在我的任务中，我必须通过单击按钮调用相机并拍照，并且必须保存并在同一屏幕中显示图像。我已经尝试过并在模拟器中取得成功。但它不适用于真实设备。得到一些错误。尝试了很多。但是无法找到问题所在。更多，它在9700模拟器中完美运行，并在9500中显示一些错误。
public class CameraScreen extends MainScreen implements FieldChangeListener
{
/** The camera's video controller */
private VideoControl _videoControl;
private Field _videoField;
private EncodingProperties[] _encodings;
private int _indexOfEncoding = 0;
private static String FILE_NAME = System.getProperty("fileconn.dir.photos")+"IMAGE"; //"file:///SDCard/" + "myphotos/" + "IMAGE";//
private static String EXTENSION = ".bmp";
private static int _counter;
int flag = 0;
BitmapField imageField = new BitmapField();
HorizontalFieldManager menuBar = new HorizontalFieldManager(Field.USE_ALL_WIDTH);
VerticalFieldManager main_vfm = new VerticalFieldManager();
VerticalFieldManager camera_vfm = new VerticalFieldManager();
VerticalFieldManager image_vfm = new VerticalFieldManager();
ButtonField bt = new ButtonField("Click",ButtonField.CONSUME_CLICK);
ButtonField front_bt = new ButtonField("Front",ButtonField.CONSUME_CLICK);
ButtonField back_bt = new ButtonField("Back",ButtonField.CONSUME_CLICK);
ButtonField side1_bt = new ButtonField("Side 1",ButtonField.CONSUME_CLICK);
ButtonField side2_bt = new ButtonField("Side 2",ButtonField.CONSUME_CLICK);
public CameraScreen()
{
setTitle("First Screen");
bt.setChangeListener(this);
front_bt.setChangeListener(this);
back_bt.setChangeListener(this);
side1_bt.setChangeListener(this);
side2_bt.setChangeListener(this);
image_vfm.add(menuBar);
menuBar.add(front_bt);
menuBar.add(back_bt);
menuBar.add(side1_bt);
menuBar.add(side2_bt);
image_vfm.add(bt);
try {
Bitmap image = Bitmap.createBitmapFromBytes( readFile(),0, -1, 5 );
imageField.setBitmap(image);
image_vfm.add(imageField);
} catch(Exception e) {
System.out.println(e.toString());
}
main_vfm.add(image_vfm);
add(main_vfm);
front_bt.setFocus();
// Initialize the camera object and video field
initializeCamera();
// Initialize the list of possible encodings
initializeEncodingList();
// If the field was constructed successfully, create the UI
if(_videoField != null)
{
createUI();
}
// If not, display an error message to the user
else
{
camera_vfm.add( new RichTextField( "Error connecting to camera." ) );
}
}
/**
* Takes a picture with the selected encoding settings
*/
public void takePicture()
{
try
{
// A null encoding indicates that the camera should
// use the default snapshot encoding.
String encoding = null;
if( _encodings != null )
{
// Use the user-selected encoding
encoding = _encodings[_indexOfEncoding].getFullEncoding();
}
// Retrieve the raw image from the VideoControl and
// create a screen to display the image to the user.
createImageScreen( _videoControl.getSnapshot( encoding ) );
}
catch(Exception e)
{
home.errorDialog("ERROR " + e.getClass() + ": " + e.getMessage());
}
}
/**
* Prevent the save dialog from being displayed
* @see net.rim.device.api.ui.container.MainScreen#onSavePrompt()
*/
protected boolean onSavePrompt()
{
return true;
}
/**
* Initializes the Player, VideoControl and VideoField
*/
private void initializeCamera()
{
try
{
// Create a player for the Blackberry's camera
Player player = Manager.createPlayer( "capture://video" );
// Set the player to the REALIZED state (see Player javadoc)
player.realize();
// Grab the video control and set it to the current display
_videoControl = (VideoControl)player.getControl( "VideoControl" );
if (_videoControl != null)
{
// Create the video field as a GUI primitive (as opposed to a
// direct video, which can only be used on platforms with
// LCDUI support.)
