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      1 /*
      2 * Copyright 2017 The Android Open Source Project
      3 *
      4 * Licensed under the Apache License, Version 2.0 (the "License");
      5 * you may not use this file except in compliance with the License.
      6 * You may obtain a copy of the License at
      7 *
      8 *     http://www.apache.org/licenses/LICENSE-2.0
      9 *
     10 * Unless required by applicable law or agreed to in writing, software
     11 * distributed under the License is distributed on an "AS IS" BASIS,
     12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 * See the License for the specific language governing permissions and
     14 * limitations under the License.
     15 */
     16 
     17 package com.example.android.basicpermissions.camera
     18 
     19 import android.content.Context
     20 import android.hardware.Camera
     21 import android.util.AttributeSet
     22 import android.util.Log
     23 import android.view.SurfaceHolder
     24 import android.view.SurfaceView
     25 import com.example.android.basicpermissions.util.calculatePreviewOrientation
     26 
     27 import java.io.IOException
     28 
     29 /**
     30  * Camera preview that displays a [Camera].
     31  *
     32  *
     33  * Handles basic lifecycle methods to display and stop the preview.
     34  *
     35  *
     36  * Implementation is based directly on the documentation at
     37  * http://developer.android.com/guide/topics/media/camera.html
     38  */
     39 class CameraPreview @JvmOverloads constructor(
     40         context: Context,
     41         attrs: AttributeSet? = null,
     42         defStyleAttr: Int = 0,
     43         private val camera: Camera? = null,
     44         private val cameraInfo: Camera.CameraInfo? = null,
     45         private val displayOrientation: Int = 0
     46 ) : SurfaceView(context, attrs, defStyleAttr), SurfaceHolder.Callback {
     47 
     48     init {
     49 
     50         // Do not initialise if no camera has been set
     51         if (camera != null && cameraInfo != null) {
     52             // Install a SurfaceHolder.Callback so we get notified when the
     53             // underlying surface is created and destroyed.
     54             holder.addCallback(this@CameraPreview)
     55         }
     56     }
     57 
     58     override fun surfaceCreated(holder: SurfaceHolder) {
     59         // The Surface has been created, now tell the camera where to draw the preview.
     60         try {
     61             camera?.run {
     62                 setPreviewDisplay(holder)
     63                 startPreview()
     64             }
     65             Log.d(TAG, "Camera preview started.")
     66         } catch (e: IOException) {
     67             Log.d(TAG, "Error setting camera preview: ${e.message}")
     68         }
     69 
     70     }
     71 
     72     override fun surfaceDestroyed(holder: SurfaceHolder) {
     73         // empty. Take care of releasing the Camera preview in your activity.
     74     }
     75 
     76     override fun surfaceChanged(holder: SurfaceHolder, format: Int, w: Int, h: Int) {
     77         // If your preview can change or rotate, take care of those events here.
     78         // Make sure to stop the preview before resizing or reformatting it.
     79 
     80         if (holder.surface == null) {
     81             // preview surface does not exist
     82             Log.d(TAG, "Preview surface does not exist")
     83             return
     84         }
     85         Log.d(TAG, "Preview stopped.")
     86         camera?.run {
     87             // stop preview before making changes
     88             stopPreview()
     89             cameraInfo?.let {
     90                 setDisplayOrientation(it.calculatePreviewOrientation(displayOrientation))
     91             }
     92             setPreviewDisplay(holder)
     93             startPreview()
     94             Log.d(TAG, "Camera preview started.")
     95         }
     96     }
     97 
     98     companion object {
     99         private val TAG = "CameraPreview"
    100     }
    101 }
    102