Avoid constant view inflation on viewer sample app

The previous approach re-inflated views on every frame simply because the FPS
number changed (which was passed in a JSON object and used to check whether
the old view matched the new one based on a tag on the view that was set by
the previous FPS string).

The new approach is not pretty (there's no reason to even re-populate the
views when the only thing that needs to happen is to set the appropriate
FPS info in the floating TextView), but at least this avoids the inflation
overhead of the previous approach.

BUG=skia:

Change-Id: Ide1c736c49663cfcf478653a7cdaa99c736f1783
Reviewed-on: https://skia-review.googlesource.com/8461
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Chet Haase <chet@google.com>

1 files changed, 40 insertions, 23 deletions

diff --git a/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/StateAdapter.java b/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/StateAdapter.java
index 3aea9659be..332ef03c9f 100644
--- a/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/StateAdapter.java
+++ b/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/StateAdapter.java
@@ -118,14 +118,16 @@ public class StateAdapter extends BaseAdapter implements AdapterView.OnItemSelec
         }
     }
 
-    private View inflateItemView(JSONObject item) throws JSONException {
-        LinearLayout itemView = (LinearLayout)
-                LayoutInflater.from(mViewerActivity).inflate(R.layout.state_item, null);
+    private void populateView(JSONObject item, View view) throws JSONException {
+        LinearLayout itemView = (LinearLayout) view;
         TextView nameText = (TextView) itemView.findViewById(R.id.nameText);
         TextView valueText = (TextView) itemView.findViewById(R.id.valueText);
         Spinner optionSpinner = (Spinner) itemView.findViewById(R.id.optionSpinner);
-        nameText.setText(item.getString(NAME));
+
         String value = item.getString(VALUE);
+        itemView.setTag(item.toString()); // To save unnecessary view update
+
+        nameText.setText(item.getString(NAME));
 
         if (nameText.getText().equals(FPS_STATE_NAME) && mFPSFloatText != null) {
             mFPSFloatText.setText(value);
@@ -149,27 +151,38 @@ public class StateAdapter extends BaseAdapter implements AdapterView.OnItemSelec
             adapter.setCurrentOption(value);
             optionSpinner.setAdapter(adapter);
             if (optionStrings.length >= FILTER_LENGTH) {
-                EditText filterText = new EditText(mViewerActivity);
-                filterText.setHint("Filter");
-                itemView.addView(filterText, 1);
-                filterText.addTextChangedListener(new TextWatcher() {
-                    @Override
-                    public void beforeTextChanged(CharSequence s, int start, int cnt, int after) {}
-                    @Override
-                    public void onTextChanged(CharSequence s, int start, int before, int cnt) {}
-                    @Override
-                    public void afterTextChanged(Editable s) {
-                        adapter.getFilter().filter(s.toString());
-                    }
-                });
+                View existingView = itemView.getChildAt(1);
+                if (!(existingView instanceof EditText)) {
+                    EditText filterText = new EditText(mViewerActivity);
+                    filterText.setHint("Filter");
+                    itemView.addView(filterText, 1);
+                    filterText.addTextChangedListener(new TextWatcher() {
+                        @Override
+                        public void beforeTextChanged(CharSequence s, int start, int cnt,
+                                int after) {
+                        }
+
+                        @Override
+                        public void onTextChanged(CharSequence s, int start, int before, int cnt) {
+                        }
+
+                        @Override
+                        public void afterTextChanged(Editable s) {
+                            adapter.getFilter().filter(s.toString());
+                        }
+                    });
+                }
             }
             optionSpinner.setSelection(optionList.indexOf(value));
             optionSpinner.setOnItemSelectedListener(this);
             optionSpinner.setVisibility(View.VISIBLE);
             valueText.setVisibility(View.GONE);
         }
-        itemView.setTag(item.toString()); // To save unnecessary view update
-        itemView.setTag(R.integer.value_tag_key, value); // To save unnecessary state change event
+    }
+    private View inflateItemView(JSONObject item) throws JSONException {
+        LinearLayout itemView = (LinearLayout)
+                LayoutInflater.from(mViewerActivity).inflate(R.layout.state_item, null);
+        populateView(item, itemView);
         return itemView;
     }
 
@@ -181,15 +194,16 @@ public class StateAdapter extends BaseAdapter implements AdapterView.OnItemSelec
             }
             for (int i = 0; i < mStateJson.length(); i++) {
                 JSONObject stateObject = mStateJson.getJSONObject(i);
-                if (mLayout.getChildCount() > i) {
-                    View childView = mLayout.getChildAt(i);
+                View childView = mLayout.getChildAt(i);
+                if (childView != null) {
                     if (stateObject.toString().equals(childView.getTag())) {
                         continue; // No update, reuse the old view and skip the remaining step
                     } else {
-                        mLayout.removeViewAt(i);
+                        populateView(stateObject, childView);
                     }
+                } else {
+                    mLayout.addView(inflateItemView(stateObject), i);
                 }
-                mLayout.addView(inflateItemView(stateObject), i);
             }
         } catch (JSONException e) {
             e.printStackTrace();
@@ -198,6 +212,9 @@ public class StateAdapter extends BaseAdapter implements AdapterView.OnItemSelec
 
     @Override
     public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
+        if (view == null) {
+            return;
+        }
         View stateItem = (View) parent.getParent();
         String stateName = ((TextView) stateItem.findViewById(R.id.nameText)).getText().toString();
         String stateValue = ((TextView) view).getText().toString();