Android很有用的代码片段
android中如何设置焦点在某一个指定的View上:
view.requestFocus();
大的滚动条设置：
listView.setFastScrollEnabled(true);
EditText光标在右边，输入内容从右往左：
android:gravity="center_vertical|right"
或者
editText.setGravity(Gravity.RIGHT);
EditText setText()之后光标会自动跑到第一个字符之前，手动设置光标的方法：
editText.setSelection(position);//position为int，指的是光标的位置，设置成EditText输入框中字符的长度，光标则为最后了
获得EditText中当前光标的位置的方法:
editText.getSelectionStart();
设置EditText是否有光标：
android:cursorVisible="false" //为false时选中了也没有光标
或editText.setCursorVisible(visible);
隐藏软键盘
((InputMethodManager)getSystemService(INPUT_METHOD_SERVICE)).hideSoftInputFromWindow(YourA ctivity.this.getCurrentFocus().getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
1：查看是否有存储卡插入
String status=Environment.getExternalStorageState();
if(status.equals(Enviroment.MEDIA_MOUNTED))
{
说明有SD卡插入
}
2：让某个Activity透明
OnCreate中不设Layout this.setTheme(R.style.Theme_Transparent);
以下是Theme_Transparent的定义（注意transparent_bg是一副透明的图片）
3：在屏幕元素中设置句柄
使用Activity.findViewById来取得屏幕上的元素的句柄. 使用该句柄您可以设置或获取任何该对象外露的值.
TextView msgTextView = (TextView)findViewById(R.id.msg);
msgTextView.setText(R.string.push_me);
4：发送短信
String body=”this is mms demo”;
Intent mmsintent = new Intent(Intent.ACTION_SENDTO, Uri.fromParts(”smsto”, number, null));
mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_BODY, body);
mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_COMPOSE_MODE, true);
mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_EXIT_ON_SENT, true);
startActivity(mmsintent);
5：发送彩信
StringBuilder sb = new StringBuilder();
sb.append(”file://”);
sb.append(fd.getAbsoluteFile());
Intent intent = new Intent(Intent.ACTION_SENDTO, Uri.fromParts(”mmsto”, number, null));
// Below extra datas are all optional.
intent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_SUBJECT, subject);
intent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_BODY, body);
intent.putExtra(Messaging.KEY_ACTION_SENDTO_CONTENT_URI, sb.toString());
intent.putExtra(Messaging.KEY_ACTION_SENDTO_COMPOSE_MODE, composeMode);
intent.putExtra(Messaging.KEY_ACTION_SENDTO_EXIT_ON_SENT, exitOnSent);
startActivity(intent);
6：发送Mail
mime = “img/jpg”;
shareIntent.setDataAndType(Uri.fromFile(fd), mime);
shareIntent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(fd));
shareIntent.putExtra(Intent.EXTRA_SUBJECT, subject);
shareIntent.putExtra(Intent.EXTRA_TEXT, body);
7：注册一个BroadcastReceiver
registerReceiver(mMasterResetReciever, new IntentFilter(”oms.action.MASTERRESET”));
private BroadcastReceiver mMasterResetReciever = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent){
String action = intent.getAction();
if(”oms.action.MASTERRESET”.equals(action)){
RecoverDefaultConfig();
}
}
};
8：定义ContentObserver，监听某个数据表
private ContentObserver mDownloadsObserver = new DownloadsChangeObserver(Downloads.CONTENT_URI);
private class DownloadsChangeObserver extends ContentObserver {
public DownloadsChangeObserver(Uri uri) {
super(new Handler());
}
@Override
public void onChange(boolean selfChange) {｝
}
9：获得 手机UA
public String getUserAgent()
{
String user_agent = ProductProperties.get(ProductProperties.USER_AGENT_KEY, null);
return user_agent;
}
10：清空手机上Cookie
CookieSyncManager.createInstance(getApplicationContext());
CookieManager.getInstance().removeAllCookie();
11：建立GPRS连接
//Dial the GPRS link.
private boolean openDataConnection() {
// Set up data connection.
DataConnection conn = DataConnection.getInstance();
if (connectMode == 0) {
ret = conn.openConnection(mContext, “cmwap”, “cmwap”, “cmwap”);
} else {
ret = conn.openConnection(mContext, “cmnet”, “”, “”);
}
}
12：PreferenceActivity 用法
public class Setting extends PreferenceActivity
｛
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings)；
}
｝
Setting.xml:
android:key=”seting2″
android:title=”@string/seting2″
android:summary=”@string/seting2″/>
android:key=”seting1″
android:title=”@string/seting1″
android:summaryOff=”@string/seting1summaryOff”
android:summaryOn=”@stringseting1summaryOff”/>
13：通过HttpClient从指定server获取数据
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet method = new HttpGet(“http://www.baidu.com/1.html”);
HttpResponse resp;
Reader reader = null;
try {
// AllClientPNames.TIMEOUT
HttpParams params = new BasicHttpParams();
params.setIntParameter(AllClientPNames.CONNECTION_TIMEOUT, 10000);
httpClient.setParams(params);
resp = httpClient.execute(method);
int status = resp.getStatusLine().getStatusCode();
if (status != HttpStatus.SC_OK) return false;
// HttpStatus.SC_OK;
return true;
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (reader != null) try {
reader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
14：显示toast
Toast.makeText(this._getApplicationContext(), R.string._item, Toast.LENGTH_SHORT).show();
获得当前屏幕宽高的方法.
Display display = getWindowManager().getDefaultDisplay(); Config.screenWidth = display.getWidth(); Config.screenHeight = display.getHeight();
1.处理listView中item之间的横线取消掉或者设置成别的：
getListView().setDivider(null);
getListView().setDividerHeight(0);
或者
in XML:
android:divider="@drawable/list_item_divider" android:dividerHeight="1dp"
也可以设置成颜色(e.g. #ff112233), 但是以前的老版本不行，这里也已用 9-patch or a image 代替
3.设置 soft keyboard 不可见
<activity android:label="@string/app_name" android:name=".MainActivity" android:windowSoftInputMode="stateHidden">