Android实现LED发光字效果

public class LedTextView extends TextView {

 private static final String FONTS_FOLDER = "fonts";
 private static final String FONT_DIGITAL_7 = FONTS_FOLDER
  + File.separator + "digital-7.ttf";

 public LedTextView(Context context) {
 super(context);
 init(context);
 }

 public LedTextView(Context context, AttributeSet attrs) {
 super(context, attrs);
 init(context);
 }

 public LedTextView(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 init(context);
 }

 private void init(Context context) {
 AssetManager assets = context.getAssets();
 final Typeface font = Typeface.createFromAsset(assets,
  FONT_DIGITAL_7);
 setTypeface(font);
 }

}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:background="#000000"
 android:layout_height="match_parent">

 <com.eloancn.ledtextview.LedTextView
  android:layout_centerInParent="true"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="center"
  android:text="88:88:88"
  android:textColor="#3300ff00"
  android:textSize="80sp" />

 <com.eloancn.ledtextview.LedTextView
  android:layout_centerInParent="true"
  android:id="@+id/main_clock_time"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="center"
  android:shadowColor="#00ff00"
  android:shadowDx="0"
  android:shadowDy="0"
  android:shadowRadius="10"
  android:textColor="#00ff00"
  android:textSize="80sp" />

</RelativeLayout>

android:shadowColor="#00ff00"
android:shadowDx="0"
android:shadowDy="0"
android:shadowRadius="10"

public class MainActivity extends AppCompatActivity {
 private static final String DATE_FORMAT = "%02d:%02d:%02d";
 private static final int REFRESH_DELAY = 500;

 private final Handler mHandler = new Handler();
 private final Runnable mTimeRefresher = new Runnable() {
  @Override
  public void run() {
   final Date d = new Date();
   mTextView.setText(String.format(DATE_FORMAT, d.getHours(),
     d.getMinutes(), d.getSeconds()));
   mHandler.postDelayed(this, REFRESH_DELAY);
  }
 };

 private TextView mTextView;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  mTextView = (TextView) findViewById(R.id.main_clock_time);
 }

 @Override
 protected void onResume() {
  super.onResume();
  mHandler.post(mTimeRefresher);
 }

 @Override
 protected void onStop() {
  super.onStop();
  mHandler.removeCallbacks(mTimeRefresher);
 }
}