ImageView 在相机表面视图后面移动

Posted 2023-04-17

【中文标题】ImageView 在相机表面视图后面移动

【英文标题】：ImageView moving behind Camera Surface View

【发布时间】：2015-01-04 23:44:13

【问题描述】：

我试图在相机表面视图上放置一个图像视图，当应用程序启动时，图像视图位于相机预览的顶部，但在拍摄照片并设置为图像视图后，相机预览嵌套在移动中的 RelativeLayout当调用 startpreview 以再次启动相机时前进，因此相机预览最终位于图像视图上方。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。如果我在一张图片后没有再次启动相机，则 imageview 有它的图像并且是可见的。转储视图层次结构验证相同。据我所知，这应该是相当直截了当的事情，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 也被移到后面。

XML：

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

    <RelativeLayout
        android:layout_
        android:layout_
        android:id="@+id/camera_preview"
        />

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

    <Button
        android:layout_
        android:layout_
        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_
        android:layout_
        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_
        android:layout_
        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);
        
    

【参考方案1】：

这是由于试图加载太大的位图，它正在悄悄地在日志中抛出一个通知，因为它无法创建纹理。减小位图的大小解决了这个问题。