getWidth() / 2,
canvas.getHeight() / 2, p);
}
}
假设您在代码中为预览创建了一个 SurfaceView,并使用 addView() 将其添加到预览 FrameLayout,将您的布局更改为:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal">
<FrameLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<FrameLayout
android:id="@+id/preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!-- Empty layout where SurfaceView will be placed in code-->
</FrameLayout>
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/camera_photo"
android:id="@+id/take_photoimageButton"
android:visibility="visible"
android:layout_gravity="center_horizontal|bottom" />
</FrameLayout>
</LinearLayout>
就 z 顺序而言,布局中后面声明的视图绘制在前面声明的视图之上,代码中添加的视图绘制在顶部,就好像它们已添加到布局的末尾一样(除非您指定一个索引)。放置一个空布局以添加 SurfaceView 以允许它在 ImageButton 下绘制。
或者您可以尝试使用索引 0 调用 addView(),但是问题是询问如何在布局中实现此目的 XML。
除非出于某些其他原因需要使用 LinearLayout,否则您可以去掉它并使外部 FrameLayout 成为顶级 ViewGroup。
我想在我的相机应用程序的相机预览顶部叠加一个图像按钮,这样相机预览就可以占据整个屏幕,用户仍然可以拍照。
我的activity_camera.xml是:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal">
<FrameLayout
android:id="@+id/preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/camera_photo"
android:id="@+id/take_photoimageButton"
android:visibility="visible"
android:layout_gravity="center_horizontal|bottom" />
</FrameLayout>
</LinearLayout>
有没有一种方法可以编辑布局,以便在相机预览时按钮可见?
编辑 - 这是我的预览 class:
class Preview extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = "Preview";
SurfaceHolder mHolder;
public Camera camera;
Preview(Context context, Camera inCamera) {
super(context);
camera = inCamera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
try {
camera.setPreviewDisplay(holder);
camera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void OLDsurfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
// camera = Camera.open();
camera.setDisplayOrientation(90);
try {
camera.setPreviewDisplay(holder);
// camera.setPreviewCallback(new PreviewCallback() {
//
// public void onPreviewFrame(byte[] data, Camera arg1) {
// FileOutputStream outStream = null;
// try {
// outStream = new FileOutputStream(String.format(
// "/sdcard/%d.jpg", System.currentTimeMillis()));
// outStream.write(data);
// outStream.close();
// Log.d(TAG, "onPreviewFrame - wrote bytes: "
// + data.length);
// } catch (FileNotFoundException e) {
// e.printStackTrace();
// } catch (IOException e) {
// e.printStackTrace();
// } finally {
// }
// Preview.this.invalidate();
// }
// });
} catch (IOException e) {
e.printStackTrace();
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the preview.
// Because the CameraDevice object is not a shared resource, it's very
// important to release it when the activity is paused.
camera.stopPreview();
camera.release();
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
camera.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
camera.setPreviewDisplay(mHolder);
camera.startPreview();
} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
public void OLDsurfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = camera.getParameters();
//parameters.setPreviewSize(w, h);
//camera.setParameters(parameters);
List<Camera.Size> sizes = parameters.getSupportedPreviewSizes();
Camera.Size cs = sizes.get(0);
parameters.setPreviewSize(cs.width, cs.height);
//parameters.setRotation(90);
camera.setParameters(parameters);
camera.startPreview();
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
Paint p = new Paint(Color.RED);
Log.d(TAG, "draw");
canvas.drawText("PREVIEW", canvas.getWidth() / 2,
canvas.getHeight() / 2, p);
}
}
假设您在代码中为预览创建了一个 SurfaceView,并使用 addView() 将其添加到预览 FrameLayout,将您的布局更改为:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal">
<FrameLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<FrameLayout
android:id="@+id/preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!-- Empty layout where SurfaceView will be placed in code-->
</FrameLayout>
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/camera_photo"
android:id="@+id/take_photoimageButton"
android:visibility="visible"
android:layout_gravity="center_horizontal|bottom" />
</FrameLayout>
</LinearLayout>
就 z 顺序而言,布局中后面声明的视图绘制在前面声明的视图之上,代码中添加的视图绘制在顶部,就好像它们已添加到布局的末尾一样(除非您指定一个索引)。放置一个空布局以添加 SurfaceView 以允许它在 ImageButton 下绘制。
或者您可以尝试使用索引 0 调用 addView(),但是问题是询问如何在布局中实现此目的 XML。
除非出于某些其他原因需要使用 LinearLayout,否则您可以去掉它并使外部 FrameLayout 成为顶级 ViewGroup。