android中的Wifi打印不起作用 [英] Wifi Printing in android is not working
本文介绍了android中的Wifi打印不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我制作了一个 android 应用程序，用于使用连接到 wifi 的打印机打印 pdf 文件.我已经按照下面的代码尝试过，它只是搜索设备，但什么也没发生.请查看我的代码并告诉我应该做哪些更改来解决我的问题.任何输入将不胜感激！
I have made an android app for printing pdf file using printer which is connected to wifi. I have tried as per below code, Its only searching for the devices but nothing is happened. Please see my code and tell me what changes should I do to solve my problem. Any inputs will be appreciated!
代码
public class MainActivity extends Activity {
public int pageHeight;
public int pageWidth;
public PdfDocument myPdfDocument;
public int totalpages = 4;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public class MyPrintDocumentAdapter extends PrintDocumentAdapter {
Context context;
public MyPrintDocumentAdapter(Context context) {
this.context = context;
}
@SuppressLint("InlinedApi")
@Override
public void onLayout(PrintAttributes oldAttributes,
PrintAttributes newAttributes,
CancellationSignal cancellationSignal,
LayoutResultCallback callback, Bundle metadata) {
myPdfDocument = new PrintedPdfDocument(context, newAttributes);
pageHeight = newAttributes.getMediaSize().getHeightMils() / 1000 * 72;
pageWidth = newAttributes.getMediaSize().getWidthMils() / 1000 * 72;
if (cancellationSignal.isCanceled()) {
callback.onLayoutCancelled();
return;
}
if (totalpages > 0) {
PrintDocumentInfo.Builder builder = new PrintDocumentInfo.Builder(
"print_output.pdf").setContentType(
PrintDocumentInfo.CONTENT_TYPE_DOCUMENT).setPageCount(
totalpages);
PrintDocumentInfo info = builder.build();
callback.onLayoutFinished(info, true);
} else {
callback.onLayoutFailed("Page count is zero.");
}
}
@Override
public void onWrite(final PageRange[] pageRanges,
final ParcelFileDescriptor destination,
final CancellationSignal cancellationSignal,
final WriteResultCallback callback) {
for (int i = 0; i < totalpages; i++) {
if (pageInRange(pageRanges, i)) {
PageInfo newPage = new PageInfo.Builder(pageWidth,
pageHeight, i).create();
PdfDocument.Page page = myPdfDocument.startPage(newPage);
if (cancellationSignal.isCanceled()) {
callback.onWriteCancelled();
myPdfDocument.close();
myPdfDocument = null;
return;
}
drawPage(page, i);
myPdfDocument.finishPage(page);
}
}
try {
myPdfDocument.writeTo(new FileOutputStream(destination
.getFileDescriptor()));
} catch (IOException e) {
callback.onWriteFailed(e.toString());
return;
} finally {
myPdfDocument.close();
myPdfDocument = null;
}
callback.onWriteFinished(pageRanges);
}
private boolean pageInRange(PageRange[] pageRanges, int page) {
for (int i = 0; i < pageRanges.length; i++) {
if ((page >= pageRanges[i].getStart())
&& (page <= pageRanges[i].getEnd()))
return true;
}
return false;
}
private void drawPage(PdfDocument.Page page, int pagenumber) {
Canvas canvas = page.getCanvas();
pagenumber++; // Make sure page numbers start at 1
int titleBaseLine = 72;
int leftMargin = 54;
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setTextSize(40);
canvas.drawText("Test Print Document Page " + pagenumber,
leftMargin, titleBaseLine, paint);
paint.setTextSize(14);
canvas.drawText(
"This is some test content to verify that custom document printing works",
leftMargin, titleBaseLine + 35, paint);
if (pagenumber % 2 == 0)
paint.setColor(Color.RED);
else
paint.setColor(Color.GREEN);
PageInfo pageInfo = page.getInfo();
canvas.drawCircle(pageInfo.getPageWidth() / 2,
pageInfo.getPageHeight() / 2, 150, paint);
}
}
@SuppressLint("InlinedApi")
public void printDocument(View view) {
PrintManager printManager = (PrintManager) this
.getSystemService(Context.PRINT_SERVICE);
String jobName = this.getString(R.string.app_name) + " Document";
printManager.print(jobName, new MyPrintDocumentAdapter(this), null);
}
}
推荐答案
可以参考这个Android-wifi-print - GitHub.我已经创建了一个用于打印的演示应用程序.这是我的流量.！这会对你有所帮助.
you can refer to this Android-wifi-print - GitHub. I have created a demo application for printing.. This is my flow.! which will help you a bit.
