我创建了一个自定义相机应用程序，它在几乎所有设备上都能正常工作，但它似乎在开发人员门户中列为其他设备的设备上崩溃。这些用户都给我不好的评价我想解决这个问题，但我很难弄清楚，因为它在我拥有的所有设备上都能完美运行。
camera.setPreviewDisplay(holder);是导致错误的原因，它在应用程序启动时发生。`
public class CamPreview extends SurfaceView implements SurfaceHolder.Callback
{
SurfaceHolder holder;
Camera camera;
private List<Camera.Size> sizes;
public CamPreview(Context context, Camera camera)
{
super(context);
this.camera = camera;
holder = this.getHolder();
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
holder.addCallback(this);
}
private Camera.Size getBestPreviewSize(int width, int height)
{
Camera.Size result=null;
Camera.Parameters p = camera.getParameters();
for (Camera.Size size : p.getSupportedPreviewSizes()) {
if (size.width<=width && size.height<=height) {
if (result==null) {
result=size;
} else {
int resultArea=result.width*result.height;
int newArea=size.width*size.height;
if (newArea>resultArea) {
result=size;
}
}
}
}
return result;
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height)
{
if (holder.getSurface() == null) return;
Camera.Parameters parameters = camera.getParameters();
sizes = parameters.getSupportedPreviewSizes();
Camera.Size optimalSize = getBestPreviewSize(width, height);
try{
parameters.setPreviewSize(optimalSize.width,optimalSize.height);
camera.setParameters(parameters);
}
catch (NullPointerException a)
{
}
camera.startPreview();
}
@Override
public void surfaceCreated(SurfaceHolder holder)
{
try
{
camera.setPreviewDisplay(holder);
}
catch (IOException e)
{
camera.release();
camera=null;
Log.d("FrontCam", "Error creating surface: " + e.getMessage());
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder)
{
if (camera != null) {
camera.stopPreview();
camera.setPreviewCallback(null);
camera.release();
}
}
}
日志猫：
java.lang.NullPointerException
at com.me.frontcam.CamPreview.surfaceCreated(CamPreview.java:136)
at android.view.SurfaceView.updateWindow(SurfaceView.java:552)
at android.view.SurfaceView.dispatchDraw(SurfaceView.java:350)
at android.view.ViewGroup.drawChild(ViewGroup.java:1644)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.ViewGroup.drawChild(ViewGroup.java:1644)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.ViewGroup.drawChild(ViewGroup.java:1644)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.View.draw(View.java:6883)
at android.widget.FrameLayout.draw(FrameLayout.java:357)
at android.view.ViewGroup.drawChild(ViewGroup.java:1646)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.View.draw(View.java:6883)
at android.widget.FrameLayout.draw(FrameLayout.java:357)
at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:1921)
at android.view.ViewRoot.draw(ViewRoot.java:1528)
at android.view.ViewRoot.performTraversals(ViewRoot.java:1264)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1866)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3687)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
at dalvik.system.NativeStart.main(Native Method)
我如何打开相机
void initCamera()
{
//check for front camera
if(Camera.getNumberOfCameras()>1)
{
camera= Camera.open(1);
try
{
camera.cancelAutoFocus();
}
catch (RuntimeException a)
{
}
try{
camera.setDisplayOrientation(90);
}
catch (NullPointerException a)
{
camera.setDisplayOrientation(90);
}
}
else
{
new AlertDialog.Builder(this)
.setTitle("Sorry but you cant use this app")
.setMessage("You do not have a front camera")
.setPositiveButton("Quit", new DialogInterface.OnClickListener() {
//Quits application
public void onClick(DialogInterface dialog, int which) {
finish();
}
})
.show();
}
}
然后我调用调用 CamPreview 构造函数的 initUI 方法
void initUI()
{
white= new ImageView(this);
imgShoot = (ImageButton) findViewById(R.id.imgShoot);
imgShoot.setOnClickListener(imgShootOnClick);
frmPreview = (FrameLayout) findViewById(R.id.frmPreview);
preview = new CamPreview(this, camera);
frmPreview.addView(white);
white.setImageResource(R.drawable.aperture_opening);
frmPreview.addView(preview);
frmPreview.bringChildToFront(preview);
}
我看了这两个，他们没有解决我的问题 Android - cam.setPreviewDisplay(holder) 运行到 IOError
.setPreviewDisplay(holder) 抛出空指针异常
任何帮助都非常感谢！