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我正在開發一個應用程序，使用條形碼閱讀器，我從條形碼閱讀器的代碼，我遵循教程。我試圖把它放在導航抽屜裏，這是我的麻煩開始的地方。問題與不兼容的類型 - 片段/活動（Java）
public class MainScreen extends Fragment implements View.OnClickListener
{
//Assign what the user sees to this variable, which XML for example
View MyView;
TextView Result,Result2;
Button Scan;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
MyView = inflater.inflate(R.layout.home_screen,container,false);
Scan=(Button)MyView.findViewById(R.id.btnScan);
Result=(TextView)MyView.findViewById(R.id.txtResult);
Result2=(TextView)MyView.findViewById(R.id.txtResult2);
Scan.setOnClickListener(this);
return MyView;
}
@Override
public void onClick(View v)
{
if (v.getId()==R.id.btnScan)
{
//Error is here
IntentIntegrator ScanIntegrator = new IntentIntegrator(this);
ScanIntegrator.initiateScan();
}
}
正如評論顯示，誤差是IntentIntegrator class的實例化過程中，更具體由「this'-紅線彈出一條消息說，它不能被應用到我的com。示例文件夾中。
運行這樣的代碼給我的錯誤"Error:(60, 68) error: incompatible types: MainScreen cannot be converted to Activity" - 如果我改變MainScreen類的FragmentActivity我得到了同樣的錯誤，只是說，它不能被改變爲一個片段。
這裏是IntentIntegrator類，如果任何人需要看到它。
public class IntentIntegrator {
public static final int REQUEST_CODE = 0x0000c0de; // Only use bottom 16 bits
private static final String TAG = IntentIntegrator.class.getSimpleName();
public static final String DEFAULT_TITLE = "Install Barcode Scanner?";
public static final String DEFAULT_MESSAGE =
"This application requires Barcode Scanner. Would you like to install it?";
public static final String DEFAULT_YES = "Yes";
public static final String DEFAULT_NO = "No";
private static final String BS_PACKAGE = "com.google.zxing.client.android";
private static final String BSPLUS_PACKAGE = "com.srowen.bs.android";
// supported barcode formats
public static final Collection<String> PRODUCT_CODE_TYPES = list("UPC_A", "UPC_E", "EAN_8", "EAN_13", "RSS_14");
public static final Collection<String> ONE_D_CODE_TYPES =
list("UPC_A", "UPC_E", "EAN_8", "EAN_13", "CODE_39", "CODE_93", "CODE_128",
"ITF", "RSS_14", "RSS_EXPANDED");
public static final Collection<String> QR_CODE_TYPES = Collections.singleton("QR_CODE");
public static final Collection<String> DATA_MATRIX_TYPES = Collections.singleton("DATA_MATRIX");
public static final Collection<String> ALL_CODE_TYPES = null;
public static final List<String> TARGET_BARCODE_SCANNER_ONLY = Collections.singletonList(BS_PACKAGE);
public static final List<String> TARGET_ALL_KNOWN = list(
BS_PACKAGE, // Barcode Scanner
BSPLUS_PACKAGE, // Barcode Scanner+
BSPLUS_PACKAGE + ".simple" // Barcode Scanner+ Simple
// What else supports this intent?
);
private final Activity activity;
private String title;
private String message;
private String buttonYes;
private String buttonNo;
private List<String> targetApplications;
private final Map<String,Object> moreExtras;
public IntentIntegrator(Activity activity) {
this.activity = activity;
title = DEFAULT_TITLE;
message = DEFAULT_MESSAGE;
buttonYes = DEFAULT_YES;
buttonNo = DEFAULT_NO;
targetApplications = TARGET_ALL_KNOWN;
moreExtras = new HashMap<String,Object>(3);
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public void setTitleByID(int titleID) {
title = activity.getString(titleID);
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public void setMessageByID(int messageID) {
message = activity.getString(messageID);
}
public String getButtonYes() {
return buttonYes;
}
public void setButtonYes(String buttonYes) {
this.buttonYes = buttonYes;
}
public void setButtonYesByID(int buttonYesID) {
buttonYes = activity.getString(buttonYesID);
}
public String getButtonNo() {
return buttonNo;
}
public void setButtonNo(String buttonNo) {
this.buttonNo = buttonNo;
}
public void setButtonNoByID(int buttonNoID) {
buttonNo = activity.getString(buttonNoID);
}
public Collection<String> getTargetApplications() {
return targetApplications;
}
public final void setTargetApplications(List<String> targetApplications) {
if (targetApplications.isEmpty()) {
throw new IllegalArgumentException("No target applications");
}
this.targetApplications = targetApplications;
}
public void setSingleTargetApplication(String targetApplication) {
this.targetApplications = Collections.singletonList(targetApplication);
}
public Map<String,?> getMoreExtras() {
return moreExtras;
}
public final void addExtra(String key, Object value) {
moreExtras.put(key, value);
}
public final AlertDialog initiateScan() {