在以下链接的帮助下，我创建了这个.
With the help of following links I have created this.
这是那个原型的流程.
- 检查连接.
- 如果通过 WiFi 连接...正在存储该 WiFi 配置.
- 现在检查我是否已经有打印机信息(WiFi 打印机的 WiFi 配置)是否可用.如果可用，我将扫描并获取 WiFi ScanResults 列表并连接到其他列表.它会显示 WiFi 列表并点击它，用户将连接到打印机并存储该 WiFi 配置以备将来打印作业.
- 打印作业完成后，我将连接到以前的 WiFi 或移动数据连接.
- 现在回到第二步.
- 如果用户使用移动数据连接，我只需启用 WiFi 并执行第 3 步.
- 打印作业完成后，我只是禁用了 WiFi.这样，我们将连接回移动数据连接.(这是安卓默认设置).
如果您想打印文件，只需在 PrintUtility.class 中调用 print(file)以下课程将负责所有印刷工作..
If you want to print a file just call print(file) in PrintUtility.class Following class will take care of all printing jobs..
public class PrintUtility implements Observer {
private static final int TIME_OUT = 10000;
private static final int CONNECTION_TIME_OUT = 5000;
private Activity mActivity;
private Fragment mFragment = null;
private WifiConfiguration mPrinterConfiguration;
private WifiConfiguration mOldWifiConfiguration;
private WifiManager mWifiManager;
private WifiScanner mWifiScanner;
private List<ScanResult> mScanResults = new ArrayList<ScanResult>();
private PrintManager mPrintManager;
private List<PrintJob> mPrintJobs;
private PrintJob mCurrentPrintJob;
private File pdfFile;
private String externalStorageDirectory;
private Handler mPrintStartHandler = new Handler();
private Handler mPrintCompleteHandler = new Handler();
private Handler mWifiConnectHandler = new Handler();
private String connectionInfo;
private boolean isMobileDataConnection = false;
private PrintCompleteService mPrintCompleteService;
// Observer pattern
private Observable mObservable;
public PrintUtility(Activity mActivity, WifiManager mWifiManager, WifiScanner mWifiScanner) {
this.mActivity = mActivity;
this.mWifiManager = mWifiManager;
this.mWifiScanner = mWifiScanner;
mPrintCompleteService = (PrintCompleteService) mActivity;
mObservable = ObservableSingleton.getInstance();
mObservable.attach(this);
}
public PrintUtility(Activity mActivity, Fragment mFragment, WifiManager mWifiManager, WifiScanner mWifiScanner) {
this.mActivity = mActivity;
this.mFragment = mFragment;
this.mWifiManager = mWifiManager;
this.mWifiScanner = mWifiScanner;
mPrintCompleteService = (PrintCompleteService) mFragment;
mObservable = ObservableSingleton.getInstance();
mObservable.attach(this);
}
public void downloadAndPrint(String fileUrl, final String fileName) {
new FileDownloader(mActivity, fileUrl, fileName) {
@Override
protected void onPostExecute(Boolean result) {
if (!result) {
mObservable.notifyObserver(true);
} else {
// print flow will come here.
try {
externalStorageDirectory = Environment.getExternalStorageDirectory().toString();
File folder = new File(externalStorageDirectory, Constants.CONTROLLER_PDF_FOLDER);
pdfFile = new File(folder, fileName);
} catch (Exception e) {
mObservable.notifyObserver(true);
e.printStackTrace();
}
print(pdfFile);
}
}
}.execute("");
}
public void print(final File pdfFile) {
this.pdfFile = pdfFile;
// check connectivity info -> mobile or wifi.
connectionInfo = Util.connectionInfo(mActivity);
if (connectionInfo.equalsIgnoreCase(Constants.CONTROLLER_MOBILE)) {
// follow mobile flow.
isMobileDataConnection = true;
if (mWifiManager.isWifiEnabled() == false) {
mWifiManager.setWifiEnabled(true);
}
mWifiManager.startScan();
setScanResults(mWifiScanner.getScanResults());
printerConfiguration();
} else if (connectionInfo.equalsIgnoreCase(Constants.CONTROLLER_WIFI)) {
// follow wifi flow..
