我正在尝试创建一个布局，该布局在顶部包含一个“SurfaceView”，其水平工具栏在底部分为 3 个部分，但是包含相机预览的 SurfaceView 只是唯一显示的元素。请指出我的布局 xml 中的错误或提供类似的布局 xml，谢谢。
以下是我根据用户推荐的布局和更新
尝试＃1（RelativeLayout 作为根）：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/LayoutForPreview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:screenOrientation="portrait" >
<SurfaceView
android:id="@+id/surfaceViewBarcodeScanner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="@+id/linearLayoutToolbar"
android:layout_gravity="top"
android:scaleType="fitXY" />
<LinearLayout
android:id="@+id/linearLayoutToolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:orientation="horizontal" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_left" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.68"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_center_toolbar" />
<ImageView
android:id="@+id/imageView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_right_landscape_button" />
</LinearLayout>
</RelativeLayout>
下面是我想要的 GUI 外观：
尝试 #1 结果，设备快照，仅显示 SurfaceView：
eclipse GUI 工具的快照，它显示了布局应该是什么样子。
尝试 #2（LinearLayout 作为根）：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/LayoutForPreview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:screenOrientation="portrait" >
<SurfaceView
android:id="@+id/surfaceViewBarcodeScanner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:scaleType="fitXY"
android:layout_weight="1" />
<LinearLayout
android:id="@+id/linearLayoutToolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_gravity="bottom" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_left" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.68"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_center_toolbar" />
<ImageView
android:id="@+id/imageView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_right_landscape_button" />
</LinearLayout>
</LinearLayout>
尝试#2，结果，设备快照：
问题：
1) 工具栏出现在顶部而不是底部
2）相机预览冻结和应用程序崩溃。由于某种原因 LinearLayout 导致相机错误 1001 ，我认为它与预览尺寸有关。
尝试 #3（以编程方式将工具栏添加到活动 onCreate 中的相对或线性布局）。
线性布局：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/LayoutForPreview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:screenOrientation="portrait" >
<SurfaceView
android:id="@+id/surfaceViewBarcodeScanner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:scaleType="fitXY"
android:layout_weight="1" />
</LinearLayout>
稍后通过 Java 代码添加的单独 XML 中定义的工具栏：
<?xml version="1.0" encoding="UTF-8"?>
<!-- LinearLayout that contains toolbar that is divided into 3 sections horizontally , layout_below="@+id/BarcodeScannerFrame-->
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/linearLayoutToolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:orientation="horizontal" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_left" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.68"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_center_toolbar" />
<ImageView
android:id="@+id/imageView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitXY"
android:src="@drawable/scanner_bottom_right_landscape_button" />
</LinearLayout>
onCreate,onResume,仅我活动的其他相关代码片段，LinearLayout 工具栏在运行时添加到线性或相对布局：
//import not included
public class ScanVinFromBarcodeActivity extends Activity {
// camera object that is used globally in this activity and also passed
// reference to PreviewSurface inner class
private Camera globalCamera;
private int cameraId = 0;
// bitmap that would created after picture is taken and converted from
// camera bytes
private Bitmap bmpOfTheImageFromCamera = null;
// global flag whether a camera has been detected
private boolean isThereACamera = false;
// layout for this activity
private LinearLayout RelativeLayoutBarcodeScanner= null;
// CameraPreview extends SurfaceView displays preview of images from the
// Camera
private CameraPreview newCameraPreview = null;
// used to inflate the xml layout
private SurfaceView surfaceViewBarcodeScanner = null;
private boolean cameraPreviewing = false;
// this continueToAutomaticallyDecode flag is initially set to TRUE, but
// will be set to FALSE on the first successful decode OR when a crucial
// method in the code process fails or throws an exception
private volatile boolean continueToAutomaticallyDecode = true;
// global flag used to indicate picture taking & decoding is in progress
