Remove unused codes

app/src/main/java/com/hippo/ehviewer/preference/SignOutPreference.java

@@ -16,31 +16,39 @@
 
 package com.hippo.ehviewer.preference;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.util.AttributeSet;
-import android.widget.Toast;
 
 import androidx.appcompat.app.AlertDialog;
 
 import com.hippo.ehviewer.R;
 import com.hippo.ehviewer.client.EhUtils;
+import com.hippo.ehviewer.ui.SettingsActivity;
+import com.hippo.ehviewer.ui.scene.BaseScene;
 import com.hippo.preference.MessagePreference;
 
 public class SignOutPreference extends MessagePreference {
 
+    @SuppressLint("StaticFieldLeak")
+    private final SettingsActivity mActivity;
+
     public SignOutPreference(Context context) {
         super(context);
         init();
+        mActivity = (SettingsActivity) context;
     }
 
     public SignOutPreference(Context context, AttributeSet attrs) {
         super(context, attrs);
         init();
+        mActivity = (SettingsActivity) context;
     }
 
     public SignOutPreference(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
         init();
+        mActivity = (SettingsActivity) context;
     }
 
     private void init() {
@@ -51,6 +59,7 @@ public class SignOutPreference extends MessagePreference {
     protected void onPrepareDialogBuilder(AlertDialog.Builder builder) {
         super.onPrepareDialogBuilder(builder);
         builder.setPositiveButton(R.string.settings_eh_sign_out_yes, this);
+        builder.setNegativeButton(android.R.string.cancel, null);
     }
 
     @Override
@@ -58,7 +67,7 @@ public class SignOutPreference extends MessagePreference {
         super.onDialogClosed(positiveResult);
         if (positiveResult) {
             EhUtils.signOut(getContext());
-            Toast.makeText(getContext(), R.string.settings_eh_sign_out_tip, Toast.LENGTH_SHORT).show();
+            mActivity.showTip(R.string.settings_eh_sign_out_tip, BaseScene.LENGTH_SHORT);
         }
     }
 }