Add breakStrategy attribute to TextView
This patch adds plumbing to TextView to control the strategy used
for breaking paragraphs into lines.
The default for TextView is "quality", while the default for EditText
is "simple", largely to avoid too much re-layout when editing.
StaticLayout now has a builder which provides access to more
functionality and is also cleaner than the old mechanism of having
lots of constructors with varying numbers of arguments. This patch
changes TextView to use that builder, and also contains cleanups
of the Builder within StaticLayout.
Change-Id: Iee3cf3a05a3e51ba0834554e4a3ec606e9cabca5
diff --git a/core/java/android/text/Layout.java b/core/java/android/text/Layout.java
index 22abb18..16ae5e2 100644
--- a/core/java/android/text/Layout.java
+++ b/core/java/android/text/Layout.java
@@ -16,6 +16,7 @@
package android.text;
+import android.annotation.IntDef;
import android.emoji.EmojiFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
@@ -33,6 +34,8 @@
import com.android.internal.util.ArrayUtils;
import com.android.internal.util.GrowingArrayUtils;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
import java.util.Arrays;
/**
@@ -43,6 +46,31 @@
* For text that will not change, use a {@link StaticLayout}.
*/
public abstract class Layout {
+ /** @hide */
+ @IntDef({BREAK_STRATEGY_SIMPLE, BREAK_STRATEGY_HIGH_QUALITY, BREAK_STRATEGY_BALANCED})
+ @Retention(RetentionPolicy.SOURCE)
+ public @interface BreakStrategy {}
+
+ /**
+ * Value for break strategy indicating simple line breaking. Automatic hyphens are not added
+ * (though soft hyphens are respected), and modifying text generally doesn't affect the layout
+ * before it (which yields a more consistent user experience when editing), but layout may not
+ * be the highest quality.
+ */
+ public static final int BREAK_STRATEGY_SIMPLE = 0;
+
+ /**
+ * Value for break strategy indicating high quality line breaking, including automatic
+ * hyphenation and doing whole-paragraph optimization of line breaks.
+ */
+ public static final int BREAK_STRATEGY_HIGH_QUALITY = 1;
+
+ /**
+ * Value for break strategy indicating balanced line breaking. The breaks are chosen to
+ * make all lines as close to the same length as possible, including automatic hyphenation.
+ */
+ public static final int BREAK_STRATEGY_BALANCED = 2;
+
private static final ParagraphStyle[] NO_PARA_SPANS =
ArrayUtils.emptyArray(ParagraphStyle.class);