我的简单相机应用程序（android）赢得了'；t在第一次尝试后加载相机视图
我只是想制作一个使用运行时权限的简单相机应用程序……在第一次启动应用程序（请求相机权限）时，它似乎可以正常加载。在允许访问后，它工作了…但一旦我关闭它并再次启动它，它就会显示一个白色图像，带有我的图标，不会响应。我已经在应用程序中手动检查了权限，相机仍然被授予访问权限，但我想我把权限代码搞乱了 以下是主要活动代码：我的简单相机应用程序（android）赢得了'；t在第一次尝试后加载相机视图,android,camera,android-camera,runtime-permissions,Android,Camera,Android Camera,Runtime Permissions,我只是想制作一个使用运行时权限的简单相机应用程序……在第一次启动应用程序（请求相机权限）时，它似乎可以正常加载。在允许访问后，它工作了…但一旦我关闭它并再次启动它，它就会显示一个白色图像，带有我的图标，不会响应。我已经在应用程序中手动检查了权限，相机仍然被授予访问权限，但我想我把权限代码搞乱了 以下是主要活动代码： public class MainActivity extends AppCompatActivity { private static final int MY_PERM
public class MainActivity extends AppCompatActivity {
private static final int MY_PERMISSIONS_REQUEST_CAMERA = 1;
private Camera mCamera = null;
private Camera mCameraFront = null;
private CameraView mCameraView = null;
public int switchCamera = 1;
// int permissionCheck = ContextCompat.checkSelfPermission(this,
// Manifest.permission.CAMERA);
// String[] perms = {"android.permission.CAMERA"};
// int permsRequestCode = 200;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.CAMERA)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.CAMERA},
MY_PERMISSIONS_REQUEST_CAMERA);
try {
mCamera = Camera.open(1);//you can use open(int) to use different cameras
} catch (Exception e) {
Log.d("ERROR", "Failed to get camera: " + e.getMessage());
}
SwapCamera();
// if (mCamera != null) {
//// mCameraView = new CameraView(this, mCamera);//create a SurfaceView to show camera data
//// FrameLayout camera_view = (FrameLayout)findViewById(R.id.camera_view);
//// camera_view.addView(mCameraView);//add the SurfaceView to the layout
// SwapCamera();
// }
//btn to close the application
ImageButton imgClose = (ImageButton) findViewById(R.id.imgClose);
imgClose.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mCamera.setPreviewCallback(null);
mCamera.setErrorCallback(null);
mCamera.stopPreview();
mCamera.release();
mCamera = null;
System.exit(0);
}
});
// btn to switch camera
ImageButton imgSwitch = (ImageButton) findViewById(R.id.cameraSwitch);
imgSwitch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// switchCamera++;
}
});
}
}
}
public void SwapCamera() {
mCameraView = new CameraView(this, mCamera);//create a SurfaceView to show camera data
FrameLayout camera_view = (FrameLayout)findViewById(R.id.camera_view);
camera_view.addView(mCameraView);//add the SurfaceView to the layout
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_CAMERA: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted, yay! Do the
// camera-related task you need to do.
try{
mCamera = Camera.open(1);//you can use open(int) to use different cameras
} catch (Exception e){
Log.d("ERROR", "Failed to get camera: " + e.getMessage());
}
if(mCamera != null) {
// mCameraView = new CameraView(this, mCamera);//create a SurfaceView to show camera data
// FrameLayout camera_view = (FrameLayout)findViewById(R.id.camera_view);
// camera_view.addView(mCameraView);//add the SurfaceView to the layout
SwapCamera();
}
//btn to close the application
ImageButton imgClose = (ImageButton)findViewById(R.id.imgClose);
imgClose.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mCamera.setPreviewCallback(null);
mCamera.setErrorCallback(null);
mCamera.stopPreview();
mCamera.release();
mCamera = null;
System.exit(0);
}
});
// btn to switch camera
ImageButton imgSwitch = (ImageButton)findViewById(R.id.cameraSwitch);
imgSwitch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// switchCamera++;
}
});
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
}
return;
}
// other 'case' lines to check for other
// permissions this app might request
}
}
public void onActivityResult() {
}
}
您只能在ActivityResult的
中启动camera staff，只有在您没有权限时才会调用它，并请求它们：
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
...
