add camera preview

app/build.gradle

@@ -23,4 +23,5 @@ dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     testCompile 'junit:junit:4.12'
     compile 'com.android.support:appcompat-v7:23.3.0'
+    compile 'com.jakewharton:butterknife:7.0.1'
 }

app/src/main/java/com/simplemobiletools/camera/MainActivity.java

@@ -4,16 +4,28 @@ import android.hardware.Camera;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
 import android.util.Log;
+import android.view.SurfaceHolder;
+import android.view.SurfaceView;
 
-public class MainActivity extends AppCompatActivity {
+import butterknife.Bind;
+import butterknife.ButterKnife;
+
+public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback {
     private static final String TAG = MainActivity.class.getSimpleName();
+
+    @Bind(R.id.surfaceView) SurfaceView surfaceView;
     private Camera camera;
     private boolean isOpen;
+    private SurfaceHolder surfaceHolder;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
+        ButterKnife.bind(this);
+
+        surfaceHolder = surfaceView.getHolder();
+        surfaceHolder.addCallback(this);
     }
 
     @Override
@@ -34,7 +46,13 @@ public class MainActivity extends AppCompatActivity {
         try {
             releaseCamera();
             camera = Camera.open();
-            isOpen = (camera != null);
+
+            if (camera != null) {
+                isOpen = true;
+                camera.setDisplayOrientation(90);
+                camera.setPreviewDisplay(surfaceHolder);
+                camera.startPreview();
+            }
         } catch (Exception e) {
             Log.e(TAG, "openCamera exception " + e.getMessage());
         }
@@ -46,4 +64,22 @@ public class MainActivity extends AppCompatActivity {
             camera = null;
         }
     }
+
+    @Override
+    public void surfaceCreated(SurfaceHolder holder) {
+        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
+        openCamera();
+    }
+
+    @Override
+    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
+
+    }
+
+    @Override
+    public void surfaceDestroyed(SurfaceHolder holder) {
+        if (camera != null) {
+            camera.stopPreview();
+        }
+    }
 }

app/src/main/res/layout/activity_main.xml

@@ -2,10 +2,11 @@
 <RelativeLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="match_parent"
-    android:paddingBottom="@dimen/activity_vertical_margin"
-    android:paddingLeft="@dimen/activity_horizontal_margin"
-    android:paddingRight="@dimen/activity_horizontal_margin"
-    android:paddingTop="@dimen/activity_vertical_margin">
+    android:layout_height="match_parent">
+
+    <SurfaceView
+        android:id="@+id/surfaceView"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
 
 </RelativeLayout>