Question

我正在为Android平板电脑开发Android App开发。我需要在我的Application中实现签名捕获。任何人都可以建议实现它的最佳选择/方式。

由于

Answer 1

以下是询问此人姓名及其签名的示例程序。该程序使用画布视图来获取签名，然后将其另存为.png Image。

<强> CaptureSignatureActivity.java

public class CaptureSignatureActivity extends Activity {

public static final int SIGNATURE_ACTIVITY = 1;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    Button getSignature = (Button) findViewById(R.id.signature);
    getSignature.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            Intent intent = new Intent(CaptureSignatureActivity.this, CaptureSignature.class); 
            startActivityForResult(intent,SIGNATURE_ACTIVITY);
        }
    });
}

protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
    switch(requestCode) {
    case SIGNATURE_ACTIVITY: 
        if (resultCode == RESULT_OK) {

            Bundle bundle = data.getExtras();
            String status  = bundle.getString("status");
            if(status.equalsIgnoreCase("done")){
                Toast toast = Toast.makeText(this, "Signature capture successful!", Toast.LENGTH_SHORT);
                toast.setGravity(Gravity.TOP, 105, 50);
                toast.show();
            }
        }
        break;
    }

}

}

<强> CaptureSignature.java

public class CaptureSignature extends Activity { 

LinearLayout mContent;
signature mSignature;
Button mClear, mGetSign, mCancel;
public static String tempDir;
public int count = 1;
public String current = null;
private Bitmap mBitmap;
View mView;
File mypath;

private String uniqueId;
private EditText yourName;

@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.signature);

    tempDir = Environment.getExternalStorageDirectory() + "/" + getResources().getString(R.string.external_dir) + "/";
    ContextWrapper cw = new ContextWrapper(getApplicationContext());
    File directory = cw.getDir(getResources().getString(R.string.external_dir), Context.MODE_PRIVATE);

    prepareDirectory();
    uniqueId = getTodaysDate() + "_" + getCurrentTime() + "_" + Math.random();
    current = uniqueId + ".png";
    mypath= new File(directory,current);


    mContent = (LinearLayout) findViewById(R.id.linearLayout);
    mSignature = new signature(this, null);
    mSignature.setBackgroundColor(Color.WHITE);
    mContent.addView(mSignature, LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
    mClear = (Button)findViewById(R.id.clear);
    mGetSign = (Button)findViewById(R.id.getsign);
    mGetSign.setEnabled(false);
    mCancel = (Button)findViewById(R.id.cancel);
    mView = mContent;

    yourName = (EditText) findViewById(R.id.yourName);

    mClear.setOnClickListener(new OnClickListener() 
    {        
        public void onClick(View v) 
        {
            Log.v("log_tag", "Panel Cleared");
            mSignature.clear();
            mGetSign.setEnabled(false);
        }
    });

    mGetSign.setOnClickListener(new OnClickListener() 
    {        
        public void onClick(View v) 
        {
            Log.v("log_tag", "Panel Saved");
            boolean error = captureSignature();
            if(!error){
                mView.setDrawingCacheEnabled(true);
                mSignature.save(mView);
                Bundle b = new Bundle();
                b.putString("status", "done");
                Intent intent = new Intent();
                intent.putExtras(b);
                setResult(RESULT_OK,intent);   
                finish();
            }
        }
    });

    mCancel.setOnClickListener(new OnClickListener() 
    {        
        public void onClick(View v) 
        {
            Log.v("log_tag", "Panel Canceled");
            Bundle b = new Bundle();
            b.putString("status", "cancel");
            Intent intent = new Intent();
            intent.putExtras(b);
            setResult(RESULT_OK,intent);  
            finish();
        }
    });

}

@Override
protected void onDestroy() {
    Log.w("GetSignature", "onDestory");
    super.onDestroy();
}

private boolean captureSignature() {

    boolean error = false;
    String errorMessage = "";


    if(yourName.getText().toString().equalsIgnoreCase("")){
        errorMessage = errorMessage + "Please enter your Name\n";
        error = true;
    }   

    if(error){
        Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT);
        toast.setGravity(Gravity.TOP, 105, 50);
        toast.show();
    }

    return error;
}

private String getTodaysDate() { 

    final Calendar c = Calendar.getInstance();
    int todaysDate =     (c.get(Calendar.YEAR) * 10000) + 
    ((c.get(Calendar.MONTH) + 1) * 100) + 
    (c.get(Calendar.DAY_OF_MONTH));
    Log.w("DATE:",String.valueOf(todaysDate));
    return(String.valueOf(todaysDate));

