我在android中开发了一个Camera应用程序。它使用表面视图捕获图像。下面是我用来打开相机的代码
try {
// attempt to get a Front Camera instance
c = Camera.open(Camera.CameraInfo.CAMERA_FACING_FRONT);
} catch (Exception e) {
// TODO Auto-generated catch block
System.out
.println("fail to connect to Front Camera");
}
if (c == null) {
try {
// attempt to get a Back Camera instance
c = Camera.open(1);
} catch (Exception e) {
// TODO: handle exception
System.out
.println("fail to connect to Camera with id = 1");
}
}
if (c == null) {
try {
// attempt to get a Back Camera instance
c = Camera.open(0);
} catch (Exception e) {
// TODO: handle exception
System.out
.println("fail to connect to Camera with id = 0");
}
}
if (c == null) {
try {
// attempt to get a Back Camera instance
c = Camera.open();
} catch (Exception e) {
// TODO: handle exception
System.out
.println("fail to connect to Back Camera");
return c;
}
其中c是相机的对象。
除Nexus 7平板电脑外,其他手机也能正常使用。在Nexus 7中,代码在所有情况下抛出异常,除了最后一个,即c = Camera.open();
,但对象c
仍为null
。
这是堆栈跟踪
11-22 12:36:57.559 W/System.err(7621): java.lang.NullPointerException
11-22 12:36:57.559 W/System.err(7621): at
com.MyPackage.OpenCamera.getFrontCameraInstance(OpenCamera.java:238)
11-22 12:36:57.559 W/System.err(7621): at
com.MyPackage.OpenCamera.onCreate(OpenCamera.java:123)
11-22 12:36:57.559 W/System.err(7621): at
android.app.Activity.performCreate(Activity.java:5104)
11-22 12:36:57.559 W/System.err(7621): at
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
11-22 12:36:57.559 W/System.err(7621): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
11-22 12:36:57.559 W/System.err(7621): at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
11-22 12:36:57.559 W/System.err(7621): at
android.app.ActivityThread.access$600(ActivityThread.java:141)
11-22 12:36:57.559 W/System.err(7621): at android.app.ActivityThread
$H.handleMessage(ActivityThread.java:1234)
11-22 12:36:57.559 W/System.err(7621): at
android.os.Handler.dispatchMessage(Handler.java:99)
11-22 12:36:57.559 W/System.err(7621): at android.os.Looper.loop
(Looper.java:137)
11-22 12:36:57.559 W/System.err(7621): at android.app.ActivityThread.main
(ActivityThread.java:5039)
11-22 12:36:57.559 W/System.err(7621): at
java.lang.reflect.Method.invokeNative(Native Method)
11-22 12:36:57.559 W/System.err(7621): at java.lang.reflect.Method.invoke
(Method.java:511)
11-22 12:36:57.559 W/System.err(7621): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run
(ZygoteInit.java:793)
11-22 12:36:57.559 W/System.err(7621): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-22 12:36:57.559 W/System.err(7621): at dalvik.system.NativeStart.main
(Native Method)
11-22 12:36:57.559 I/System.out(7621): Error in setting Parameter
11-22 12:36:57.609 I/ActivityManager(480): Displayed
11-22 12:36:57.679 W/System.err(7621): at
android.location.Geocoder.getFromLocation(Geocoder.java:136)
11-22 12:36:57.679 W/System.err(7621): at com.MyPackage.OpenCamera.
$MyTimmer$1.run(OpenCamera.java:336)
11-22 12:36:57.679 W/System.err(7621): java.lang.NullPointerException
11-22 12:36:57.679 W/System.err(7621): at com.MyPackage.OpenCamera.
$MyTimmer$1.run(OpenCamera.java:344)
所以我不能用它来捕捉图像。 任何解决方案???
...谢谢
答案 0 :(得分:6)
在Nexus 7上使用以下代码时: int cameraId = CameraInfo.CAMERA_FACING_FRONT; 但是,如您所见,cameraId为1,使用1作为参数会导致错误。 我发现使用0代替1可以工作,但每次使用后必须释放相机,所以我继续调用Camera.open(cameraId).release(); 我意识到这很难看,但它似乎解决了Nexus 7的问题。
int cameraId = -1;
boolean errorFound = false;
boolean hasFeatCamera = getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA);
if (hasFeatCamera) {
try{
cameraId = CameraInfo.CAMERA_FACING_BACK;
Camera.open(cameraId).release();
}catch(Exception e){
Camera.open(0).release();
}
} else if(CameraInfo.CAMERA_FACING_FRONT>-1){
try{
cameraId = CameraInfo.CAMERA_FACING_FRONT;
Camera.open(cameraId).release();
}catch(Exception e){
errorFound = true;
}
if(errorFound){
try{
Camera.open(0).release(); // Put in for Nexus 7 as CameraInfo.CAMERA_FACING_FRONT= 1 but it only loads if the id is actually 0
cameraId = 0;
}catch(Exception e){
cameraId = -1;
}
}
}
if(cameraId<0){
Toast.makeText(this, "No camera found.",
Toast.LENGTH_LONG).show();
}
答案 1 :(得分:3)
有点晚了,但也许对某人有所帮助。 我有完全相同的问题,无法让Nexus 7相机与提供给getCamera(idx)的任何索引一起使用。
我从Playstore安装了一个相机“Kamera Nexus 7”应用程序。重置/更新后我没有任何相机应用程序。 这个应用程序工作,在我使用它一次后,我可以通过使用获得凸轮 Camera.getCamera(0);
所以也许这里的答案中没有涉及额外的“解锁要求”? (在安装应用程序之前,它们对我不起作用)