Create logic for applying padding only to custom preference layouts

n the case of any standard PreferenceFragment layout, we can
change the list styling to add padding and set clipToPadding to false.
In this case, we don't want extra padding in the parent ViewGroup
(R.id.prefs).
When an app specifies a custom preference fragment layout, we want
to add the previously existing padding styles R.id.prefs.

Change-Id: Idfd77dcbef264c6f5f4121b66fd54c684ad0a288

1 files changed, 84 insertions, 0 deletions

diff --git a/core/java/android/preference/PreferenceFrameLayout.java b/core/java/android/preference/PreferenceFrameLayout.java
new file mode 100644
index 0000000..426abf0
--- /dev/null
+++ b/core/java/android/preference/PreferenceFrameLayout.java
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.preference;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.FrameLayout;
+
+/**
+ * @hide
+ */
+public class PreferenceFrameLayout extends FrameLayout {
+    private static final int DEFAULT_TOP_PADDING = 0;
+    private static final int DEFAULT_BOTTOM_PADDING = 0;
+    private final int mTopPadding;
+    private final int mBottomPadding;
+    private boolean mPaddingApplied = false;
+
+    public PreferenceFrameLayout(Context context) {
+        this(context, null);
+    }
+
+    public PreferenceFrameLayout(Context context, AttributeSet attrs) {
+        this(context, attrs, com.android.internal.R.attr.preferenceFrameLayoutStyle);
+    }
+
+    public PreferenceFrameLayout(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        TypedArray a = context.obtainStyledAttributes(attrs,
+                com.android.internal.R.styleable.PreferenceFrameLayout, defStyle, 0);
+
+        mTopPadding = (int) a.getDimension(
+                com.android.internal.R.styleable.PreferenceFrameLayout_topPadding,
+                DEFAULT_TOP_PADDING);
+        mBottomPadding = (int) a.getDimension(
+                com.android.internal.R.styleable.PreferenceFrameLayout_bottomPadding,
+                DEFAULT_BOTTOM_PADDING);
+
+        a.recycle();
+    }
+
+    @Override
+    public void addView(View child) {
+        int topPadding = getPaddingTop();
+        int bottomPadding = getPaddingBottom();
+        // Check on the id of the child before adding it.
+        if (child != null && child.getId() != com.android.internal.R.id.default_preference_layout) {
+            // Add the padding to the view group after determining if the padding already exists.
+            if (!mPaddingApplied) {
+                topPadding += mTopPadding;
+                bottomPadding += mBottomPadding;
+                mPaddingApplied = true;
+            }
+        } else {
+            if (mPaddingApplied) {
+                topPadding -= mTopPadding;
+                bottomPadding -= mBottomPadding;
+                mPaddingApplied = false;
+            }
+        }
+        int previousTop = getPaddingTop();
+        int previousBottom = getPaddingBottom();
+        if (previousTop != topPadding || previousBottom != bottomPadding) {
+            setPadding(getPaddingLeft(), topPadding, getPaddingRight(), bottomPadding);
+        }
+        super.addView(child);
+    }
+}
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