android - ImageView 在 Camera Surface View 后面移动

Question

我试图将 ImageView 放置在相机表面 View 上，当应用程序启动时， ImageView 位于相机预览之上，但在拍摄照片并将其设置为 ImageView 后，相机预览嵌套在移动中的 RelativeLayout当调用 startpreview 再次启动相机时向前，因此相机预览最终位于 imageview 之上。在 xml 布局中的 imageview 之后放置了相同布局中的按钮，这些按钮不受影响。如果我在拍完一张照片后没有再次启动相机， ImageView 就会有它的图像并且是可见的。转储 View 层次结构验证相同。据我所知，这应该是相当简单的事情，所以我不确定我哪里出错了。

更新:我还尝试在相机启动后以编程方式添加一个带有位图的全新 ImageView，并且 ImageView 也向后移动。

XML:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:id="@+id/add_activity"
    android:layout_height="fill_parent"
    >

    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/camera_preview"
        />

    <ImageView
        android:layout_width="fill_parent"
        android:id="@+id/beforeImageView"
        android:src="@drawable/app_icon"
        android:alpha="0.2"
        android:layout_height="fill_parent" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Back"
        android:id="@+id/close_camera"
        android:layout_gravity="bottom|left"
        android:layout_marginBottom="10dp"
        android:layout_marginLeft="10dp"
        android:gravity="bottom|left"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true" />

    <Button
        android:id="@+id/button_capture"
        android:text="Before"
        android:layout_width="wrap_content"
        android:layout_height="60dp"
        android:layout_gravity="center_horizontal|bottom"
        android:layout_marginBottom="20dp"
        android:background="@color/purple"
        android:textColor="@color/white"
        android:paddingLeft="5dp"
        android:paddingRight="5dp"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true" />

    <ProgressBar
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/add_progress_bar"
        android:layout_gravity="center" />

</FrameLayout>

Java:

public class AddActivity extends Activity {

    private Camera mCamera;
    CameraPreview mPreview;
    private RelativeLayout preview;
    boolean useFrontCamera = true;
    boolean tookBeforeImage = false;
    boolean tookAfterImage = false;
    Bitmap beforeImage;
    ProgressBar progressBar;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_add);

        //Hide Notification and Action Bars
        View decorView = getWindow().getDecorView();
        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);
        ActionBar actionBar = getActionBar();
        actionBar.hide();

        progressBar = (ProgressBar) findViewById(R.id.add_progress_bar);
        progressBar.setVisibility(View.INVISIBLE);

        boolean cameraCheck = checkCameraHardware(getApplicationContext());

        if (cameraCheck) {

            StartCamera cameraLaunch = new StartCamera();
            cameraLaunch.execute();

        }

        Button closeCameraButton = (Button) findViewById(R.id.close_camera);
        closeCameraButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                releaseCamera();
                View decorView = getWindow().getDecorView();
                int uiOptions = View.SYSTEM_UI_FLAG_VISIBLE;
                decorView.setSystemUiVisibility(uiOptions);
                ActionBar actionBar = getActionBar();
                actionBar.show();
                finish();
            }
        });

        Button captureButton = (Button) findViewById(R.id.button_capture);
        captureButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mCamera.takePicture(null,null,mPicture);
            }
        });
    }


    private boolean checkCameraHardware(Context context) {
        if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
            return true;
        } else {
            return false;
        }
    }

    private void releaseCamera() {
        if (mCamera != null) {
            mCamera.release();
            mCamera = null;
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        releaseCamera();
    }

    @Override
    public void onBackPressed() {
        releaseCamera();
        super.onBackPressed();
    }

    @Override
    protected void onResume() {
        super.onResume();
        //Hide Notification and Action Bars
        View decorView = getWindow().getDecorView();
        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);
        ActionBar actionBar = getActionBar();
        actionBar.hide();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        //getMenuInflater().inflate(R.menu.menu_add, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            //return true;
        }

        return super.onOptionsItemSelected(item);
    }

    private class StartCamera extends AsyncTask<String, Void, String> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progressBar.setVisibility(View.VISIBLE);
        }

        @Override
        protected String doInBackground(String... params) {
            try {
                if (useFrontCamera) {
                    mCamera = Camera.open();
                    mCamera.enableShutterSound(true);
                } else {
                    //Flip Camera
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            mPreview = new CameraPreview(getApplicationContext(),mCamera);
            preview = (RelativeLayout) findViewById(R.id.camera_preview);
            preview.addView(mPreview,0);
            progressBar.setVisibility(View.INVISIBLE);

