【收藏篇】Android 开发中常用的10种工具类
导语
Android开发中，收集一些常用的代码工具类是非常重要的。现在Android开发技术已经很成熟了，很多代码大牛已经写出了很多框架和工具类，我们现在应该要站在巨人的肩膀上做开发了。今天我把平时开发中收集最常用的 10 个工具类，分享给大家。以后开发中合理利用，对于在平时开发中的效率是非常有帮助的 。
1安装应用APK
// 安装应用APK
private void installApk(String apkFilePath) {
File apkfile = new File(apkFilePath);
if (!apkfile.exists()) {
return;
}
Intent i = new Intent(Intent.ACTION_VIEW);
i.setDataAndType(Uri.parse("file://" + apkfile.toString()), "application/vnd.android.package-archive");
startActivity(i);
}
}2MD5算法
public final static String MD5(String s) {
char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
try {
byte[] btInput = s.getBytes(); // 获得MD5摘要算法的 MessageDigest 对象
MessageDigest mdInst = MessageDigest.getInstance("MD5"); // 使用指定的字节更新摘要
mdInst.update(btInput); // 获得密文
byte[] md = mdInst.digest(); // 把密文转换成十六进制的字符串形式
int j = md.length;
char str[] = new char[j * 2];
int k = 0; //把字节转换成对应的字符串
for (int i = 0; i < j; i++) {
byte byte0 = md[i];
str[k++] = hexDigits[byte0 >>> 4 & 0xf];
str[k++] = hexDigits[byte0 & 0xf];
}
return new String(str);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}3判断现在是否有网络
private boolean NetWorkStatus() {
ConnectivityManager cwjManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); cwjManager.getActiveNetworkInfo();
boolean netSataus = true;
if (cwjManager.getActiveNetworkInfo() != null) { netSataus = cwjManager.getActiveNetworkInfo().isAvailable(); Toast.makeText(this, "网络已经打开", Toast.LENGTH_LONG).show(); }
else {
Builder b = new AlertDialog.Builder(this).setTitle("没有可用的网络")
.setMessage("是否对网络进行设置？");
b.setPositiveButton("是", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int whichButton) {
Intent mIntent = new Intent("/");
ComponentName comp = new ComponentName( "com.android.settings", "com.android.settings.WirelessSettings");
mIntent.setComponent(comp);
mIntent.setAction("android.intent.action.VIEW");
startActivityForResult(mIntent,0);
}
}).setNeutralButton("否", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
dialog.cancel();
}
}).show();
}
return netSataus;
}4获取设备屏幕的宽度高度密度
public class DisplayUtil {
/**
* 得到设备屏幕的宽度
*/
public static int getScreenWidth(Context context) {
return context.getResources().getDisplayMetrics().widthPixels;
} /**
* 得到设备屏幕的高度
*/
public static int getScreenHeight(Context context) {
return context.getResources().getDisplayMetrics().heightPixels;
} /**
* 得到设备的密度
*/
public static float getScreenDensity(Context context) {
return context.getResources().getDisplayMetrics().density;
}
}5dp、sp 转换为 px 的工具类
public class DisplayUtil {
/**
* 将px值转换为dip或dp值，保证尺寸大小不变
*/
public static int px2dip(Context context, float pxValue) { final float scale = context.getResources().getDisplayMetrics().density; return (int) (pxValue / scale + 0.5f);
} /**
* 将dip或dp值转换为px值，保证尺寸大小不变
*
* @param dipValue
* @param scale
* （DisplayMetrics类中属性density）
* @return
*/
public static int dip2px(Context context, float dipValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dipValue * scale + 0.5f);
} /**
* 将px值转换为sp值，保证文字大小不变
*
* @param pxValue
* @param fontScale
* （DisplayMetrics类中属性scaledDensity）
* @return
*/
public static int px2sp(Context context, float pxValue) {
final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
return (int) (pxValue / fontScale + 0.5f);
} /**
* 将sp值转换为px值，保证文字大小不变
*
* @param spValue
* @param fontScale
* （DisplayMetrics类中属性scaledDensity）
* @return
*/
public static int sp2px(Context context, float spValue) {
final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
return (int) (spValue * fontScale + 0.5f);
}
}6drawable转bitmap的工具类
/**
* drawable转bitmap
*
* @param drawable
* @return
*/private Bitmap drawableToBitamp(Drawable drawable) {
if (null == drawable) {
return null;
}if (drawable instanceof BitmapDrawable) {
BitmapDrawable bd = (BitmapDrawable) drawable;
return bd.getBitmap();
}
int w = drawable.getIntrinsicWidth();
int h = drawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, w, h);
drawable.draw(canvas);
return bitmap;
}7文章发布模仿朋友圈时间显示
public static String ChangeTime(Date time) {
String ftime = "";
Calendar cal = Calendar.getInstance(); // 判断是否是同一天
String curDate = dateFormater2.get().format(cal.getTime());
String paramDate = dateFormater2.get().format(time);
if (curDate.equals(paramDate)) {
int hour = (int) ((cal.getTimeInMillis() - time.getTime()) / 3600000);
if (hour == 0)
ftime = Math.max(
(cal.getTimeInMillis() - time.getTime()) / 60000, 1)
+ "分钟前";
else
ftime = hour + "小时前";
return ftime;
} long lt = time.getTime() / 86400000;
long ct = cal.getTimeInMillis() / 86400000;
int days = (int) (ct - lt);
