android开发常用代码(经常更新)

android开发中我们需要一些代码来使我们的界面更美观，控件更漂亮。

除了android开发，还有程序中经常用到的东西。

比如圆角的button啊，view的布局啊等等。

下面是一些常用的代码

1.圆角button

android开发中我们需要一些代码来使我们的界面更美观，控件更漂亮。

比如圆角的button啊，view的布局啊等等。比如圆角的button啊，view的布局啊等等。

下面是一些常用的代码下面是一些常用的代码

1.圆角button1.圆角button

<?xml version="1.0" encoding="UTF-8"?>
<shape
xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<!-- 填充的颜色 -->
<solid android:color="#3881fe" />
<!-- 设置按钮的四个角为弧形 -->
<!-- android:radius 弧形的半径 -->
<corners android:radius="5dip" />

<!-- padding：Button里面的文字与Button边界的间隔 -->
<padding
android:left="10dp"
android:top="10dp"
android:right="10dp"
android:bottom="10dp"
/>
</shape>

2.canvas画圆角矩形

RectF backRect = new RectF(1, 0, (float) (getWidth() - 1), getHeight() - 4.5f);
canvas.drawRoundRect(backRect, 7, 7, mPaint);

3.popupWindow使用

public void showPopupWindow(Context context, View parent) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final View view = inflater.inflate(R.layout.popwindow, null, false);
int screenWidth = getResources().getDisplayMetrics().widthPixels;
final PopupWindow pw = new PopupWindow(view, screenWidth - 50, 300,
true);
pw.setFocusable(true);
pw.setTouchable(true);
//点击popupwindow以外区域消失
pw.setBackgroundDrawable(new BitmapDrawable());
pw.setOutsideTouchable(true);

pw.showAtLocation(MainActivity.this.findViewById(R.id.main),
Gravity.BOTTOM | Gravity.CENTER_HORIZONTAL, 0, 0);
// 显示popupWindow对话框
}

4.LayoutInflater 的使用

LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final View view = inflater.inflate(R.layout.xxxx, null, false);

5.生成圆角图片

public static Bitmap GetRoundedCornerBitmap(Bitmap bitmap) {
try {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(),
bitmap.getHeight());
final RectF rectF = new RectF(new Rect(0, 0, bitmap.getWidth(),
bitmap.getHeight()));
final float roundPx = 14;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.BLACK);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));

final Rect src = new Rect(0, 0, bitmap.getWidth(),
bitmap.getHeight());

canvas.drawBitmap(bitmap, src, rect, paint);
return output;
} catch (Exception e) {
return bitmap;
}
}

6.得到SD路径

public static String getSDPath() {
File SDPath = null;
boolean isSDExist = Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED);
if (isSDExist == true) {
SDPath = Environment.getExternalStorageDirectory();
}
return SDPath.toString();
}

7.将string写到文件末尾

/**
* 将字符串写到文件末尾
* @param txt 原始字符串
* @param fileName 带路径的文件名
* @return true 写入成功
*/
public static boolean stringToFileEnd(String txt, String fileName) {
File file = new File(fileName);
if (file.exists()) {
try {
FileOutputStream outputStream = new FileOutputStream(fileName,
true);
outputStream.write(txt.getBytes());
outputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
return true;
} else {
return false;
}
}

8.得到手机屏幕高度宽度以及scale

scale = getResources().getDisplayMetrics().density;
screenHeight = getResources().getDisplayMetrics().heightPixels;
screenWidth = getResources().getDisplayMetrics().widthPixels;

9.onMeasure常用方法 获取当前控件高度和宽度等等

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
height = screenHeight / 4;
width = measureWidth(widthMeasureSpec);
setMeasuredDimension(width, height);
}

private int measureHeight(int measureSpec) {

int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);

// Default size if no limits are specified.

int result = 500;
if (specMode == MeasureSpec.AT_MOST) {

// Calculate the ideal size of your
// control within this maximum size.
// If your control fills the available
// space return the outer bound.

result = specSize;
} else if (specMode == MeasureSpec.EXACTLY) {

// If your control can fit within these bounds return that value.
result = specSize;
}

return result;
}

private int measureWidth(int measureSpec) {
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);

