Clean up

app/src/main/java/com/hippo/app/AppCompatPreferenceActivity.java

@@ -37,7 +37,7 @@ import android.view.MenuInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-public class AppCompatPreferenceActivity extends PreferenceActivity implements AppCompatCallback,
+public abstract class AppCompatPreferenceActivity extends PreferenceActivity implements AppCompatCallback,
         TaskStackBuilder.SupportParentable, ActionBarDrawerToggle.DelegateProvider {
 
     private AppCompatDelegate mDelegate;

app/src/main/java/com/hippo/ehviewer/ui/EhActivity.java

@@ -24,7 +24,7 @@ import com.google.analytics.tracking.android.EasyTracker;
 import com.hippo.ehviewer.EhApplication;
 import com.hippo.ehviewer.Settings;
 
-public class EhActivity extends AppCompatActivity {
+public abstract class EhActivity extends AppCompatActivity {
 
     private boolean mTrackStarted;
 

app/src/main/java/com/hippo/ehviewer/ui/EhPreferenceActivity.java

@@ -24,7 +24,7 @@ import com.hippo.app.AppCompatPreferenceActivity;
 import com.hippo.ehviewer.EhApplication;
 import com.hippo.ehviewer.Settings;
 
-public class EhPreferenceActivity extends AppCompatPreferenceActivity {
+public abstract class EhPreferenceActivity extends AppCompatPreferenceActivity {
 
     private boolean mTrackStarted;
 

app/src/main/java/com/hippo/ehviewer/ui/ToolbarActivity.java

@@ -26,7 +26,7 @@ import android.view.ViewGroup;
 
 import com.hippo.ehviewer.R;
 
-public class ToolbarActivity extends EhActivity {
+public abstract class ToolbarActivity extends EhActivity {
 
     @Override
     public void setContentView(@LayoutRes int layoutResID) {

app/src/main/java/com/hippo/gl/glrenderer/GLES20Canvas.java

@@ -33,6 +33,7 @@ import java.nio.ByteOrder;
 import java.nio.FloatBuffer;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Locale;
 
 public class GLES20Canvas implements GLCanvas {
     // ************** Constants **********************
@@ -885,7 +886,7 @@ public class GLES20Canvas implements GLCanvas {
 
     @Override
     public void dumpStatisticsAndClear() {
-        String line = String.format("MESH:%d, TEX_RECT:%d, FILL_RECT:%d, LINE:%d", mCountDrawMesh,
+        String line = String.format(Locale.US, "MESH:%d, TEX_RECT:%d, FILL_RECT:%d, LINE:%d", mCountDrawMesh,
                 mCountTextureRect, mCountFillRect, mCountDrawLine);
         mCountDrawMesh = 0;
         mCountTextureRect = 0;

app/src/main/java/com/hippo/scene/SceneApplication.java

@@ -21,7 +21,7 @@ import android.util.SparseArray;
 
 import com.hippo.yorozuya.IntIdGenerator;
 
-public class SceneApplication extends Application {
+public abstract class SceneApplication extends Application {
 
     private final IntIdGenerator mIdGenerator = new IntIdGenerator();
     private final SparseArray<StageActivity> mStageMap = new SparseArray<>();