你是誰的部落格

/* 
standard MessageDigest algorithms: 
MD5 
SHA-1 
SHA-256 
 */  
private String getCertificateFingerprint(Context mContext, String algorithm, String packageName) {  
    PackageManager pm = mContext.getPackageManager();  
    int flags = PackageManager.GET_SIGNATURES;  
    PackageInfo packageInfo = null;  
    try {  
        packageInfo = pm.getPackageInfo(packageName, flags);  
    } catch (PackageManager.NameNotFoundException e) {  
        e.printStackTrace();  
    }  
  
    if (packageInfo == null)  
        return null;  
  
    Signature[] signatures = packageInfo.signatures;  
    //此处我直接默认只有一个签名  
    byte[] cert = signatures[0].toByteArray();  
    InputStream input = new ByteArrayInputStream(cert);  
    CertificateFactory cf = null;  
    try {  
        cf = CertificateFactory.getInstance("X509");  
    } catch (CertificateException e) {  
        e.printStackTrace();  
    }  
  
    if (cf == null)  
        return null;  
  
    X509Certificate c = null;  
    try {  
        c = (X509Certificate) cf.generateCertificate(input);  
    } catch (CertificateException e) {  
        e.printStackTrace();  
    }  
  
    if (c==null)  
        return null;  
  
    String hexString = null;  
    try {  
        MessageDigest md = MessageDigest.getInstance(algorithm);  
        byte[] publicKey = md.digest(c.getEncoded());  
        hexString = byte2HexFormatted(publicKey);  
    } catch (NoSuchAlgorithmException e1) {  
        e1.printStackTrace();  
    } catch (CertificateEncodingException e) {  
        e.printStackTrace();  
    }  
    return hexString;  
}  
  
public static String byte2HexFormatted(byte[] arr) {  
    StringBuilder str = new StringBuilder(arr.length * 2);  
    for (int i = 0; i < arr.length; i++) {  
        String h = Integer.toHexString(arr[i]);  
        int l = h.length();  
        if (l == 1) h = "0" + h;  
        if (l > 2) h = h.substring(l - 2, l);  
        str.append(h.toUpperCase());  
        if (i < (arr.length - 1)) str.append(':');  
    }  
    return str.toString();  
}  

interface onScreenShotFinishedListener
{
  void onScreenShotFinished(@Nullable Bitmap pBitmap);
}

void screenShot(@NonNull Window window,@NonNull View pView, @NonNull onScreenShotFinishedListener pListener)
{
  Rect tRect = calcViewRect(pView);
  if (Build.VERSION.SDK_INT > Build.VERSION_CODES.O)
  {
    Bitmap tBitmap = Bitmap.createBitmap(tRect.width(), tRect.height(), Bitmap.Config.ARGB_8888, true);
    try
    {
      PixelCopy.request(window, tRect, tBitmap, new PixelCopy.OnPixelCopyFinishedListener()
      {
        @Override
        public void onPixelCopyFinished(int copyResult)
        {
          if (PixelCopy.SUCCESS == copyResult)
          {
            pListener.onScreenShotFinished(tBitmap);
          }
          else
          {
            pListener.onScreenShotFinished(null);
          }
        }
      }, new Handler(Looper.getMainLooper()));
    }
    catch (Exception e)
    {
      e.printStackTrace();
      pListener.onScreenShotFinished(null);
    }
  }
  else
  {
    pView.setDrawingCacheEnabled(true);
    try
    {
      Bitmap tBitmap = Bitmap.createBitmap(pView.getDrawingCache());
      pListener.onScreenShotFinished(tBitmap);
    }
    catch (Exception e)
    {
      e.printStackTrace();
      pListener.onScreenShotFinished(null);
    }
    finally
    {
      pView.setDrawingCacheEnabled(false);
    }
  }
}

private Rect calcViewRect(View pTargetView)
{
  int[] location = new int[2];
  pTargetView.getLocationOnScreen(location);
  Rect tRect = new Rect(location[0],
    location[1],
    location[0] + pTargetView.getWidth(),
    location[1] + pTargetView.getHeight());
  return tRect;
}

TextView.setTransformationMethod(new PersonalCapitalTransformationMethod(5, 12, '*'));

class PersonalCapitalTransformationMethod extends PasswordTransformationMethod
{
  private int m_Begin;
  private int m_End;
  private char m_Replacement;
  public PersonalCapitalTransformationMethod(int pBegin, int pEnd, char pReplacement)
  {
    super();
    m_Begin = pBegin;
    m_End = pEnd;
    m_Replacement = pReplacement;
  }

