always use the proper aspect ratio at preview

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

@@ -1,6 +1,7 @@
 package com.simplemobiletools.camera;
 
 import android.content.Context;
+import android.graphics.Point;
 import android.graphics.Rect;
 import android.hardware.Camera;
 import android.media.CamcorderProfile;
@@ -47,10 +48,13 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
     private static boolean isSurfaceCreated;
     private static boolean switchToVideoAsap;
     private static boolean isVideoCaptureIntent;
+    private boolean setupPreviewAfterMeasure;
     private static String curVideoPath;
     private static int lastClickX;
     private static int lastClickY;
     private static int initVideoRotation;
+    private static int navBarHeight;
+    private static Point screenSize;
     private static Uri targetUri;
 
     public Preview(Context context) {
@@ -73,7 +77,10 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
         isFlashEnabled = false;
         isVideoMode = false;
         isSurfaceCreated = false;
+        setupPreviewAfterMeasure = false;
         curVideoPath = "";
+        navBarHeight = Utils.getNavBarHeight(getResources());
+        screenSize = Utils.getScreenSize(activity);
     }
 
     public void trySwitchToVideo() {
@@ -111,6 +118,8 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
             parameters = camera.getParameters();
             supportedPreviewSizes = parameters.getSupportedPreviewSizes();
             requestLayout();
+            invalidate();
+            setupPreviewAfterMeasure = true;
 
             final List<String> focusModes = parameters.getSupportedFocusModes();
             if (focusModes.contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE))
@@ -127,7 +136,6 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
                     Log.e(TAG, "setCamera setPreviewDisplay " + e.getMessage());
                     return false;
                 }
-                setupPreview();
             }
 
             callback.setFlashAvailable(Utils.hasFlash(camera));
@@ -359,25 +367,12 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
     @Override
     public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
         isSurfaceCreated = true;
-        setupPreview();
 
         if (isVideoMode) {
             initRecorder();
         }
     }
 
-    private void setupPreview() {
-        canTakePicture = true;
-        if (camera != null && previewSize != null) {
-            parameters.setPreviewSize(previewSize.width, previewSize.height);
-
-            requestLayout();
-
-            camera.setParameters(parameters);
-            camera.startPreview();
-        }
-    }
-
     @Override
     public void surfaceDestroyed(SurfaceHolder holder) {
         isSurfaceCreated = false;
@@ -388,6 +383,15 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
         cleanupRecorder();
     }
 
+    private void setupPreview() {
+        canTakePicture = true;
+        if (camera != null && previewSize != null) {
+            parameters.setPreviewSize(previewSize.width, previewSize.height);
+            camera.setParameters(parameters);
+            camera.startPreview();
+        }
+    }
+
     private void cleanupRecorder() {
         if (recorder != null) {
             if (isRecording) {
@@ -438,12 +442,25 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
 
     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
-        final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
+        setMeasuredDimension(screenSize.x, screenSize.y);
-        final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
-        setMeasuredDimension(width, height);
 
         if (supportedPreviewSizes != null) {
-            previewSize = getOptimalPreviewSize(supportedPreviewSizes, width, height);
+            previewSize = getOptimalPreviewSize(supportedPreviewSizes, screenSize.x, screenSize.y);
+            final LayoutParams lp = surfaceView.getLayoutParams();
+
+            if (screenSize.x > previewSize.height) {
+                final float ratio = (float) screenSize.x / previewSize.height;
+                lp.width = (int) (previewSize.height * ratio);
+                lp.height = (int) (previewSize.width * ratio);
+            } else {
+                lp.width = previewSize.height;
+                lp.height = previewSize.width;
+            }
+
+            if (setupPreviewAfterMeasure) {
+                setupPreviewAfterMeasure = false;
+                setupPreview();
+            }
         }
     }
 

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

@@ -1,13 +1,16 @@
 package com.simplemobiletools.camera;
 
 import android.Manifest;
+import android.app.Activity;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.content.res.Resources;
+import android.graphics.Point;
 import android.hardware.Camera;
 import android.media.MediaScannerConnection;
 import android.os.Environment;
 import android.support.v4.content.ContextCompat;
+import android.view.Display;
 import android.widget.Toast;
 
 import java.io.File;
@@ -97,6 +100,28 @@ public class Utils {
         return sb.toString();
     }
 
+    public static Point getScreenSize(Activity activity) {
+        final Display display = activity.getWindowManager().getDefaultDisplay();
+        final Point size = new Point();
+        display.getSize(size);
+        size.y += getNavBarHeight(activity.getResources());
+        return size;
+    }
+
+    public static int getNavBarHeight(Resources res) {
+        int id = res.getIdentifier("navigation_bar_height", "dimen", "android");
+        if (id > 0 && hasNavBar(res)) {
+            return res.getDimensionPixelSize(id);
+        }
+
+        return 0;
+    }
+
+    public static boolean hasNavBar(Resources res) {
+        int id = res.getIdentifier("config_showNavigationBar", "bool", "android");
+        return id > 0 && res.getBoolean(id);
+    }
+
     public static boolean hasCameraPermission(Context cxt) {
         return ContextCompat.checkSelfPermission(cxt, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED;
     }

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

@@ -3,7 +3,8 @@
     android:id="@+id/viewHolder"
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_height="match_parent"
+    android:background="@android:color/black">
 
     <SurfaceView
         android:id="@+id/surfaceView"