        }
    }



    private Camera.PictureCallback mPicture = new Camera.PictureCallback() {

        @Override
        public void onPictureTaken(byte[] data, Camera camera) {

            Display display = getWindowManager().getDefaultDisplay();
            int rotation = 0;
            switch (display.getRotation()) {
                case Surface.ROTATION_0: // This is display orientation
                    rotation = 90;
                    break;
                case Surface.ROTATION_90:
                    rotation = 0;
                    break;
                case Surface.ROTATION_180:
                    rotation = 270;
                    break;
                case Surface.ROTATION_270:
                    rotation = 180;
                    break;
            }

            Bitmap bitmap = ImageTools.toBitmap(data);
            bitmap = ImageTools.rotate(bitmap, rotation);

            if (!tookBeforeImage) {
                beforeImage = bitmap;
                ResetCamera cameraReset = new ResetCamera();
                cameraReset.execute();

                Button captureButton = (Button) findViewById(R.id.button_capture);
                captureButton.setText("After");
                tookBeforeImage = true;

            } else if (tookBeforeImage == true && tookAfterImage == false) {

            } else {

            }




        }
    };

    /** A basic Camera preview class */
    public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
        private SurfaceHolder mHolder;
        private Camera mCamera;

        public CameraPreview(Context context, Camera camera) {
            super(context);
            mCamera = camera;

            // Install a SurfaceHolder.Callback so we get notified when the
            // underlying surface is created and destroyed.
            mHolder = getHolder();
            this.setBackgroundColor(Color.TRANSPARENT);
            mHolder.addCallback(this);
            // deprecated setting, but required on Android versions prior to 3.0
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }



        public void surfaceCreated(SurfaceHolder holder) {
            // The Surface has been created, now tell the camera where to draw the preview.
            try {
                mCamera.setDisplayOrientation(90);
                mCamera.setPreviewDisplay(holder);
                mCamera.startPreview();
            } catch (IOException e) {
                Log.d("Camera Error", "Error setting camera preview: " + e.getMessage());
            }
        }

        public void surfaceDestroyed(SurfaceHolder holder) {
            // empty. Take care of releasing the Camera preview in your activity.
        }

        public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
            // If your preview can change or rotate, take care of those events here.
            // Make sure to stop the preview before resizing or reformatting it.

            if (mHolder.getSurface() == null){
                // preview surface does not exist
                return;
            }

            // stop preview before making changes
            try {
                mCamera.stopPreview();
            } catch (Exception e){
                // ignore: tried to stop a non-existent preview
            }

            // set preview size and make any resize, rotate or
            // reformatting changes here

            // start preview with new settings
            try {
                mCamera.setPreviewDisplay(mHolder);
                mCamera.startPreview();

            } catch (Exception e){
                Log.d("Camera Error", "Error starting camera preview: " + e.getMessage());
            }
        }
    }

    private static class ImageTools {
        public static Bitmap toBitmap(byte[] data) {
            return BitmapFactory.decodeByteArray(data, 0, data.length);
        }

        public static Bitmap rotate(Bitmap in, int angle) {
            Matrix mat = new Matrix();
            mat.postRotate(angle);
            return Bitmap.createBitmap(in, 0, 0, in.getWidth(), in.getHeight(), mat, true);
        }
    }

    private class ResetCamera extends AsyncTask<String, Void, String> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progressBar.setVisibility(View.VISIBLE);
        }

        @Override
        protected String doInBackground(String... params) {
            mCamera.startPreview();
            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            ImageView beforeImageView = (ImageView) findViewById(R.id.beforeImageView);
            beforeImageView.setImageBitmap(beforeImage);
            beforeImageView.setImageAlpha(100);

            //Trying to add programmatically still ends up behind Camera Preview
            ImageView newBefore = (ImageView) new ImageView(getApplicationContext());
            newBefore.setImageBitmap(beforeImage);
            newBefore.setLayoutParams(new ViewGroup.LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT,
                    ViewGroup.LayoutParams.WRAP_CONTENT));
            preview.addView(newBefore,0);

            progressBar.setVisibility(View.INVISIBLE);
        }
    }




}

Answer 1

这是由于试图加载太大的位图，它在日志中悄悄地抛出一条通知，因为它无法创建纹理。减小位图的大小解决了这个问题。