编辑：添加了适配器代码 编辑：我更新了我的主项目代码及其logcat
我有这个类似商店的应用程序并显示要选择的衣服。每件衣服都有一个按钮，我希望该按钮重定向到自定义相机，但每次打开我的应用程序时，它只会打开启动器活动并在之后崩溃，并且永远不会到达主要活动。
这些是我的按钮代码作为主要活动。
CLARTIPS_Home.java
public class CLARTIPS_Home extends AppCompatActivity {
private ListView lvProduct;
private ListProductAdapter adapter;
private List<Product> mProductList;
private DatabaseHelper mDBHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_clartips__home);
lvProduct = (ListView) findViewById(R.id.listview_product);
mDBHelper = new DatabaseHelper(this);
Button tryMe = (Button) findViewById(R.id.tryMe);
tryMe.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
openCam();
}
});
//Check exists database
File database = getApplicationContext().getDatabasePath(DatabaseHelper.DBNAME);
if(false==database.exists()) {
mDBHelper.getReadableDatabase();
//Copy db
if (copyDatabase(this)) {
Toast.makeText(this, "Success Copying Database", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Error Copying Database", Toast.LENGTH_SHORT).show();
return;
}
}
//Get product list in db when db exists
mProductList = mDBHelper.getListProduct();
//Init adapter
adapter = new ListProductAdapter(this,mProductList);
//Set adapter for listview
lvProduct.setAdapter(adapter);
}
private void openCam() {
Intent cameraIntent = new Intent(CLARTIPS_Home.this, Camera.class);
startActivity(cameraIntent);
}
private boolean copyDatabase(Context context) {
try {
InputStream inputStream = context.getAssets().open(DatabaseHelper.DBNAME);
String outFileName = DatabaseHelper.DBLOCATION + DatabaseHelper.DBNAME;
OutputStream outputStream = new FileOutputStream(outFileName);
byte[]buff = new byte[1024];
int length = 0;
while ((length = inputStream.read(buff)) > 0) {
outputStream.write(buff, 0, length);
}
outputStream.flush();
outputStream.close();
Log.w("MainActivity","DB copied");
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected (MenuItem item){
switch (item.getItemId()) {
case R.id.about:
Intent aboutIntent = new Intent(CLARTIPS_Home.this, About.class);
startActivity(aboutIntent);
}
return super.onOptionsItemSelected(item);
}
}
这些是我的相机代码。顺便说一下，我使用了Camera2。
Camera.java
public class Camera extends AppCompatActivity {
private Button btnCapture;
private TextureView textureView;
//Check state orientation of output image
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
static {
ORIENTATIONS.append(Surface.ROTATION_0, 90);
ORIENTATIONS.append(Surface.ROTATION_90, 0);
ORIENTATIONS.append(Surface.ROTATION_180, 270);
ORIENTATIONS.append(Surface.ROTATION_270, 180);
}
private String cameraId;
private CameraDevice cameraDevice;
private CameraCaptureSession cameraCaptureSessions;
private CaptureRequest.Builder captureRequestBuilder;
private android.util.Size imageDimension;
private ImageReader imageReader;
//Save to FILE
private File file;
private static final int REQUEST_CAMERA_PERMISSION = 200;
private boolean mFlashSupported;
private Handler mBackgroundHandler;
private HandlerThread mBackgroundThread;
CameraDevice.StateCallback stateCallBack = new CameraDevice.StateCallback(){
@Override
public void onOpened(@NonNull CameraDevice camera) {
cameraDevice = camera;
createCameraPreview();
}
@Override
public void onDisconnected(@NonNull CameraDevice cameraDevice) {
cameraDevice.close();
}
@Override
public void onError(@NonNull CameraDevice cameraDevice, int i) {
cameraDevice.close();
cameraDevice=null;
}
};
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.show_camera);
textureView = (TextureView)findViewById(R.id.textureView);
//to check if expression is true or false
assert textureView != null;
textureView.setSurfaceTextureListener(textureListener);
btnCapture = (Button)findViewById(R.id.btnCapture);
btnCapture.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
takePicture();
}
});
}
private void takePicture() {
if(cameraDevice == null)
return;
CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
try{
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());
android.util.Size[] jpegSizes = null;
if(characteristics != null)
jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputSizes(ImageFormat.JPEG);
//Capture image with custom size
int width = 640;
int height = 480;
if(jpegSizes != null && jpegSizes.length > 0){
width = jpegSizes[0].getWidth();
height = jpegSizes[0].getHeight();
}
final ImageReader reader = ImageReader.newInstance(width,height,ImageFormat.JPEG,1);
List<Surface> outputSurface = new ArrayList<>(2);
outputSurface.add(reader.getSurface());
outputSurface.add(new Surface(textureView.getSurfaceTexture()));
final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
captureBuilder.addTarget(reader.getSurface());
captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
//Check orientation base on device
int rotation = getWindowManager().getDefaultDisplay().getRotation();
