make the camera preview fullscreen

app/src/main/AndroidManifest.xml

@@ -16,7 +16,7 @@
         android:theme="@style/AppTheme">
         <activity
             android:name=".MainActivity"
-            android:screenOrientation="portrait">
+            android:screenOrientation="landscape">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
 

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

@@ -4,82 +4,50 @@ 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;
+import android.view.ViewGroup;
+import android.view.Window;
+import android.view.WindowManager;
+import android.widget.RelativeLayout;
 
 import butterknife.Bind;
 import butterknife.ButterKnife;
 
-public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback {
+public class MainActivity extends AppCompatActivity {
-    private static final String TAG = MainActivity.class.getSimpleName();
+    @Bind(R.id.viewHolder) RelativeLayout viewHolder;
 
-    @Bind(R.id.surfaceView) SurfaceView surfaceView;
+    private static final String TAG = Preview.class.getSimpleName();
-    private Camera camera;
+    private Preview preview;
-    private boolean isOpen;
-    private SurfaceHolder surfaceHolder;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        requestWindowFeature(Window.FEATURE_NO_TITLE);
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
+
         setContentView(R.layout.activity_main);
         ButterKnife.bind(this);
 
-        surfaceHolder = surfaceView.getHolder();
+        preview = new Preview(this, (SurfaceView) findViewById(R.id.surfaceView));
-        surfaceHolder.addCallback(this);
+        preview.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
+        viewHolder.addView(preview);
     }
 
     @Override
     protected void onResume() {
         super.onResume();
-        openCamera();
+
+        try {
+            Camera camera = Camera.open(0);
+            preview.setCamera(camera);
+        } catch (Exception e) {
+            Log.e(TAG, "onResume IOException " + e.getMessage());
+        }
     }
 
     @Override
     protected void onPause() {
         super.onPause();
-        releaseCamera();
+        preview.releaseCamera();
-    }
-
-    private void openCamera() {
-        isOpen = false;
-
-        try {
-            releaseCamera();
-            camera = Camera.open();
-
-            if (camera != null) {
-                isOpen = true;
-                camera.setDisplayOrientation(90);
-                camera.setPreviewDisplay(surfaceHolder);
-                camera.startPreview();
-            }
-        } catch (Exception e) {
-            Log.e(TAG, "openCamera exception " + e.getMessage());
-        }
-    }
-
-    private void releaseCamera() {
-        if (camera != null) {
-            camera.release();
-            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/java/com/simplemobiletools/camera/Preview.java

@@ -0,0 +1,159 @@
+package com.simplemobiletools.camera;
+
+import android.content.Context;
+import android.hardware.Camera;
+import android.util.Log;
+import android.view.SurfaceHolder;
+import android.view.SurfaceView;
+import android.view.View;
+import android.view.ViewGroup;
+
+import java.io.IOException;
+import java.util.List;
+
+public class Preview extends ViewGroup implements SurfaceHolder.Callback {
+    private static final String TAG = Preview.class.getSimpleName();
+
+    private SurfaceHolder surfaceHolder;
+    private Camera camera;
+    private List<Camera.Size> supportedPreviewSizes;
+    private SurfaceView surfaceView;
+    private Camera.Size previewSize;
+
+    public Preview(Context context) {
+        super(context);
+    }
+
+    public Preview(Context context, SurfaceView sv) {
+        super(context);
+
+        surfaceView = sv;
+        surfaceHolder = surfaceView.getHolder();
+        surfaceHolder.addCallback(this);
+        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
+    }
+
+    public void setCamera(Camera newCamera) {
+        if (camera == newCamera) {
+            return;
+        }
+
+        releaseCamera();
+        camera = newCamera;
+
+        if (camera != null) {
+            supportedPreviewSizes = camera.getParameters().getSupportedPreviewSizes();
+            requestLayout();
+
+            final Camera.Parameters params = camera.getParameters();
+            params.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
+            camera.setParameters(params);
+        }
+    }
+
+    public void releaseCamera() {
+        if (camera != null) {
+            camera.stopPreview();
+            camera.release();
+            camera = null;
+        }
+    }
+
+    @Override
+    public void surfaceCreated(SurfaceHolder holder) {
+        try {
+            if (camera != null) {
+                camera.setPreviewDisplay(holder);
+            }
+        } catch (IOException e) {
+            Log.e(TAG, "surfaceCreated IOException " + e.getMessage());
+        }
+    }
+
+    @Override
+    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
+        if (camera != null) {
+            final Camera.Parameters parameters = camera.getParameters();
+            parameters.setPreviewSize(previewSize.width, previewSize.height);
+            requestLayout();
+
+            camera.setParameters(parameters);
+            camera.startPreview();
+        }
+    }
+
+    @Override
+    public void surfaceDestroyed(SurfaceHolder holder) {
+        if (camera != null) {
+            camera.stopPreview();
+        }
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int l, int t, int r, int b) {
+        if (changed && getChildCount() > 0) {
+            final View child = getChildAt(0);
+
+            final int width = r - l;
+            final int height = b - t;
+
+            int previewWidth = width;
+            int previewHeight = height;
+            if (previewSize != null) {
+                previewWidth = previewSize.width;
+                previewHeight = previewSize.height;
+            }
+
+            if (width * previewHeight > height * previewWidth) {
+                final int scaledChildWidth = previewWidth * height / previewHeight;
+                child.layout((width - scaledChildWidth) / 2, 0, (width + scaledChildWidth) / 2, height);
+            } else {
+                final int scaledChildHeight = previewHeight * width / previewWidth;
+                child.layout(0, (height - scaledChildHeight) / 2, width, (height + scaledChildHeight) / 2);
+            }
+        }
+    }
+
+    private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
+        final double ASPECT_TOLERANCE = 0.1;
+        double targetRatio = (double) h / w;
+
+        if (sizes == null)
+            return null;
+
+        Camera.Size optimalSize = null;
+        double minDiff = Double.MAX_VALUE;
+
+        for (Camera.Size size : sizes) {
+            double ratio = (double) size.width / size.height;
+            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
+                continue;
+            if (Math.abs(size.height - h) < minDiff) {
+                optimalSize = size;
+                minDiff = Math.abs(size.height - h);
+            }
+        }
+
+        if (optimalSize == null) {
+            minDiff = Double.MAX_VALUE;
+            for (Camera.Size size : sizes) {
+                if (Math.abs(size.height - h) < minDiff) {
+                    optimalSize = size;
+                    minDiff = Math.abs(size.height - h);
+                }
+            }
+        }
+        return optimalSize;
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
+        final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
+        setMeasuredDimension(width, height);
+
+        if (supportedPreviewSizes != null) {
+            previewSize = getOptimalPreviewSize(supportedPreviewSizes, width, height);
+        }
+    }
+}

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

@@ -1,12 +1,13 @@
 <?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout
+    android:id="@+id/viewHolder"
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
     <SurfaceView
         android:id="@+id/surfaceView"
-        android:layout_width="match_parent"
+        android:layout_width="wrap_content"
-        android:layout_height="match_parent"/>
+        android:layout_height="wrap_content"/>
 
 </RelativeLayout>

app/src/main/res/values/styles.xml

@@ -1,8 +1,6 @@
 <resources>
 
-    <!-- Base application theme. -->
+    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
-    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
-        <!-- Customize your theme here. -->
         <item name="colorPrimary">@color/colorPrimary</item>
         <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
         <item name="colorAccent">@color/colorAccent</item>