}

private String getCurrentTime() {

    final Calendar c = Calendar.getInstance();
    int currentTime =     (c.get(Calendar.HOUR_OF_DAY) * 10000) + 
    (c.get(Calendar.MINUTE) * 100) + 
    (c.get(Calendar.SECOND));
    Log.w("TIME:",String.valueOf(currentTime));
    return(String.valueOf(currentTime));

}


private boolean prepareDirectory() 
{
    try 
    {
        if (makedirs()) 
        {
            return true;
        } else {
            return false;
        }
    } catch (Exception e) 
    {
        e.printStackTrace();
        Toast.makeText(this, "Could not initiate File System.. Is Sdcard mounted properly?", 1000).show();
        return false;
    }
}

private boolean makedirs() 
{
    File tempdir = new File(tempDir);
    if (!tempdir.exists())
        tempdir.mkdirs();

    if (tempdir.isDirectory()) 
    {
        File[] files = tempdir.listFiles();
        for (File file : files) 
        {
            if (!file.delete()) 
            {
                System.out.println("Failed to delete " + file);
            }
        }
    }
    return (tempdir.isDirectory());
}

public class signature extends View 
{
    private static final float STROKE_WIDTH = 5f;
    private static final float HALF_STROKE_WIDTH = STROKE_WIDTH / 2;
    private Paint paint = new Paint();
    private Path path = new Path();

    private float lastTouchX;
    private float lastTouchY;
    private final RectF dirtyRect = new RectF();

    public signature(Context context, AttributeSet attrs) 
    {
        super(context, attrs);
        paint.setAntiAlias(true);
        paint.setColor(Color.BLACK);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeJoin(Paint.Join.ROUND);
        paint.setStrokeWidth(STROKE_WIDTH);
    }

    public void save(View v) 
    {
        Log.v("log_tag", "Width: " + v.getWidth());
        Log.v("log_tag", "Height: " + v.getHeight());
        if(mBitmap == null)
        {
            mBitmap =  Bitmap.createBitmap (mContent.getWidth(), mContent.getHeight(), Bitmap.Config.RGB_565);;
        }
        Canvas canvas = new Canvas(mBitmap);
        try 
        {
            FileOutputStream mFileOutStream = new FileOutputStream(mypath);

            v.draw(canvas); 
            mBitmap.compress(Bitmap.CompressFormat.PNG, 90, mFileOutStream); 
            mFileOutStream.flush();
            mFileOutStream.close();
            String url = Images.Media.insertImage(getContentResolver(), mBitmap, "title", null);
            Log.v("log_tag","url: " + url);
            //In case you want to delete the file
            //boolean deleted = mypath.delete();
            //Log.v("log_tag","deleted: " + mypath.toString() + deleted);
            //If you want to convert the image to string use base64 converter

        }
        catch(Exception e) 
        { 
            Log.v("log_tag", e.toString()); 
        } 
    }

    public void clear() 
    {
        path.reset();
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) 
    {
        canvas.drawPath(path, paint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) 
    {
        float eventX = event.getX();
        float eventY = event.getY();
        mGetSign.setEnabled(true);

        switch (event.getAction()) 
        {
        case MotionEvent.ACTION_DOWN:
            path.moveTo(eventX, eventY);
            lastTouchX = eventX;
            lastTouchY = eventY;
            return true;

        case MotionEvent.ACTION_MOVE:

        case MotionEvent.ACTION_UP:

            resetDirtyRect(eventX, eventY);
            int historySize = event.getHistorySize();
            for (int i = 0; i < historySize; i++) 
            {
                float historicalX = event.getHistoricalX(i);
                float historicalY = event.getHistoricalY(i);
                expandDirtyRect(historicalX, historicalY);
                path.lineTo(historicalX, historicalY);
            }
            path.lineTo(eventX, eventY);
            break;