  @Override
  public CharSequence getTransformation(CharSequence pSource, View pView)
  {
    return new PersonalCapitalCharSequence(pSource);
  }

  private class PersonalCapitalCharSequence implements CharSequence
  {
    private CharSequence m_Source;

    public PersonalCapitalCharSequence(CharSequence pSource)
    {
      m_Source = pSource;
    }

public class ReconnectInterval
{
  private AtomicInteger m_AtomicCount = new AtomicInteger(0);
  private int m_Max = 12;
  private double A = Math.sqrt(5) / 5;
  private double B = (1 + Math.sqrt(5)) / 2;
  private double C = (1 - Math.sqrt(5)) / 2;

  long getInterval()
  {
    int nValue = m_AtomicCount.incrementAndGet();

    if (nValue / m_Max > 0)
    {
        nValue = m_Max;
    }
    long lFibonacci = fibonacci(nValue);
    return lFibonacci * 1000;
  }

  void reset()
  {
    m_AtomicCount.set(0);
  }

  long getRetryCount()
  { 
    return m_AtomicCount.get();
  }

double dbAngle = Math.abs(
  180 * Math.atan2((e1.getY() - e2.getY()), (e2.getX() - e1.getX())) / Math.PI);
if (dbAngle > 45 && dbAngle < 135){
  //TODO SOME THINGS
}
else
{
  //TODO SOME THINGS
}

StringBuilder tStringBuilder = new StringBuilder();
StackTraceElement[] tStackTraceElement = new Throwable().getStackTrace();
int nStacksLen = tStackTraceElement.length;
if (nStacksLen > 0)
{
  tStringBuilder.append("class: ").append(tStackTraceElement[1].getClassName())
    .append("; method: ").append(tStackTraceElement[1].getMethodName())
    .append("; number: ").append(tStackTraceElement[1].getLineNumber());
}

//執行緒池
Dispatcher dispatcher = new Dispatcher(
  new ThreadPoolExecutor(0, Integer.MAX_VALUE, 60, TimeUnit.SECONDS,
  new SynchronousQueue<Runnable>(), 
  Util.threadFactory("OkHttp Dispatcher", false)));

//最大的請求數量 def 64
dispatcher.setMaxRequests(64);

//主機同一個時間,最大的請求數量 def 5
dispatcher.setMaxRequestsPerHost(5);

//連線池
ConnectionPool connectionPool = new ConnectionPool(5, 5, TimeUnit.MINUTES);

OkHttpClient client = builder
  .dispatcher(dispatcher)
  .connectionPool(connectionPool)
  .connectTimeout(5, TimeUnit.SECONDS)
  .writeTimeout(5, TimeUnit.SECONDS)
  .readTimeout(5, TimeUnit.SECONDS)
  .followRedirects(true)
  .retryOnConnectionFailure(false)
  .build();

layout_behavior="com.google.android.material.bottomsheet.BottomSheetBehavior"
layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior"

RecyclerView 提供相當多種控制Scroll的方法
1.scrollBy(int x, int y)
2.scrollTo(int x, int y)
3.scrollToPosition(int position)
4.smoothScrollBy(int dx, int dy)
5.smoothScrollBy(int dx, int dy, Interpolator interpolator)
6.smoothScrollToPosition(int position)
其中ScrollToPosition與smoothScrollToPosition，
都只能讓指定的Position顯示在畫面上而具體位置在哪則無法控制。

若使用LinearLayoutManager的
scrollToPositionWithOffset(int position, int offset)
這個方法則解決了上面的問題其中若將offset設定為０則此position將置頂，
若為100則positionru將會停在距離上方100Pixel的位置。

AppBarLayout無法滑動時可透過設定DragCallback解決此問題

CoordinatorLayout.LayoutParams tParams = (CoordinatorLayout.LayoutParams) m_AppBarLayout.getLayoutParams();
AppBarLayout.Behavior tBehavior = new AppBarLayout.Behavior();
tBehavior.setDragCallback(new AppBarLayout.Behavior.DragCallback()
{
  @Override
  public boolean canDrag(@NonNull AppBarLayout appBarLayout)
  {
    return true;
  }
});
tParams.setBehavior(tBehavior);