// Default size if no limits are specified.
int result = 500;
if (specMode == MeasureSpec.AT_MOST) {
// Calculate the ideal size of your control
// within this maximum size.
// If your control fills the available space
// return the outer bound.
result = specSize;
}

else if (specMode == MeasureSpec.EXACTLY) {
// If your control can fit within these bounds return that value.

result = specSize;
}

return result;
}

10.bitmap的缩放

/**
* 按照指定长宽压缩
*
* @param srcBitmap
* @param newWidth
* @param newHeight
* @return
*/
public static Bitmap bitmapZoomBySize(Bitmap srcBitmap, int newWidth,
int newHeight) {
int srcWidth = srcBitmap.getWidth();
int srcHeight = srcBitmap.getHeight();

float scaleWidth = ((float) newWidth) / srcWidth;
float scaleHeight = ((float) newHeight) / srcHeight;

return bitmapZoomByScale(srcBitmap, scaleWidth, scaleHeight);
}

/**
* 使用长宽缩放比缩放
*
* @param srcBitmap
* @param scaleWidth
* @param scaleHeight
* @return
*/
public static Bitmap bitmapZoomByScale(Bitmap srcBitmap, float scaleWidth,
float scaleHeight) {
int srcWidth = srcBitmap.getWidth();
int srcHeight = srcBitmap.getHeight();
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
Bitmap resizedBitmap = Bitmap.createBitmap(srcBitmap, 0, 0, srcWidth,
srcHeight, matrix, true);
if (resizedBitmap != null) {
return resizedBitmap;
} else {

return srcBitmap;
}
}

11.文件读写相关操作

//判断文件是否存在
public boolean isFileExits(String fileName) {
File file = new File(SDPath + fileName);
return file.exists();
}

//新建文件夹

public void makeDir(String dirName)
{
File file = new File(SDPath + dirName);
if (!file.exists())
file.mkdir();
}

//获得文件数量
public int getNumOfFiles(String dir)
{
File file = new File(SDPath + dir);
File[] numFile = file.listFiles();
return numFile.length;
}

//删除一个文件

<span style="white-space:pre">	</span>public boolean deleteFile(String fileName)
{
File file = new File(SDPath + fileName);
if (file.exists())
{
System.out.println("file name is  " + file.getName());
try {
file.delete();
} catch (Exception e) {
e.printStackTrace();
}
return true;
}
else {
return false;
}
}
//读取一个文件
public String readFromFile(String fileName)
{
String res = "";

try {

FileInputStream inputStream = new FileInputStream(SDPath + fileName);
int len = inputStream.available();
byte buffer[] = new byte[len];
inputStream.read(buffer);
res = EncodingUtils.getString(buffer, "UTF-8");
inputStream.close();

} catch (Exception e) {
e.printStackTrace();
}
System.out.println("res ----->" + res);
return res;
}
//将字符串写到文件末尾
public boolean stringToFileEnd(String txt,String fileName)
{
File file = new File(SDPath + fileName);
if (file.exists())
{
try {
FileOutputStream outputStream = new FileOutputStream(SDPath + fileName,true);
outputStream.write(txt.getBytes());
outputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
return true;
}
else {
return false;
}
}
//将字符串从文件头部开始写
public boolean stringToFile(String txtString,String fileName)
{
File file = new File(SDPath + fileName);
if (file.exists())
{
try {
FileOutputStream outputStream = new FileOutputStream(SDPath + fileName);
outputStream.write(txtString.getBytes());
outputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
return true;
}
else {
return false;
}
}
//删除文件
public File createFile(String fileName)
{
File file = new File(SDPath + fileName);
try {
file.createNewFile();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return file;
}

返回事件捕捉

public void onBackPressed() {
// TODO Auto-generated method stub
System.out.println("hehehehhehehehhe");
super.onBackPressed();
}

获取当前时间:

Time t=new Time("GMT+8"); // or Time t=new Time("GMT+8"); 加上Time Zone资料。
t.setToNow(); // 取得系统时间。
int year = t.year;
int month = t.month;
int date = t.monthDay;
int hour = t.hour; // 0-23
int minute = t.minute;
int second = t.second;

