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@lucasr
Last active March 1, 2024 15:47
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Use StaticLayout's max lines support on ICS+
package org.lucasr.layoutsamples.canvas;
import android.os.Build;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextDirectionHeuristic;
import android.text.TextDirectionHeuristics;
import android.text.TextPaint;
import android.text.TextUtils.TruncateAt;
import android.util.Log;
import java.lang.reflect.Constructor;
public class StaticLayoutWithMaxLines {
private static final String LOGTAG = "StaticLayoutWithMaxLines";
private static final String TEXT_DIR_CLASS = "android.text.TextDirectionHeuristic";
private static final String TEXT_DIRS_CLASS = "android.text.TextDirectionHeuristics";
private static final String TEXT_DIR_FIRSTSTRONG_LTR = "FIRSTSTRONG_LTR";
private static boolean sInitialized;
private static Constructor<StaticLayout> sConstructor;
private static Object[] sConstructorArgs;
private static Object sTextDirection;
public static synchronized void ensureInitialized() {
if (sInitialized) {
return;
}
try {
final Class<?> textDirClass;
if (Build.VERSION.SDK_INT >= 18) {
textDirClass = TextDirectionHeuristic.class;
sTextDirection = TextDirectionHeuristics.FIRSTSTRONG_LTR;
} else {
final ClassLoader loader = StaticLayoutWithMaxLines.class.getClassLoader();
textDirClass = loader.loadClass(TEXT_DIR_CLASS);
final Class<?> textDirsClass = loader.loadClass(TEXT_DIRS_CLASS);
sTextDirection = textDirsClass.getField(TEXT_DIR_FIRSTSTRONG_LTR)
.get(textDirsClass);
}
final Class<?>[] signature = new Class[] {
CharSequence.class,
int.class,
int.class,
TextPaint.class,
int.class,
Alignment.class,
textDirClass,
float.class,
float.class,
boolean.class,
TruncateAt.class,
int.class,
int.class
};
// Make the StaticLayout constructor with max lines public
sConstructor = StaticLayout.class.getDeclaredConstructor(signature);
sConstructor.setAccessible(true);
sConstructorArgs = new Object[signature.length];
} catch (NoSuchMethodException e) {
Log.e(LOGTAG, "StaticLayout constructor with max lines not found.", e);
} catch (ClassNotFoundException e) {
Log.e(LOGTAG, "TextDirectionHeuristic class not found.", e);
} catch (NoSuchFieldException e) {
Log.e(LOGTAG, "TextDirectionHeuristics.FIRSTSTRONG_LTR not found.", e);
} catch (IllegalAccessException e) {
Log.e(LOGTAG, "TextDirectionHeuristics.FIRSTSTRONG_LTR not accessible.", e);
} finally {
sInitialized = true;
}
}
public static boolean isSupported() {
if (Build.VERSION.SDK_INT < 14) {
return false;
}
ensureInitialized();
return (sConstructor != null);
}
public static synchronized StaticLayout create(CharSequence source, int bufstart, int bufend,
TextPaint paint, int outerWidth, Alignment align,
float spacingMult, float spacingAdd,
boolean includePad, TruncateAt ellipsize,
int ellipsisWidth, int maxLines) {
ensureInitialized();
try {
sConstructorArgs[0] = source;
sConstructorArgs[1] = bufstart;
sConstructorArgs[2] = bufend;
sConstructorArgs[3] = paint;
sConstructorArgs[4] = outerWidth;
sConstructorArgs[5] = align;
sConstructorArgs[6] = sTextDirection;
sConstructorArgs[7] = spacingMult;
sConstructorArgs[8] = spacingAdd;
sConstructorArgs[9] = includePad;
sConstructorArgs[10] = ellipsize;
sConstructorArgs[11] = ellipsisWidth;
sConstructorArgs[12] = maxLines;
return sConstructor.newInstance(sConstructorArgs);
} catch (Exception e) {
throw new IllegalStateException("Error creating StaticLayout with max lines: " + e);
}
}
}
@liganisme
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well done!

@stanmots
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Thanks, this is just what I was looking for.

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