_videoField = (Field) _videoControl.initDisplayMode (VideoControl.USE_GUI_PRIMITIVE, "net.rim.device.api.ui.Field");
_videoControl.setDisplayFullScreen(true);
//_videoControl.setDisplaySize(50, 50);
_videoControl.setVisible(true);
}
// Set the player to the STARTED state (see Player javadoc)
player.start();
}
catch(Exception e)
{
home.errorDialog("ERROR " + e.getClass() + ": " + e.getMessage());
}
}
/**
* Initialize the list of encodings
*/
private void initializeEncodingList()
{
try
{
// Retrieve the list of valid encodings
String encodingString = System.getProperty("video.snapshot.encodings");
// Extract the properties as an array of word
String[] properties = StringUtilities.stringToKeywords(encodingString);
// The list of encodings
Vector encodingList = new Vector();
//Strings representing the four properties of an encoding as
//returned by System.getProperty().
String encoding = "encoding";
String width = "width";
String height = "height";
String quality = "quality";
EncodingProperties temp = null;
for(int i = 0; i < properties.length ; ++i)
{
if( properties[i].equals(encoding))
{
if(temp != null && temp.isComplete())
{
// Add a new encoding to the list if it has been
// properly set.
encodingList.addElement( temp );
}
temp = new EncodingProperties();
// Set the new encoding's format
++i;
temp.setFormat(properties[i]);
}
else if( properties[i].equals(width))
{
// Set the new encoding's width
++i;
temp.setWidth(properties[i]);
}
else if( properties[i].equals(height))
{
// Set the new encoding's height
++i;
temp.setHeight(properties[i]);
}
else if( properties[i].equals(quality))
{
// Set the new encoding's quality
++i;
temp.setQuality(properties[i]);
}
}
// If there is a leftover complete encoding, add it.
if(temp != null && temp.isComplete())
{
encodingList.addElement( temp );
}
// Convert the Vector to an array for later use
_encodings = new EncodingProperties[ encodingList.size() ];
encodingList.copyInto((Object[])_encodings);
}
catch (Exception e)
{
// Something is wrong, indicate that there are no encoding options
_encodings = null;
home.errorDialog(e.toString());
}
}
/**
* Adds the VideoField to the screen
*/
private void createUI()
{
// Add the video field to the screen
camera_vfm.add(_videoField);
}
/**
* Create a screen used to display a snapshot
* @param raw A byte array representing an image
*/
private void createImageScreen( byte[] raw )
{
main_vfm.replace(camera_vfm, image_vfm);
fieldChanged(raw);
Bitmap image1 = Bitmap.createBitmapFromBytes( readFile(),0, -1, 5 );
try{
if(flag == 1){
}
else{
image_vfm.delete(imageField);
}
imageField.setBitmap(image1);
image_vfm.add(imageField);
}
catch(Exception e){System.out.println(e.toString());}
}
private byte[] readFile() {
byte[] result = null;
FileConnection fconn = null;
try {
fconn = (FileConnection)Connector.open(FILE_NAME + "_front" + EXTENSION);
} catch (IOException e) {
System.out.print("Error opening file");
}
if (!fconn.exists()) {
//Dialog.inform("file not exist");
} else {
InputStream in = null;
ByteVector bytes = new ByteVector();
try {
in = fconn.openInputStream();
} catch (IOException e) {
System.out.print("Error opening input stream");
}
try {
int c = in.read();
while (-1 != c) {
bytes.addElement((byte) c);
c = in.read();
}
result = bytes.getArray();
} catch (IOException e) {
System.out.print("Error reading input stream");
}
try {
fconn.close();
} catch (IOException e) {
System.out.print("Error closing file");
}
}
return result;
}
public void fieldChanged( final byte[] _raw )
{
try
{
flag ++;
// Create the connection to a file that may or
// may not exist.
