Android代码片段（持续更新）
调用系统邮件发送页面
String[] emailReceiver = {"xxxxx@yy.com"};
Intent email = new Intent(Intent.ACTION_SEND);
// email.setType("text/plain");
// email.setType("plain/text");
email.putExtra(Intent.EXTRA_EMAIL, emailReceiver);
email.putExtra(Intent.EXTRA_SUBJECT, "邮件标题");
email.putExtra(Intent.EXTRA_TEXT, "邮件内容啊， 有木有");
// startActivity(email);
// startActivity(Intent.createChooser(email, "请选择邮件发送软件"));
// Uri uri = Uri.parse("/sdcard/1.txt");//提示文件太大，无法附加
Uri uri = Uri.parse("file:///sdcard/1.txt");
email.putExtra(Intent.EXTRA_STREAM, uri);
// email.setType("audio/mp3");
//适用于任何类型的附件
email.setType("message/rfc882");
startActivity(email);
禁止横竖屏切换
传送门：http://guoyiqi.iteye.com/blog/1432166
//如：放到所有Activity基类中，即可禁止整个程序所有的重力感应 setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_NOSENSOR);
上面设置对于有物理键盘的机型（如摩托里程碑），在物理键盘拉出或隐藏时，其系统内部横竖方向切换，Activity仍然会翻转，此时可设置竖屏显示：
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
设置控件的坐标/大小等相关属性：
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) this
.getLayoutParams();//RelativeLayout为当前控件所在布局文件的布局方式
params.topMargin = params.topMargin
+ this.mSpecialViewheight;//可设置坐标，宽高等属性(吐槽：获取属性一般都是getXXX(),get半天出不来...原来是直接public的)
this.setLayoutParams(params);
在OnCreate()方法中获取控件的高度和宽度，需要使用的一个观察者(否则得到的height, paddingTop等数据为0，因onCreate()执行时，控件还未加载完成)
ViewTreeObserver vto = imageview.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
// 此句若不执行，不影响控件宽高的获取结果，但是当前的onGlobalLayout()会执行多次,执行此句，当前方法只会执行一次
imageview.getViewTreeObserver().removeGlobalOnLayoutListener(
this);
Log.i("TAG", imageview.getMeasuredHeight()
+ " -- - " + imageview.getHeight());
}
});
自定义Notification:
/**
*
* 方法名称：customNotification
* 作者：PiaoXingguo
* 方法描述：创建自定义格式的Notification(其实只需模仿notification.setLatestEventInfo(...)方法的源码即可)
* 输入参数：@param context
* 返回类型：void
* 备注：
*/
private void customNotification(Context context) {
final NotificationManager nManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
Notification notification = new Notification(R.drawable.notification_icon, "custom", System.currentTimeMillis());
//R.layout.custom_notification 为自定义的xml布局文件,一个ImageView和两个TextView
RemoteViews contentView = new RemoteViews(context.getPackageName(), R.layout.custom_notification);
contentView.setTextViewText(R.id.text, "custom text!");
contentView.setImageViewResource(R.id.image, R.drawable.icon);
contentView.setTextViewText(R.id.title, "custom title!");
notification.contentView = contentView;
Intent intent = new Intent(context, TimeActivity.class);
PendingIntent pi = PendingIntent.getActivity(context, 0, intent, 0);
notification.contentIntent = pi;
notification.flags = Notification.FLAG_AUTO_CANCEL;//设置标记
//1为id, 若要更新此Notification,需要用到
nManager.notify(1, notification);
}
判断当前应用是否是最上层的应用：
public static boolean isTopApp(Context context) {
ActivityManager activityManager = (ActivityManager) context
.getSystemService(ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> tasks = activityManager
.getRunningTasks(5);
if (tasks == null || tasks.isEmpty()) {
return false;
}
RunningTaskInfo task = tasks.get(0);
String taskPackageName = task.topActivity.getPackageName();// task任务的package包名
System.out.println(taskPackageName);
// System.out.println(task.topActivity.getClassName());
// System.out.println(task.baseActivity.getClassName());
return context.getPackageName().equals(taskPackageName);
}
本机IP地址：
Enumeration<NetworkInterface> networkInfo = NetworkInterface
.getNetworkInterfaces();
while (networkInfo.hasMoreElements())
{
NetworkInterface intf = networkInfo.nextElement();
Enumeration<InetAddress> intfAddress = intf
.getInetAddresses();
while (intfAddress.hasMoreElements())
{
InetAddress inetAddress = intfAddress.nextElement();
if (!inetAddress.isLoopbackAddress())
{
ip = inetAddress.getHostAddress().toString();
}
}
}
屏幕分辨率及其相关属性：
DisplayMetrics dm = new DisplayMetrics();
activity.getWindowManager().getDefaultDisplay().getMetrics(dm);
System.out.println(dm.widthPixels + " - " + dm.heightPixels);
第二种方式获取DipalyMetrics对象（!= 上一种方式获取的对象 ）
DisplayMetrics dm = activity.getResources().getDisplayMetrics();
更直接的：
//WindowManager windowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE); 宽度：this.getWindowManager().getDefaultDisplay().getWidth();
Activity页面切换效果:
new Handler().postDelayed(new Runnable() {
@Override
public void run()
{
Intent intent = new Intent(TransitionActivity.this, DeviceActivity.class);
startActivity(intent);
finish();
//页面切换 -- 淡入淡出效果
overridePendingTransition(android.R.anim.fade_in, android.R.anim.fade_out);
// overridePendingTransition(R.anim.zoomin, R.anim.zoomout);
}
}, 5000);