        default:
            debug("Ignored touch event: " + event.toString());
            return false;
        }

        invalidate((int) (dirtyRect.left - HALF_STROKE_WIDTH),
                (int) (dirtyRect.top - HALF_STROKE_WIDTH),
                (int) (dirtyRect.right + HALF_STROKE_WIDTH),
                (int) (dirtyRect.bottom + HALF_STROKE_WIDTH));

        lastTouchX = eventX;
        lastTouchY = eventY;

        return true;
    }

    private void debug(String string){
    }

    private void expandDirtyRect(float historicalX, float historicalY) 
    {
        if (historicalX < dirtyRect.left) 
        {
            dirtyRect.left = historicalX;
        } 
        else if (historicalX > dirtyRect.right) 
        {
            dirtyRect.right = historicalX;
        }

        if (historicalY < dirtyRect.top) 
        {
            dirtyRect.top = historicalY;
        } 
        else if (historicalY > dirtyRect.bottom) 
        {
            dirtyRect.bottom = historicalY;
        }
    }

    private void resetDirtyRect(float eventX, float eventY) 
    {
        dirtyRect.left = Math.min(lastTouchX, eventX);
        dirtyRect.right = Math.max(lastTouchX, eventX);
        dirtyRect.top = Math.min(lastTouchY, eventY);
        dirtyRect.bottom = Math.max(lastTouchY, eventY);
    }
}

}

main.xml的来源

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="@string/hello"
        android:textSize="25sp" android:paddingBottom="20dp"
        android:textStyle="bold" />
    <Button android:text="Get My Signature" android:id="@+id/signature"
        android:layout_width="wrap_content" android:layout_height="wrap_content" />
</LinearLayout>

signature.xml的来源

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="@+id/linearLayout1"
    android:layout_width="600dp" android:layout_height="400dp"
    android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android">
    <LinearLayout android:layout_height="wrap_content"
        android:id="@+id/linearLayout2" android:layout_width="match_parent">
        <Button android:layout_height="50dp" android:layout_weight=".30"
            android:text="Cancel" android:layout_width="0dp" android:id="@+id/cancel" />
        <Button android:layout_height="50dp" android:layout_weight=".35"
            android:text="Clear" android:layout_width="0dp" android:id="@+id/clear" />
        <Button android:layout_height="50dp" android:layout_weight=".35"
            android:text="Save" android:layout_width="0dp" android:id="@+id/getsign" />
    </LinearLayout>
    <TableLayout android:layout_height="wrap_content"
        android:id="@+id/tableLayout1" android:layout_width="match_parent">
        <TableRow android:id="@+id/tableRow1" android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <TextView android:layout_height="wrap_content" android:id="@+id/textView2"
                android:text="Your Name" android:textAppearance="?android:attr/textAppearanceMedium"
                android:layout_width="wrap_content" android:paddingLeft="10sp"
                android:layout_gravity="right" />
            <EditText android:layout_height="wrap_content" android:id="@+id/yourName"
                android:layout_weight="1" android:layout_width="match_parent"
                android:maxLength="30">
                <requestFocus />
            </EditText>
        </TableRow>
        <TableRow android:id="@+id/tableRow3" android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <TextView android:layout_height="wrap_content" android:id="@+id/textView2"
                android:text="" android:maxLength="30"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:layout_width="wrap_content" />
            <TextView android:layout_height="wrap_content" android:id="@+id/textView2"
                android:text="Please Sign below ..." android:maxLength="30"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:layout_width="wrap_content" />
        </TableRow>
    </TableLayout>
    <LinearLayout android:layout_height="match_parent"
        android:id="@+id/linearLayout" android:layout_width="match_parent" />
</LinearLayout>

在您的清单中添加此权限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

如何从base64字符串

显示已保存的签名

 //convert the string to byte array
 byte[] imageAsBytes = Base64.decode(myStringImage.getBytes());
 //get reference to the image view where you want to display the image
 ImageView image = (ImageView)this.findViewById(R.id.ImageView);
 //set the image by decoding the byte array to bitmap
 image.setImageBitmap(
  BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length)
 );

Android平板电脑应用中的签名捕获实现

1 个答案: