<?xml version="1.0" encoding="utf-8"?> <level-list xmlns:android="http://schemas.android.com/apk/res/android"> <item android:maxLevel="0" android:drawable="@android:color/transparent" /> <item android:maxLevel="1" android:drawable="@drawable/image_1" /> <item android:maxLevel="2" android:drawable="@drawable/image_2" /> <item android:maxLevel="3" android:drawable="@drawable/image_3" /> </level-list> 

 new CountdownTimer(30000, 1000) {public void onTick(long millisUntilFinished) {mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);}public void onFinish() {mTextField.setText("done!");}}.start();

package cn.demo;import android.app.Activity;
import android.os.Bundle;
import android.content.Intent;
import android.os.CountDownTimer;
import android.widget.TextView;
import android.widget.Toast;
public class NewActivity extends Activity {private MyCount mc;private TextView tv;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.main);tv = (TextView)findViewById(R.id.show);mc = new MyCount(30000, 1000);mc.start();}//end func/*定义一个倒计时的内部类*/class MyCount extends CountDownTimer {   public MyCount(long millisInFuture, long countDownInterval) {   super(millisInFuture, countDownInterval);   }   @Override   public void onFinish() {   tv.setText("finish");      }   @Override   public void onTick(long millisUntilFinished) {   tv.setText("请等待30秒(" + millisUntilFinished / 1000 + ")...");   Toast.makeText(NewActivity.this, millisUntilFinished / 1000 + "", Toast.LENGTH_LONG).show();//toast有显示时间延迟
        }  }
}

<?xml version="1.0" encoding="utf-8"?>
<resources><drawable name="red">#f00</drawable><drawable name="green">#0f0</drawable><drawable name="gray">#ccc</drawable>
</resources>

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android"><item android:state_window_focused="false" android:state_enabled="true"android:drawable="@drawable/btn_test_normal" /><item android:state_enabled="false" android:drawable="@drawable/btn_test_normal" /><item android:state_pressed="true" android:drawable="@drawable/btn_test_press" /><item android:state_focused="true"  android:drawable="@drawable/btn_test_normal" />
</selector>

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android"><item android:state_focused="false" android:state_enabled="true" android:state_pressed="false"android:color="@drawable/red" /><item android:state_enabled="false" android:color="@drawable/gray" /><item android:state_pressed="true" android:color="@drawable/green" /><item android:state_focused="true"  android:color="@drawable/red" />
</selector>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="fill_parent"android:layout_height="fill_parent"android:background="@android:color/white"><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="按下文字会变效果"android:textColor="@drawable/btn_color"android:background="@drawable/btn_bg"/><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="按钮被禁用"android:enabled="false"android:textColor="@drawable/btn_color"android:background="@drawable/btn_bg"/></LinearLayout>

MyGallery extends Gallery{int lastPosition;@Overrideprotected int getChildDrawingOrder(int childCount, int i) {int mFirstPosition = getFirstVisiblePosition();int mSelectedPosition = getSelectedItemPosition();   int selectedIndex = mSelectedPosition - mFirstPosition;if(i == 0)lastPosition = 0;int ret = 0;if (selectedIndex < 0) return i;        if (i == childCount - 1) {ret = selectedIndex;} else if (i >= selectedIndex) {lastPosition++;ret = childCount - lastPosition;} else {ret = i;}return ret;}}

EditText 和TextView一样，也可以进行图文混排。所不同的是，TextView只用于显示图文混排效果，而EditText不仅可显示， 也可混合输入文字和图像，让我们先回顾一下图5.2所示的QQ聊天输入框，在输入框中可以同时输入文字和表情图像。实际上，这种效果在Android SDK中只需要几行代码就可以实现。为了使读者更有学习的冲动，先来欣赏一下即将实现的效果，如图5.16所示。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical" android:layout_width="fill_parent"android:layout_height="fill_parent"><EditText android:id="@+id/edittext" android:layout_width="fill_parent"android:layout_height="wrap_content" android:lines="3" android:gravity="left|top"/><Button android:layout_width="wrap_content"android:layout_height="wrap_content" android:text="随机插入表情"android:onClick="onClick_RandomFace" android:layout_marginTop="10dp" />
</LinearLayout>

public void onClick_RandomFace(View view)
{//  随机产生1至9的整数int randomId = 1 + new Random().nextInt(9);try{//  根据随机产生的1至9的整数从R.drawable类中获得相应资源ID（静态变量）的Field对象Field field = R.drawable.class.getDeclaredField("face" + randomId);//  获得资源ID的值，也就是静态变量的值int resourceId = Integer.parseInt(field.get(null).toString());//  根据资源ID获得资源图像的Bitmap对象Bitmap bitmap = BitmapFactory.decodeResource(getResources(), resourceId);//  根据Bitmap对象创建ImageSpan对象ImageSpan imageSpan = new ImageSpan(this, bitmap);//  创建一个SpannableString对象，以便插入用ImageSpan对象封装的图像SpannableString spannableString = new SpannableString("face");//  用ImageSpan对象替换facespannableString.setSpan(imageSpan, 0, 4, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);//  将随机获得的图像追加到EditText控件的最后
        edittext.append(spannableString);}catch (Exception e){}
}

//声明：
private int ImageCnt = 0;
//实例化：
imgV1 = (ImageView)findViewById(R.id.imageView1);
//设置图像：
imgV1.setImageResource(R.drawable.imgview1);
//设置单击监听器：
imgV1.setOnClickListener(new OnClickListener(){@Override
public void onClick(View v) {// TODO Auto-generated method stubImageCnt = ImageCnt==0?1:0;imgV1.setImageResource(R.drawable.imgview1+ImageCnt);}});

privatevoid galleryAddPic(){    Intent mediaScanIntent =newIntent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);    File f =newFile(mCurrentPhotoPath);    Uri contentUri =Uri.fromFile(f);    mediaScanIntent.setData(contentUri);    this.sendBroadcast(mediaScanIntent);}

    final TelephonyManager tm = (TelephonyManager) getBaseContext().getSystemService(Context.TELEPHONY_SERVICE);final String tmDevice, tmSerial, androidId;tmDevice = "" + tm.getDeviceId();tmSerial = "" + tm.getSimSerialNumber();androidId = "" + android.provider.Settings.Secure.getString(getContentResolver(), android.provider.Settings.Secure.ANDROID_ID);UUID deviceUuid = new UUID(androidId.hashCode(), ((long)tmDevice.hashCode() << 32) | tmSerial.hashCode());String deviceId = deviceUuid.toString();

public class Installation {private static String sID = null;private static final String INSTALLATION = "INSTALLATION";public synchronized static String id(Context context) {if (sID == null) {  File installation = new File(context.getFilesDir(), INSTALLATION);try {if (!installation.exists())writeInstallationFile(installation);sID = readInstallationFile(installation);} catch (Exception e) {throw new RuntimeException(e);}}return sID;}private static String readInstallationFile(File installation) throws IOException {RandomAccessFile f = new RandomAccessFile(installation, "r");byte[] bytes = new byte[(int) f.length()];f.readFully(bytes);f.close();return new String(bytes);}private static void writeInstallationFile(File installation) throws IOException {FileOutputStream out = new FileOutputStream(installation);String id = UUID.randomUUID().toString();out.write(id.getBytes());out.close();}
}