captureBuilder.set(CaptureRequest.JPEG_ORIENTATION,ORIENTATIONS.get(rotation));
file = new File(Environment.getExternalStorageDirectory()+"/"+UUID.randomUUID().toString()+".jpg");
ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener(){
@Override
public void onImageAvailable(ImageReader imageReader) {
Image image = null;
try{
image = reader.acquireLatestImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] bytes = new byte[buffer.capacity()];
buffer.get(bytes);
save(bytes);
}
catch (FileNotFoundException e){
e.printStackTrace();
}
catch (IOException e){
e.printStackTrace();
}
finally {
{
if (image != null)
image.close();
}
}
}
private void save(byte[] bytes) throws IOException {
OutputStream outputSteam = null;
try{
outputSteam = new FileOutputStream(file);
outputSteam.write(bytes);
}finally {
if(outputSteam != null)
outputSteam.close();
}
}
};
reader.setOnImageAvailableListener(readerListener,mBackgroundHandler);
final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
Toast.makeText(Camera.this, "Saved "+file, Toast.LENGTH_SHORT).show();
createCameraPreview();
}
};
cameraDevice.createCaptureSession(outputSurface, new CameraCaptureSession.StateCallback(){
@Override
public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
try{
cameraCaptureSession.capture(captureBuilder.build(),captureListener,mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
}
},mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void createCameraPreview() {
try{
SurfaceTexture texture = textureView.getSurfaceTexture();
assert texture != null;
texture.setDefaultBufferSize(imageDimension.getWidth(),imageDimension.getHeight());
Surface surface = new Surface(texture);
captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
captureRequestBuilder.addTarget(surface);
cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
if(cameraDevice == null)
return;
cameraCaptureSessions = cameraCaptureSession;
updatePreview();
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
Toast.makeText(Camera.this, "Changed", Toast.LENGTH_SHORT).show();
}
}, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void updatePreview() {
if(cameraDevice == null)
Toast.makeText(this, "Error", Toast.LENGTH_SHORT).show();
captureRequestBuilder.set(CaptureRequest.CONTROL_MODE,CaptureRequest.CONTROL_MODE_AUTO);
try{
cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(), null,mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void openCamera() {
CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
try{
cameraId = manager.getCameraIdList()[0];
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
assert map != null;
imageDimension = map.getOutputSizes(SurfaceTexture.class)[0];
//Check realtime permission if run higher API 23
if(ActivityCompat.checkSelfPermission(this, android.Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(this,new String[]{
android.Manifest.permission.CAMERA,
android.Manifest.permission.WRITE_EXTERNAL_STORAGE
},REQUEST_CAMERA_PERMISSION);
return;
}
manager.openCamera(cameraId,stateCallBack,null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
TextureView.SurfaceTextureListener textureListener = new TextureView.SurfaceTextureListener(){
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
openCamera();
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int i, int i1) {
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
return false;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {
}
};
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if(requestCode == REQUEST_CAMERA_PERMISSION){
if(grantResults[0] != PackageManager.PERMISSION_GRANTED){
Toast.makeText(this, "You can't use camera without permission", Toast.LENGTH_SHORT).show();
finish();
}
}
}
@Override
protected void onResume() {
super.onResume();
startBackgroundThread();
if(textureView.isAvailable())
openCamera();
else
textureView.setSurfaceTextureListener(textureListener);
}
@Override
protected void onPause() {
stopBackgroundThread();
super.onPause();
}
private void stopBackgroundThread() {
mBackgroundThread.quitSafely();
try{
mBackgroundThread.join();
mBackgroundThread = null;
mBackgroundHandler = null;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private void startBackgroundThread() {
mBackgroundThread = new HandlerThread("Camera Background");
mBackgroundThread.start();
mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
}
}
我上大学的最后一年就在这里。所有你的答案将非常感谢。非常感谢你。
logcat的
02-13 08:11:13.608 20959-20959/? I/art: Late-enabling -Xcheck:jni
02-13 08:11:13.804 20959-20959/? W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
02-13 08:11:13.953 20959-20959/? I/ViewRootImpl: CPU Rendering VSync enable = true
02-13 08:11:13.962 20959-21000/? D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
02-13 08:11:14.032 20959-20959/? D/Atlas: Validating map...