}
对于已授予权限的情况，此if
需要else
。您必须在这里执行与在活动结果中执行的相同的操作：
else {
try{
mCamera = Camera.open(1);//you can use open(int) to use different cameras
} catch (Exception e){
Log.d("ERROR", "Failed to get camera: " + e.getMessage());
}
if(mCamera != null) {
// mCameraView = new CameraView(this, mCamera);//create a SurfaceView to show camera data
// FrameLayout camera_view = (FrameLayout)findViewById(R.id.camera_view);
// camera_view.addView(mCameraView);//add the SurfaceView to the layout
SwapCamera();
}
//btn to close the application
ImageButton imgClose = (ImageButton)findViewById(R.id.imgClose);
imgClose.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mCamera = null;
System.exit(0);
}
});
// btn to switch camera
ImageButton imgSwitch = (ImageButton)findViewById(R.id.cameraSwitch);
imgSwitch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// switchCamera++;
}
});
}
您只能在ActivityResult的中启动camera staff，只有在您没有权限时才会调用它，并请求它们：
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
...
}
对于已授予权限的情况，此if
需要else
。您必须在这里执行与在活动结果中执行的相同的操作：
else {
try{
mCamera = Camera.open(1);//you can use open(int) to use different cameras
} catch (Exception e){
Log.d("ERROR", "Failed to get camera: " + e.getMessage());
}
if(mCamera != null) {
// mCameraView = new CameraView(this, mCamera);//create a SurfaceView to show camera data
// FrameLayout camera_view = (FrameLayout)findViewById(R.id.camera_view);
// camera_view.addView(mCameraView);//add the SurfaceView to the layout
SwapCamera();
}
//btn to close the application
ImageButton imgClose = (ImageButton)findViewById(R.id.imgClose);
imgClose.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mCamera = null;
System.exit(0);
}
});
// btn to switch camera
ImageButton imgSwitch = (ImageButton)findViewById(R.id.cameraSwitch);
imgSwitch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// switchCamera++;
}
});
}
我不知道我在哪里缺少了“else”…我有onRequestPermissionsResult方法的“try”块…我应该把它移到onCreate方法吗？（在“if（ContextCompat.checkSelfPermission（this，Manifest.permission.CAMERA）！=PackageManager.permission_grated）”区域内）应将其复制到onCreate方法@Vlad Matvienko解释道。我很困惑我在哪里遗漏了“else”…我有onRequestPermissionsResult方法的“try”块…我应该将它移到onCreate方法吗？（在“if（ContextCompat.checkSelfPermission（this，Manifest.permission.CAMERA）！=PackageManager.permission_grated）”区域内）应将其复制到onCreate方法@Vlad Matvienko解释说，我已经将try块复制到else语句中（仅超出了！=授予的权限），但我仍然得到相同的结果…我想我误解了你的意思answer@fmi，你有什么例外吗？没有…我第一次加载应用时，它会提示我请求…前向摄像头会显示两个图标，直到…关闭应用程序并重新打开后，我不再得到提示，我只看到一个白色屏幕，上面有两个图标，对触摸不再有反应。你可以更新你问题中的代码让我看看，也许我发现了什么。我刚刚更新了代码，但我注意到我收到了一条警告…我的“addView”调用“可能会产生空指针异常”…这是在我的swapCamera（）方法中。我已将try块复制到else语句中（仅超出授予的！=权限），但仍然得到相同的结果…我想我误解了您的answer@fmi，你有什么例外吗？没有…我第一次加载应用时，它会提示我请求…前向摄像头会显示两个图标，直到…关闭应用程序并重新打开后，我不再得到提示，我只看到一个白色屏幕，上面有两个图标，对触摸不再有反应。你可以更新你问题中的代码让我看看，也许我发现了什么。我刚刚更新了代码，但我注意到我收到了一条警告…我的“addView”调用“可能会产生空指针异常”…它在我的swapCamera（）方法中