Android: "declarative-camera" project show black screen

I got a black screen when run declarative-camera on my android device.
but if i witch to video and record, i can view the record fine...
here is console output:

Starting remote process.D/dalvikvm( 7357): Late-enabling CheckJNI
D/dalvikvm( 7357): Trying to load lib /data/data/com.lbe.security.miui/app_hips/liblbeclient.so 0x420a3b60
D/dalvikvm( 7357): Added shared lib /data/data/com.lbe.security.miui/app_hips/liblbeclient.so 0x420a3b60
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libgnustl_shared.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libgnustl_shared.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libgnustl_shared.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Core.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Core.so 0x420d8030
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Network.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Network.so 0x420d8030
I/Qt ( 7357): Network start
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Qml.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Qml.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libQt5Qml.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Gui.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Gui.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libQt5Gui.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Quick.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Quick.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libQt5Quick.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5QuickParticles.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5QuickParticles.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libQt5QuickParticles.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Multimedia.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Multimedia.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libQt5Multimedia.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5MultimediaQuick_p.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5MultimediaQuick_p.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libQt5MultimediaQuick_p.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Widgets.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5Widgets.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libQt5Widgets.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5AndroidExtras.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5AndroidExtras.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/data/org.qtproject.example.declarative_camera/lib/libQt5AndroidExtras.so 0x420d8030, skipping init
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/qt-reserved-files/plugins/platforms/android/libqtforandroid.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/qt-reserved-files/plugins/platforms/android/libqtforandroid.so 0x420d8030
I/Qt ( 7357): qt start
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5QuickParticles.so 0x420d8030
D/dalvikvm( 7357): Shared lib '/data/data/org.qtproject.example.declarative_camera/lib/libQt5QuickParticles.so' already loaded in same CL 0x420d8030
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/qt-reserved-files/plugins/mediaservice/libqtmedia_android.so 0x420d8030
D/dalvikvm( 7357): Added shared lib /data/data/org.qtproject.example.declarative_camera/qt-reserved-files/plugins/mediaservice/libqtmedia_android.so 0x420d8030
D/dalvikvm( 7357): Trying to load lib /data/data/org.qtproject.example.declarative_camera/lib/libQt5MultimediaQuick_p.so 0x420d8030
D/dalvikvm( 7357): Shared lib '/data/data/org.qtproject.example.declarative_camera/lib/libQt5MultimediaQuick_p.so' already loaded in same CL 0x420d8030
D/dalvikvm( 7357): Trying to load lib /data/app-lib/org.qtproject.example.declarative_camera-1/libdeclarative-camera.so 0x420d8030
D/Qt ( 7357): qml/qqmlengine.cpp:1454 (QQmlDebuggingEnabler::QQmlDebuggingEnabler(bool)): QML debugging is enabled. Only use this in a safe environment.
D/dalvikvm( 7357): Added shared lib /data/app-lib/org.qtproject.example.declarative_camera-1/libdeclarative-camera.so 0x420d8030
D/dalvikvm( 7357): No JNI_OnLoad found in /data/app-lib/org.qtproject.example.declarative_camera-1/libdeclarative-camera.so 0x420d8030, skipping init
I/Adreno-EGL( 7357): <qeglDrvAPI_eglInitialize:410>: EGL 1.4 QUALCOMM build: AU_LINUX_ANDROID_LNX.LA.3.5.2.2.1_RB1.04.04.02.090.019_msm8974_LNX.LA.3.5.2.2.1_RB1__release_AU ()
I/Adreno-EGL( 7357): OpenGL ES Shader Compiler Version: E031.24.00.15
I/Adreno-EGL( 7357): Build Date: 06/11/14 Wed
I/Adreno-EGL( 7357): Local Branch:
I/Adreno-EGL( 7357): Remote Branch: quic/LNX.LA.3.5.2.2.1_rb1
I/Adreno-EGL( 7357): Local Patches: NONE
I/Adreno-EGL( 7357): Reconstruct Branch: AU_LINUX_ANDROID_LNX.LA.3.5.2.2.1_RB1.04.04.02.090.019 + NOTHING
D/OpenGLRenderer( 7357): Enabling debug mode 0
I/Timeline( 7357): Timeline: Activity_idle id: android.os.BinderProxy@420d36e0 time:226399395
D/Qt ( 7357): fontdatabases/basic/qbasicfontdatabase.cpp:239 (static QStringList QBasicFontDatabase::addTTFile(const QByteArray&, const QByteArray&, QSupportedWritingSystems*)): FT_New_Face failed with index 0 : 90
D/dalvikvm( 7357): GC_FOR_ALLOC freed 1979K, 20% free 14717K/18188K, paused 19ms, total 19ms
E/ExtMediaPlayer-JNI( 7357): QCMediaPlayer could not be located....
E/MediaPlayer-JNI( 7357): QCMediaPlayer mediaplayer NOT present
E/MediaPlayer( 7357): Should have subtitle controller already set
W/BufferQueue( 7357): [unnamed-7357-1] cancelBuffer: BufferQueue has been abandoned!
W/BufferQueue( 7357): [unnamed-7357-1] cancelBuffer: BufferQueue has been abandoned!
W/BufferQueue( 7357): [unnamed-7357-1] cancelBuffer: BufferQueue has been abandoned!
W/BufferQueue( 7357): [unnamed-7357-1] cancelBuffer: BufferQueue has been abandoned!
W/BufferQueue( 7357): [unnamed-7357-1] cancelBuffer: BufferQueue has been abandoned!
D/Camera ( 7357): app passed NULL surface