我使用以下教程构建了一个签名捕获Android应用程序：
http://www.mysamplecode.com/2011/11/android-capture-signature-using-canvas.html
但是我得到了几个错误说明：
external_dir cannot be resolved or is not a field CaptureSignature.java /example/src/com/example/example line 59 Java Problem
linearLayout cannot be resolved or is not a field CaptureSignature.java /example/src/com/example/example line 67 Java Problem
clear cannot be resolved or is not a field CaptureSignature.java /example/src/com/example/example line 71 Java Problem
getsign cannot be resolved or is not a field CaptureSignature.java /example/src/com/example/example line 72 Java Problem
cancel cannot be resolved or is not a field CaptureSignature.java /example/src/com/example/example line 74 Java Problem
yourName cannot be resolved or is not a field CaptureSignature.java /example/src/com/example/example line 77 Java Problem
R cannot be resolved to a variable CaptureSignatureActivity.java /example/src/com/example/example line 21 Java Problem
external_dir cannot be resolved or is not a field CaptureSignature.java /example/src/com/example/example line 57 Java Problem
R cannot be resolved to a variable CaptureSignatureActivity.java /example/src/com/example/example line 19 Java Problem
signature cannot be resolved or is not a field CaptureSignature.java /example/src/com/example/example line 55 Java Problem
......我不确定为什么。 （我按照一步一步的例子）
有什么建议吗？
消息来源：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);
}
}
}
消息来源：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;
}
}
}
清单：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.as400samplecode" android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="10" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application android:icon="@drawable/icon" android:label="@string/app_name"
android:theme="@android:style/Theme.Light">
<activity android:name=".CaptureSignatureActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".CaptureSignature" android:label="Signature Confirmation"
android:theme="@android:style/Theme.Dialog" />
</application>
</manifest>
的字符串：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, CaptureSignatureActivity!</string>
<string name="app_name">CaptureSignature</string>
<string name="external_dir">GetSignature</string>
</resources>