private volatile boolean takingPictureAndDecodeInprogress = false;
// Bitmap options for bitmap creation from camera picture
BitmapFactory.Options options = null;
// used for samsung galaxy s devices only
private Matrix rotationMatrix90CounterClockWise = null;
// Reader is class from zxing used to decode barcodes
Reader reader = null;
// DecodeHintType hashtable is used to provide help to the zxing Reader
// class
Hashtable<DecodeHintType, Object> decodeHints = null;
//
private boolean onTouchEvent = true;
//
private OrientationEventListener orientationEventListener = null;
// 1 means the screen is PORTRAIT and 2 means screen is LANDSCAPE
private int latestScreenOrientation = 1;
//
Camera.Parameters Flash = null;
//
private String globalVIN = null;
//
private Handler handler = null;
//
private LinearLayout barcodeVinScannerToolbar = null;
public boolean isContinueToAutomaticallyDecode() {
return continueToAutomaticallyDecode;
}
public void setContinueToAutomaticallyDecode(
boolean continueToAutomaticallyDecode) {
this.continueToAutomaticallyDecode = continueToAutomaticallyDecode;
}
public boolean isTakingPictureAndDecodeInprogress() {
return takingPictureAndDecodeInprogress;
}
public void setTakingPictureAndDecodeInprogress(
boolean takingPictureAndDecodeInprogress) {
this.takingPictureAndDecodeInprogress = takingPictureAndDecodeInprogress;
}
/*
* This method , finds FEATURE_CAMERA, opens the camera, set parameters ,
* add CameraPreview to layout, set camera surface holder, start preview
*/
@SuppressLint("InlinedApi")
private void initializeGlobalCamera() {
try {
if (!getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
Toast.makeText(this, "No camera on this device",
Toast.LENGTH_LONG).show();
} else { // check for front camera ,and get the ID
cameraId = findFrontFacingCamera();
if (cameraId < 0) {
Toast.makeText(this, "No front facing camera found.",
Toast.LENGTH_LONG).show();
} else {
Log.d("ClassScanViewBarcodeActivity",
"camera was found , ID: " + cameraId);
// camera was found , set global camera flag to true
isThereACamera = true;
// OPEN
globalCamera = getGlobalCamera(cameraId);
// parameters auto focus
globalCamera.getParameters().setFocusMode(
Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
// set picture format to JPEG, everytime makesure JPEg
globalCamera.getParameters().setPictureFormat(
ImageFormat.JPEG);
autoFocusSetupForBarcode(globalCamera);
/*
* START early setup variables & setting used in
* jpegCallback in order to optimize the jpegCallback code
*/
options = new BitmapFactory.Options();
// option set for down sampling he captured image taken from
// the camera in order to MemoryOutOfBounds exception
options.inSampleSize = 4;
// image quality rather than speed in order to achieve early
// barcode detection & decode
options.inPreferQualityOverSpeed = false;
// Samsung galaxy S only , rotate to correct orientation
// ,and capture only the image within the guidance rectangle
rotationMatrix90CounterClockWise = new Matrix();
rotationMatrix90CounterClockWise.postRotate(90);
// early variable used by zxing to decode method
decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
decodeHints.put(DecodeHintType.PURE_BARCODE, Boolean.TRUE);
decodeHints.put(DecodeHintType.ASSUME_CODE_39_CHECK_DIGIT,
Boolean.TRUE);
reader = new MultiFormatReader();
turnOnFlashlight(globalCamera);
// pass surfaceView to CameraPreview
newCameraPreview = new CameraPreview(this, globalCamera) {
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.d("ClassScanViewBarcodeActivity",
" onTouchEvent(MotionEvent event) ");
onTouchEvent = true;
globalCamera
.autoFocus(autoFocusCallbackForAutomaticScan);
return super.onTouchEvent(event);
}
};
// pass CameraPreview to Layout
RelativeLayoutBarcodeScanner.addView(newCameraPreview);
// give reference SurfaceView to camera object
globalCamera.setPreviewDisplay(surfaceViewBarcodeScanner
.getHolder());
// PREVIEW
if (cameraPreviewing != true) {
globalCamera.startPreview();
}
Log.d("ClassScanViewBarcodeActivity",
"camera opened & previewing");
}
}// end else ,check for front camera
}// end try
catch (Exception exc) {
// in case of exception release resources & cleanup
if (globalCamera != null) {