唯一不足的是月份少一月，小时得加8

22.获取星期几

public class DateString {
private static String mYear;
private static String mMonth;
private static String mDay;
private static String mWay;

public static String StringDate(){
final Calendar c = Calendar.getInstance();
c.setTimeZone(TimeZone.getTimeZone("GMT+8:00"));
mYear = String.valueOf(c.get(Calendar.YEAR)); // 获取当前年份
mMonth = String.valueOf(c.get(Calendar.MONTH) + 1);// 获取当前月份
mDay = String.valueOf(c.get(Calendar.DAY_OF_MONTH));// 获取当前月份的日期号码
mWay = String.valueOf(c.get(Calendar.DAY_OF_WEEK));
if("1".equals(mWay)){
mWay ="SUN";
}else if("2".equals(mWay)){
mWay ="MON";
}else if("3".equals(mWay)){
mWay ="TUE";
}else if("4".equals(mWay)){
mWay ="WED";
}else if("5".equals(mWay)){
mWay ="THU";
}else if("6".equals(mWay)){
mWay ="FRI";
}else if("7".equals(mWay)){
mWay ="SAT";
}
return mYear + "年" + mMonth + "月" + mDay+"日"+"/星期"+mWay;
}

}

22.判断当前是否联网

public boolean inNetwork() {
ConnectivityManager cManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo info = cManager.getActiveNetworkInfo();
if (info != null && info.isAvailable()) {
// do something
// 能联网
return true;
} else {
// do something
// 不能联网
return false;
}
}

23.listview一些常用属性设置

去掉item分割线
android:divider="@null"
去掉顶部和底部边缘模糊
android:overScrollMode="never"
去掉滑动栏
android:scrollbars="none"

hashmap遍历

public static void printHash(HashMap<String, String> hashMap) {
Iterator iter = hashMap.entrySet().iterator();
while (iter.hasNext()) {
Map.Entry entry = (Map.Entry) iter.next();
Object key = entry.getKey();
Object val = entry.getValue();
System.out.println("key = " + key + " val = " + val);
}
}

解析json字符串

private static Map<String, String> parseJSONString(String JSONString)
throws JSONException {
Map<String, String> resultMap = new HashMap<String, String>();
JSONArray jsonArray = new JSONArray();
try {
// 直接把JSON字符串转化为一个JSONObject对象
JSONObject person = new JSONObject(JSONString);
System.out.println("the info is "
+ person.getJSONArray("infoBaseTime").toString());
jsonArray = person.getJSONArray("infoBaseTime");
} catch (JSONException e) {
e.printStackTrace();
}

for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
Map<String, String> map = new HashMap<String, String>();
for (Iterator<?> iter = jsonObject.keys(); iter.hasNext();) {
String key = (String) iter.next();
String value = jsonObject.get(key).toString();
resultMap.put(key, value);
System.out.println("key is " + key + " value is " + value);
}
// rsList.add(map);
}
printHash(resultMap);
return resultMap;
}

http发起网络请求

/**
* 想数据库写入手机参数
*
* @param IMEI
*            手机的IMEI
* @param basetime
*            手机滑动基数
* @param deviceID
*            手机设备号
* @throws IOException
*/

public static void PostBaseTime(String IMEI, float basetime, String deviceID)
throws IOException {

String responseRes = "";
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(HTTP_POST_BASETIME);
List<BasicNameValuePair> formparams = new ArrayList<BasicNameValuePair>();
formparams.add(new BasicNameValuePair("baseTime", basetime + ""));
formparams.add(new BasicNameValuePair("IMEI", IMEI));
formparams.add(new BasicNameValuePair("deviceID", deviceID));
UrlEncodedFormEntity uefEntity = new UrlEncodedFormEntity(formparams,
HTTP.UTF_8);
httpPost.setEntity(uefEntity);
HttpResponse response = (HttpResponse) httpClient.execute(httpPost);
if (response.getStatusLine().getStatusCode() == 200) {
responseRes = EntityUtils
.toString(response.getEntity(), HTTP.UTF_8);
System.out.println("the res is " + responseRes);
}
}

得到手机一些参数，屏幕大小等等

screenWidth = wm.getDefaultDisplay().getWidth();
screenheight = wm.getDefaultDisplay().getHeight();
System.out.println("screen width is " + screenWidth
+ " screen height is " + screenheight);
scale = getActivity().getResources().getDisplayMetrics().density;
topHeight = (int) (scale * 50 + 0.5f);
bottomHeight = (int) (scale * 55 + 0.5f);
notiHeight = Resources.getSystem().getDimensionPixelSize(
Resources.getSystem().getIdentifier("status_bar_height",
"dimen", "android"));