02-13 08:11:14.055 20959-20959/? V/PhoneWindow: updateColorViewInt()if drawable=null color=ff000000
02-13 08:11:14.096 20959-21000/? I/Adreno-EGL: <qeglDrvAPI_eglInitialize:379>: EGL 1.4 QUALCOMM build: Nondeterministic_AU_msm8916_32_LA.BR.1.2.4_RB1__release_AU (Ic8ede1fb34)
OpenGL ES Shader Compiler Version: E031.25.03.04
Build Date: 12/10/15 Thu
Local Branch: mybranch17178083
Remote Branch: quic/LA.BR.1.2.4_rb1.30
Local Patches: NONE
Reconstruct Branch: NOTHING
02-13 08:11:14.157 20959-21000/nerds.thesis.clartips I/OpenGLRenderer: Initialized EGL, version 1.4
02-13 08:11:14.478 20959-21000/nerds.thesis.clartips D/OpenGLRenderer: Enabling debug mode 0
02-13 08:11:14.627 20959-20959/nerds.thesis.clartips I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@2d38ca61 time:44076123
02-13 08:11:17.990 20959-20959/nerds.thesis.clartips I/Timeline: Timeline: Activity_launch_request id:nerds.thesis.clartips time:44079486
02-13 08:11:18.221 20959-20969/nerds.thesis.clartips W/art: Suspending all threads took: 10.057ms
02-13 08:11:18.230 20959-20959/nerds.thesis.clartips D/AndroidRuntime: Shutting down VM
02-13 08:11:18.232 20959-20959/nerds.thesis.clartips E/AndroidRuntime: FATAL EXCEPTION: main
Process: nerds.thesis.clartips, PID: 20959
java.lang.RuntimeException: Unable to start activity ComponentInfo{nerds.thesis.clartips/nerds.thesis.clartips.CLARTIPS_Home}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2335)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2397)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1310)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5270)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at nerds.thesis.clartips.CLARTIPS_Home.onCreate(CLARTIPS_Home.java:42)
at android.app.Activity.performCreate(Activity.java:6057)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2288
以下是我的适配器代码。
ListProductAdapter.java
public class ListProductAdapter extends BaseAdapter {
private Context mContext;
private List<Product> mProductList;
public ListProductAdapter(Context mContext, List<Product> mProductList) {
this.mContext = mContext;
this.mProductList = mProductList;
}
@Override
public int getCount() {
return mProductList.size();
}
@Override
public Object getItem(int position) {
return mProductList.get(position);
}
@Override
public long getItemId(int position) {
return mProductList.get(position).getId();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = View.inflate(mContext, R.layout.listview, null);
TextView pName = (TextView) v.findViewById(R.id.product_name);
ImageView pImage = (ImageView) v.findViewById(R.id.product_image);
TextView pPrice = (TextView) v.findViewById(R.id.product_price);
TextView pDescription = (TextView) v.findViewById(R.id.product_description);
TextView pCategory = (TextView) v.findViewById(R.id.product_category);
pName.setText(mProductList.get(position).getName());
Product image = mProductList.get(position);
byte[] img = image.getImage();
Bitmap bitmap = BitmapFactory.decodeByteArray(img, 0, img.length);
pImage.setImageBitmap(bitmap);
pPrice.setText("$" + String.valueOf(mProductList.get(position).getPrice()));
pDescription.setText(mProductList.get(position).getDescription());
pCategory.setText(mProductList.get(position).getCategory());
return v;
}
}
答案 0 :(得分：0)
您有ActivityNotFoundException个例外。这是因为Camera.java未在manifest.xml文件中注册为活动。试试这个，编辑manifest.xml，在<activity android:name=".Camera"/>开始和结束<application>标记内添加</application>，如下所示。
<application>
<!--<activity android:name=".OtherActivities"/> Declaration of other activities -->
<activity android:name=".Camera"/>
</application>
要摆脱nullpointer异常，请在适配器类中添加此类＆＃39; getView方法
Button tryMe = (Button) v.findViewById(R.id.tryMe);
tryMe.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent cameraIntent = new Intent(mContext, Camera.class);
mContext.startActivity(cameraIntent);
}
});
并从您的活动中删除与按钮相关的代码。