globalCamera.stopPreview();
cameraPreviewing = false;
globalCamera.setPreviewCallback(null);
globalCamera.release();
globalCamera = null;
options = null;
rotationMatrix90CounterClockWise = null;
reader = null;
}
Log.d("ClassScanViewBarcodeActivity initializeGlobalCamera() exception:",
exc.getMessage());
exc.printStackTrace();
}// end catch
}// end ini
/* this method detect whether the camera flashlight a.k.a torch feature is available to be turned on then turns on the light*/
public void turnOnFlashlight(Camera camera) {
Log.d("ClassScanViewBarcodeActivity",
"turnOnFlashlight(Camera camera )");
boolean flag = false;
Context context = null;
if (camera != null) {
Log.d("ClassScanViewBarcodeActivity",
"turnOnFlashlight() , FEATURE_CAMERA_FLASH: " + flag);
context = RelativeLayoutBarcodeScanner.getContext();
if (context != null) {
flag = context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA_FLASH);
if (flag) {
Flash = camera.getParameters();
Flash.setFlashMode("torch");
camera.setParameters(Flash);
}// end if camera feature is available
else {
Log.d("ClassScanViewBarcodeActivity",
"turnOnFlashlight() , FEATURE_CAMERA_FLASH: "
+ flag);
}
}// end if context not null
}// end camera not null
}// end turnOnFlashlight(Camera camera )
// onCreate, instantiates layouts & surfaceView used for video preview
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_barcode_vin_scanner);
Log.d("ClassScanViewBarcodeActivity", "onCreate ");
// create surfaceView for previewing of camera image
RelativeLayoutBarcodeScanner = (LinearLayout) findViewById(R.id.LayoutForPreview);
surfaceViewBarcodeScanner = (SurfaceView) findViewById(R.id.surfaceViewBarcodeScanner);
barcodeVinScannerToolbar = (LinearLayout) findViewById(R.id.linearLayoutToolbar);
initializeGlobalCamera();
//*****TOOLBAR IS ADDED*****
if (RelativeLayoutBarcodeScanner!=null && barcodeVinScannerToolbar!=null)
{
//surfaceViewBarcodeScanner.addChildrenForAccessibility(list);
RelativeLayoutBarcodeScanner.addView(barcodeVinScannerToolbar);
}
// instantiate orientationEventListener
orientationEventListener = new OrientationEventListener(this,
SensorManager.SENSOR_DELAY_NORMAL) {
@Override
public void onOrientationChanged(int arg0) {
/*
latestScreenOrientation = ScreenUtility
.getScreenOrientation(RelativeLayoutBarcodeScanner.getContext());
Log.d("ClassScanViewBarcodeActivity",
"latestScreenOrientation: " + latestScreenOrientation);
if (orientationEventListener.canDetectOrientation()) {
orientationEventListener.enable();
Log.d("ClassScanViewBarcodeActivity",
"enabled orientationEventListener: "
+ String.valueOf(orientationEventListener
.canDetectOrientation()));
} else {
Log.d("ClassScanViewBarcodeActivity",
"enabled orientationEventListener: "
+ String.valueOf(orientationEventListener
.canDetectOrientation()));
}
*/
}
};
handler = new Handler();
}// end onCreate
@Override
protected void onResume() {
Log.d("ClassScanViewBarcodeActivity, onResume() globalCamera:",
String.valueOf(globalCamera));
initializeGlobalCamera();
//*****TOOLBAR IS ADDED*****
if (RelativeLayoutBarcodeScanner!=null && barcodeVinScannerToolbar!=null)
{
//surfaceViewBarcodeScanner.addChildrenForAccessibility(list);
RelativeLayoutBarcodeScanner.addView(barcodeVinScannerToolbar);
}
if (orientationEventListener != null) {
orientationEventListener.enable();
}
super.onResume();
}
@Override
protected void onStop() {
if (globalCamera != null) {
globalCamera.stopPreview();
cameraPreviewing = false;
globalCamera.setPreviewCallback(null);
globalCamera.release();
globalCamera = null;
}
if (orientationEventListener != null) {
orientationEventListener.disable();
}
super.onStop();
}
@Override
protected void onPause() {
if (globalCamera != null) {
globalCamera.stopPreview();
cameraPreviewing = false;
globalCamera.setPreviewCallback(null);
globalCamera.release();
globalCamera = null;
options = null;
rotationMatrix90CounterClockWise = null;
reader = null;
}
if (orientationEventListener != null) {
orientationEventListener.disable();
}
super.onPause();
}// end onPause()
//other irrelevant code was not included
}//end activity
尝试 #3，结果，屏幕冻结，未报告特定错误或异常：
错误日志：
**如果 eclipse GUI 工具显示所需的外观，那为什么工具栏仍然丢失？？？我想在底部有工具栏，最好使用 RelativeLayout 没有任何崩溃或屏幕冻结。任何帮助将不胜感激。
我正在使用三星 Galaxy S3 进行测试。
谢谢。**