if (days == 0) {
int hour = (int) ((cal.getTimeInMillis() - time.getTime()) / 3600000);
if (hour == 0)
ftime = Math.max( (cal.getTimeInMillis() - time.getTime()) / 60000, 1)
+ "分钟前";
else
ftime = hour + "小时前";
} else if (days == 1) {
ftime = "昨天";
} else if (days == 2) {
ftime = "前天 ";
} else if (days > 2 && days < 31) {
ftime = days + "天前";
} else if (days >= 31 && days <= 2 * 31) {
ftime = "一个月前";
} else if (days > 2 * 31 && days <= 3 * 31) {
ftime = "2个月前";
} else if (days > 3 * 31 && days <= 4 * 31) {
ftime = "3个月前";
} else {
ftime = dateFormater2.get().format(time);
} return ftime;
} public static String friendly_time(String sdate) {
Date time = null;
if (TimeZoneUtil.isInEasternEightZones())
time = toDate(sdate); else
time = TimeZoneUtil.transformTime(toDate(sdate),
TimeZone.getTimeZone("GMT+08"), TimeZone.getDefault());
if (time == null) {
return "Unknown";
}
String ftime = "";
Calendar cal = Calendar.getInstance(); // 判断是否是同一天
String curDate = dateFormater2.get().format(cal.getTime());
String paramDate = dateFormater2.get().format(time);
if (curDate.equals(paramDate)) {
int hour = (int) ((cal.getTimeInMillis() - time.getTime()) / 3600000);
if (hour == 0)
ftime = Math.max(
(cal.getTimeInMillis() - time.getTime()) / 60000, 1)
+ "分钟前";
else
ftime = hour + "小时前";
return ftime;
} long lt = time.getTime() / 86400000;
long ct = cal.getTimeInMillis() / 86400000;
int days = (int) (ct - lt);
if (days == 0) {
int hour = (int) ((cal.getTimeInMillis() - time.getTime()) / 3600000);
if (hour == 0)
ftime = Math.max(
(cal.getTimeInMillis() - time.getTime()) / 60000, 1)
+ "分钟前";
else
ftime = hour + "小时前";
} else if (days == 1) {
ftime = "昨天";
} else if (days == 2) {
ftime = "前天 ";
} else if (days > 2 && days < 31) {
ftime = days + "天前";
} else if (days >= 31 && days <= 2 * 31) {
ftime = "一个月前";
} else if (days > 2 * 31 && days <= 3 * 31) {
ftime = "2个月前";
} else if (days > 3 * 31 && days <= 4 * 31) {
ftime = "3个月前";
} else {
ftime = dateFormater2.get().format(time);
} return ftime;
}8时间格式转换工具类
public static String ConverToString(Date date) {
DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
return df.format(date);
}
public static String ConverToString2(Date date){
DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm");
return df.format(date);
}
public static String ConverToString3(Date date){
DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return df.format(date);
}9验证码倒计时工具类
public class TimeCount extends CountDownTimer {
private Button button; /**
* 到计时
* @param millisInFuture 到计时多久,毫秒
* @param countDownInterval 周期
* @param button 按钮
*/
public TimeCount(long millisInFuture, long countDownInterval,Button button) {
super(millisInFuture, countDownInterval);
this.button =button;
}
public TimeCount(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
}
@Override
public void onFinish() {// 计时完毕
button.setText("获取验证码");
button.setClickable(true);
button.setBackground(MyApplication.getContext().getResources().getDrawable(R.drawable.radius14));
}
@Override
public void onTick(long millisUntilFinished) {// 计时过程
button.setClickable(false);//防止重复点击
button.setText(millisUntilFinished / 1000 + "s后重试");
button.setBackground(MyApplication.getContext().getResources().getDrawable(R.drawable.radius_gray));
}
}10屏幕截图工具类
public class ScreenShot {
public static void shoot(Activity a, File filePath) {
if (filePath == null) {
return;
}
if (!filePath.getParentFile().exists()) {
filePath.getParentFile().mkdirs();
}
FileOutputStream fos = null;
try {
fos = new FileOutputStream(filePath);
if (null != fos) {
takeScreenShot(a).compress(Bitmap.CompressFormat.PNG, 100, fos);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} finally {
if (fos != null) {
try {
fos.flush();
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
} private static Bitmap takeScreenShot(Activity activity) {
View view = activity.getWindow().getDecorView();
view.setDrawingCacheEnabled(true);
view.buildDrawingCache();
Bitmap bitmap = view.getDrawingCache();
Rect frame = new Rect();
activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
int statusBarHeight = frame.top;
int width = activity.getWindowManager().getDefaultDisplay().getWidth();
int height = activity.getWindowManager().getDefaultDisplay()
.getHeight(); //去掉标题栏
Bitmap b = Bitmap.createBitmap(bitmap, 0, statusBarHeight, width,
height - statusBarHeight);
view.destroyDrawingCache(); return b;
}}总结
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原始发表：2017-10-08，如有侵权请联系 cloudcommunity@tencent.com 删除
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