android 开发技巧(9)--为文本添加发亮的效果

把一个界面做成类似于LED灯一样的效果，需要定义一个类，加载特殊字体。为了实现发光效果，需要实现TextView类中的public void setShadowLayer (float radius, float dx, float dy, int color)，也可以通过 XML 中的 android:shadowColor, android:shadowDx、

android:shadowDy 和 android:shadowRadius 属 性 使 用 这 种 效 果。修改 android:shadowDx 和 android:shadowDy 属性的值可以改

变阴影与文本之间的偏移。指定 android:shadowRadius 属性可以让

用户产生一种文本更亮的错觉



先将digital-7.ttf字体放在assets下的fonts文件夹下，自定义一个LedTextView继承自TextView

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);
}

}

public class Hack11Activity extends Activity {
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
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_hack11);
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);
}
}

activity_hack11.xml

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android" >

<boerpower.com.android50hacks.view.LedTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="@string/default_time"
android:textColor="#3300ff00"
android:textSize="80sp" />

<boerpower.com.android50hacks.view.LedTextView
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" />

</merge>

<string name="default_time">88:88:88</string>

字体下载