return initiateScan(ALL_CODE_TYPES);
}
public final AlertDialog initiateScan(Collection<String> desiredBarcodeFormats) {
Intent intentScan = new Intent(BS_PACKAGE + ".SCAN");
intentScan.addCategory(Intent.CATEGORY_DEFAULT);
// check which types of codes to scan for
if (desiredBarcodeFormats != null) {
// set the desired barcode types
StringBuilder joinedByComma = new StringBuilder();
for (String format : desiredBarcodeFormats) {
if (joinedByComma.length() > 0) {
joinedByComma.append(',');
}
joinedByComma.append(format);
}
intentScan.putExtra("SCAN_FORMATS", joinedByComma.toString());
}
String targetAppPackage = findTargetAppPackage(intentScan);
if (targetAppPackage == null) {
return showDownloadDialog();
}
intentScan.setPackage(targetAppPackage);
intentScan.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intentScan.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
attachMoreExtras(intentScan);
startActivityForResult(intentScan, REQUEST_CODE);
return null;
}
protected void startActivityForResult(Intent intent, int code) {
activity.startActivityForResult(intent, code);
}
private String findTargetAppPackage(Intent intent) {
PackageManager pm = activity.getPackageManager();
List<ResolveInfo> availableApps = pm.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
if (availableApps != null) {
for (ResolveInfo availableApp : availableApps) {
String packageName = availableApp.activityInfo.packageName;
if (targetApplications.contains(packageName)) {
return packageName;
}
}
}
return null;
}
private AlertDialog showDownloadDialog() {
AlertDialog.Builder downloadDialog = new AlertDialog.Builder(activity);
downloadDialog.setTitle(title);
downloadDialog.setMessage(message);
downloadDialog.setPositiveButton(buttonYes, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
String packageName = targetApplications.get(0);
Uri uri = Uri.parse("market://details?id=" + packageName);
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
try {
activity.startActivity(intent);
} catch (ActivityNotFoundException anfe) {
// Hmm, market is not installed
Log.w(TAG, "Google Play is not installed; cannot install " + packageName);
}
}
});
downloadDialog.setNegativeButton(buttonNo, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {}
});
return downloadDialog.show();
}
public static IntentResult parseActivityResult(int requestCode, int resultCode, Intent intent) {
if (requestCode == REQUEST_CODE) {
if (resultCode == Activity.RESULT_OK) {
String contents = intent.getStringExtra("SCAN_RESULT");
String formatName = intent.getStringExtra("SCAN_RESULT_FORMAT");
byte[] rawBytes = intent.getByteArrayExtra("SCAN_RESULT_BYTES");
int intentOrientation = intent.getIntExtra("SCAN_RESULT_ORIENTATION", Integer.MIN_VALUE);
Integer orientation = intentOrientation == Integer.MIN_VALUE ? null : intentOrientation;
String errorCorrectionLevel = intent.getStringExtra("SCAN_RESULT_ERROR_CORRECTION_LEVEL");
return new IntentResult(contents, formatName, rawBytes, orientation, errorCorrectionLevel);
}
return new IntentResult();
}
return null;
}
public final AlertDialog shareText(CharSequence text, CharSequence type) {
Intent intent = new Intent();
intent.addCategory(Intent.CATEGORY_DEFAULT);
intent.setAction(BS_PACKAGE + ".ENCODE");
intent.putExtra("ENCODE_TYPE", type);
intent.putExtra("ENCODE_DATA", text);
String targetAppPackage = findTargetAppPackage(intent);
if (targetAppPackage == null) {
return showDownloadDialog();
}
intent.setPackage(targetAppPackage);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
attachMoreExtras(intent);
activity.startActivity(intent);
return null;
}
private static List<String> list(String... values) {
return Collections.unmodifiableList(Arrays.asList(values));
}
private void attachMoreExtras(Intent intent) {
for (Map.Entry<String,Object> entry : moreExtras.entrySet()) {
String key = entry.getKey();
Object value = entry.getValue();
// Kind of hacky
if (value instanceof Integer) {
intent.putExtra(key, (Integer) value);
} else if (value instanceof Long) {
intent.putExtra(key, (Long) value);
} else if (value instanceof Boolean) {
intent.putExtra(key, (Boolean) value);
} else if (value instanceof Double) {
intent.putExtra(key, (Double) value);
} else if (value instanceof Float) {
intent.putExtra(key, (Float) value);
} else if (value instanceof Bundle) {
intent.putExtra(key, (Bundle) value);
} else {
intent.putExtra(key, value.toString());
}
}
}
}
感謝
我敢打賭，你混合使用非詢問服務片段支持 – Selvin