New feature “Text and reading options” for SetupWizard, Wallpaper, and Settings (4/n).

- Extending the interface of AppGridView to be flexible. It will be used
in the TextReadingPreferenceFragment.
  1. Add a new attribute "appCounts" into the view.
  2. Default app counts as 6 if not set the attribute.

Bug: 211503117
Test: make -j64 RunSettingsRoboTests ROBOTEST_FILTER=AppGridViewTest
Change-Id: I94a5f1d037551f6faba0300a176feb11fba1f203

src/com/android/settings/display/AppGridView.java

@@ -20,10 +20,12 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
+import android.content.res.TypedArray;
 import android.graphics.drawable.Drawable;
 import android.os.UserHandle;
 import android.util.AttributeSet;
 import android.util.IconDrawableFactory;
+import android.util.Log;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ArrayAdapter;
@@ -31,6 +33,7 @@ import android.widget.GridView;
 import android.widget.ImageView;
 
 import androidx.annotation.VisibleForTesting;
+import androidx.core.util.Preconditions;
 
 import com.android.settings.R;
 
@@ -38,7 +41,18 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * The grid view for displaying the application entries.
+ *
+ * <p> The attribute value {@code appCount} from XML should be more than or equal to 1, otherwise
+ * throws an {@link IllegalArgumentException}.</p>
+ */
 public class AppGridView extends GridView {
+    private static final String TAG = "AppGridView";
+
+    private static final int APP_COUNT_DEF_VALUE = 6;
+    private int mAppCount = APP_COUNT_DEF_VALUE;
+
     public AppGridView(Context context) {
         super(context);
         init(context);
@@ -46,24 +60,36 @@ public class AppGridView extends GridView {
 
     public AppGridView(Context context, AttributeSet attrs) {
         super(context, attrs);
+        applyAttributeSet(context, attrs);
         init(context);
     }
 
     public AppGridView(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
+        applyAttributeSet(context, attrs);
         init(context);
     }
 
     public AppGridView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleResId) {
         super(context, attrs, defStyleAttr, defStyleResId);
-
+        applyAttributeSet(context, attrs);
         init(context);
-
     }
 
     private void init(Context context) {
         setAdapter(new AppsAdapter(context, R.layout.screen_zoom_preview_app_icon,
-                android.R.id.text1, android.R.id.icon1));
+                android.R.id.text1, android.R.id.icon1, mAppCount));
+    }
+
+    private void applyAttributeSet(Context context, AttributeSet attrs) {
+        final TypedArray styledAttrs =
+                context.obtainStyledAttributes(attrs, R.styleable.AppGridView);
+        mAppCount =
+                styledAttrs.getInteger(R.styleable.AppGridView_appCount, APP_COUNT_DEF_VALUE);
+        Preconditions.checkArgument(mAppCount >= 1,
+                /* errorMessage= */ "App count may not be negative or zero");
+
+        styledAttrs.recycle();
     }
 
     /**
@@ -73,12 +99,15 @@ public class AppGridView extends GridView {
     public static class AppsAdapter extends ArrayAdapter<ActivityEntry> {
         private final PackageManager mPackageManager;
         private final int mIconResId;
+        private final int mAppCount;
 
-        public AppsAdapter(Context context, int layout, int textResId, int iconResId) {
+        public AppsAdapter(Context context, int layout, int textResId, int iconResId,
+                int appCount) {
             super(context, layout, textResId);
 
             mIconResId = iconResId;
             mPackageManager = context.getPackageManager();
+            mAppCount = appCount;
 
             loadAllApps();
         }
@@ -108,20 +137,24 @@ public class AppGridView extends GridView {
         }
 
         private void loadAllApps() {
-            final int needAppCount = 6;
             final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
             mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
 
             final PackageManager pm = mPackageManager;
             final ArrayList<ActivityEntry> results = new ArrayList<>();
             final List<ResolveInfo> infos = pm.queryIntentActivities(mainIntent, 0);
+
+            if (mAppCount > infos.size()) {
+                Log.d(TAG, "Visible app icon count does not meet the target count.");
+            }
+
             final IconDrawableFactory iconFactory = IconDrawableFactory.newInstance(getContext());
             for (ResolveInfo info : infos) {
                 final CharSequence label = info.loadLabel(pm);
                 if (label != null) {
                     results.add(new ActivityEntry(info, label.toString(), iconFactory));
                 }
-                if (results.size() >= needAppCount) {
+                if (results.size() >= mAppCount) {
                     break;
                 }
             }