【发布时间】：2015-02-21 10:09:22
【问题描述】：
我试过了
private Camera openFrontFacingCamera() {
Camera camera = null;
// Look for front-facing camera, using the Gingerbread API.
// Java reflection is used for backwards compatibility with pre-Gingerbread APIs.
try {
Class<?> cameraClass = Class.forName("android.hardware.Camera");
Object cameraInfo = null;
Field field = null;
int cameraCount = 0;
Method getNumberOfCamerasMethod = cameraClass.getMethod( "getNumberOfCameras" );
if ( getNumberOfCamerasMethod != null ) {
cameraCount = (Integer) getNumberOfCamerasMethod.invoke( null, (Object[]) null );
}
Class<?> cameraInfoClass = Class.forName("android.hardware.Camera$CameraInfo");
if ( cameraInfoClass != null ) {
cameraInfo = cameraInfoClass.newInstance();
}
if ( cameraInfo != null ) {
field = cameraInfo.getClass().getField( "facing" );
}
Method getCameraInfoMethod = cameraClass.getMethod( "getCameraInfo", Integer.TYPE, cameraInfoClass );
if ( getCameraInfoMethod != null && cameraInfoClass != null && field != null ) {
for ( int camIdx = 0; camIdx < cameraCount; camIdx++ ) {
getCameraInfoMethod.invoke( null, camIdx, cameraInfo );
int facing = field.getInt( cameraInfo );
if ( facing == 1 ) { // Camera.CameraInfo.CAMERA_FACING_FRONT
try {
Method cameraOpenMethod = cameraClass.getMethod( "open", Integer.TYPE );
if ( cameraOpenMethod != null ) {
camera = (Camera) cameraOpenMethod.invoke( null, camIdx );
}
} catch (RuntimeException e) {
Log.e(TAG, "Camera failed to open: " + e.getLocalizedMessage());
}
}
}
}
}
// Ignore the bevy of checked exceptions the Java Reflection API throws - if it fails, who cares.
catch ( ClassNotFoundException e ) {Log.e(TAG, "ClassNotFoundException" + e.getLocalizedMessage());}
catch ( NoSuchMethodException e ) {Log.e(TAG, "NoSuchMethodException" + e.getLocalizedMessage());}
catch ( NoSuchFieldException e ) {Log.e(TAG, "NoSuchFieldException" + e.getLocalizedMessage());}
catch ( IllegalAccessException e ) {Log.e(TAG, "IllegalAccessException" + e.getLocalizedMessage());}
catch ( InvocationTargetException e ) {Log.e(TAG, "InvocationTargetException" + e.getLocalizedMessage());}
catch ( InstantiationException e ) {Log.e(TAG, "InstantiationException" + e.getLocalizedMessage());}
catch ( SecurityException e ) {Log.e(TAG, "SecurityException" + e.getLocalizedMessage());}
if ( camera == null ) {
// Try using the pre-Gingerbread APIs to open the camera.
try {
camera = Camera.open();
} catch (RuntimeException e) {
Log.e(TAG, "Camera failed to open: " + e.getLocalizedMessage());
}
}
return camera;
}
但它只显示空白屏幕PLz帮助
【问题讨论】：
-
我认为您可以使用相机类中的以下 api 在 ID 的帮助下打开您想要的任何相机：public static Camera open (int cameraId) -- 在 API 级别 9 中引入，即 Gingerbread。通常 cameraIds 将是，0 用于后置摄像头，1 用于前置摄像头。但是您仍然可以像上面那样验证 cameraIds。
-
哪个 API？你指定了
-
假设cameraID 1代表前置摄像头，然后这样调用：Camera frontCam = Camera.open(1);