FileConnection file = (FileConnection)Connector.open(FILE_NAME + "_front" + EXTENSION);
// If the file exists, increment the counter until we find
// one that hasn't been created yet.
if (file.exists()) {
file.delete();
file.close();
file = (FileConnection) Connector.open(FILE_NAME + "_front" + EXTENSION);
}
//FileConnection file_temp = (FileConnection)Connector.open(FILE_NAME + "tempimg" + EXTENSION);
//file_temp.delete();
// We know the file doesn't exist yet, so create it
file.create();
// Write the image to the file
OutputStream out = file.openOutputStream();
out.write(_raw);
// Close the connections
//out.close();
file.close();
//Dialog.inform( "Saved to " + FILE_NAME + "_front" + EXTENSION );
}
catch(Exception e)
{
home.errorDialog("ERROR " + e.getClass() + ": " + e.getMessage());
Dialog.inform( "File not saved this time");
}
}
/**
* Sets the index of the encoding in the 'encodingList' Vector
* @param index The index of the encoding in the 'encodingList' Vector
*/
public void setIndexOfEncoding(int index)
{
_indexOfEncoding = index;
}
/**
* @see net.rim.device.api.ui.Screen#invokeAction(int)
*/
protected boolean invokeAction(int action)
{
boolean handled = super.invokeAction(action);
if(!handled)
{
switch(action)
{
case ACTION_INVOKE: // Trackball click
{
takePicture();
return true;
}
}
}
return handled;
}
public void fieldChanged(Field field, int context) {
// TODO Auto-generated method stub
srn2 screen2 = new srn2();
srn3 screen3 = new srn3();
srn4 screen4 = new srn4();
if(field==bt)
{
main_vfm.replace(image_vfm, camera_vfm);
}
if(field==back_bt)
{
UiApplication.getUiApplication().popScreen(UiApplication.getUiApplication().getActiveScreen());
UiApplication.getUiApplication().pushScreen(screen2);
}
if(field==side1_bt)
{
UiApplication.getUiApplication().popScreen(UiApplication.getUiApplication().getActiveScreen());
UiApplication.getUiApplication().pushScreen(screen3);
}
if(field==side2_bt)
{
UiApplication.getUiApplication().popScreen(UiApplication.getUiApplication().getActiveScreen());
UiApplication.getUiApplication().pushScreen(screen4);
}
}
}
注意：此错误首先显示“javax.microedition.media.MediaException：已有另一个活动播放器。在现有播放器上调用Player.close（）以释放资源。”和相机打开，当我尝试拍照时，此错误显示“Error Class Java.lang.ArrayIndexOutOfBoundsException：Index 0＆gt; = 0”
答案 0 :(得分：0)
在调用_videoControl.getSnapshot( encoding )后，您需要关闭播放器（即拨打player.close()。这正是异常所说的内容。
然而，这种拍摄图像的方法非常不可靠 - 您无法将其用于每个BB设备模型。我不知道为什么RIM会把它放在SDK样本中。通过这样做，RIM以错误的方式推动开发人员。由于alishaik786提到在BB上拍摄图像的正确方法是使用Invoke.invokeApplication(Invoke.APP_TYPE_CAMERA, new CameraArguments())并FileSystemJournalListener实现。只需在这些上搜索StackOverflow以获取实现细节。我模糊地回忆起实现是痛苦的（就像BB上的许多其他部分一样），但一旦完成它就可以在任何设备上运行。
答案 1 :(得分：0)
你有两个错误
1."javax.microedition.media.MediaException: There is already another active Player. Call Player.close()
如果您尝试打开相机（播放器）而另一个相机实例已打开，则抛出此异常。在您的代码中，您需要将播放器对象定义为类级别，并且必须在拍摄快照后关闭播放器（如果您从一个屏幕推送到另一个屏幕，还需要关闭播放器）。
2."Error Class Java.lang.ArrayIndexOutOfBoundsException: Index 0>=0"
当编码数组大小为零时访问编码数组时，可能会发生此错误。 您可以使用_videoControl.getSnapshot（null）来确保此问题，该快照以默认编码方式拍摄。
首先确保这些问题并回复我。