// this will get current wifiInfo and store it in shared preference.
Util.storeCurrentWiFiConfiguration(mActivity);
printerConfiguration();
} else {
mObservable.notifyObserver(true);
}
}
private void printerConfiguration() {
// check printer detail is available or not.
mPrinterConfiguration = Util.getWifiConfiguration(mActivity, Constants.CONTROLLER_PRINTER);
if (mPrinterConfiguration == null) {
// printer configuration is not available.
// display list of wifi available in an activity
showWifiListActivity(Constants.REQUEST_CODE_PRINTER);
} else {
// get list of wifi available. if printer configuration available then connect it.
// else.. show list of available wifi nearby.
boolean isPrinterAvailable = false;
// scans nearby wifi..
mWifiManager.startScan();
setScanResults(mWifiScanner.getScanResults());
// checks this wifi in scan result list..
for (int i = 0; i < mScanResults.size(); i++) {
if (mPrinterConfiguration.SSID.equals("\"" + mScanResults.get(i).SSID + "\"")) {
isPrinterAvailable = true;
break;
}
}
if (isPrinterAvailable) {
// connect to printer wifi and show print settings dialog and continue with print flow.
connectToWifi(mPrinterConfiguration);
// prints document.
doPrint();
} else {
showWifiListActivity(Constants.REQUEST_CODE_PRINTER);
}
}
}
private void showWifiListActivity(int requestCode) {
Intent iWifi = new Intent(mActivity, WifiListActivity.class);
mActivity.startActivityForResult(iWifi, requestCode);
}
private void connectToWifi(WifiConfiguration mWifiConfiguration) {
mWifiManager.enableNetwork(mWifiConfiguration.networkId, true);
}
public void doPrint() {
try {
// it is taking some time to connect to printer.. so i used handler.. and waiting for its status.
mPrintStartHandler.postDelayed(new Runnable() {
@Override
public void run() {
mPrintStartHandler.postDelayed(this, TIME_OUT);
if (mPrinterConfiguration.status == WifiConfiguration.Status.CURRENT) {
if (mWifiManager.getConnectionInfo().getSupplicantState() == SupplicantState.COMPLETED) {
if (Util.computePDFPageCount(pdfFile) > 0) {
printDocument(pdfFile);
} else {
AlertDialog.Builder alert = new AlertDialog.Builder(mActivity);
alert.setMessage("Can't print, Page count is zero.");
alert.setNeutralButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int i) {
dialog.dismiss();
switchConnection();
}
});
alert.show();
}
}
mPrintStartHandler.removeCallbacksAndMessages(null);
} else {
Toast.makeText(mActivity, "Failed to connect to printer!.", Toast.LENGTH_LONG).show();
switchConnection();
mPrintStartHandler.removeCallbacksAndMessages(null);
}
}
}, TIME_OUT);
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(mActivity, "Failed to connect to printer!.", Toast.LENGTH_LONG).show();
switchConnection();
}
}
@TargetApi(Build.VERSION_CODES.KITKAT)
public void printDocument(File pdfFile) {
mPrintManager = (PrintManager) mActivity.getSystemService(Context.PRINT_SERVICE);
String jobName = mActivity.getResources().getString(R.string.app_name) + " Document";
mCurrentPrintJob = mPrintManager.print(jobName, new PrintServicesAdapter(mActivity, mFragment, pdfFile), null);
}
@TargetApi(Build.VERSION_CODES.KITKAT)
public void completePrintJob() {
mPrintJobs = mPrintManager.getPrintJobs();
mPrintCompleteHandler.postDelayed(new Runnable() {
@Override
public void run() {
mPrintCompleteHandler.postDelayed(this, CONNECTION_TIME_OUT);
if (mCurrentPrintJob.getInfo().getState() == PrintJobInfo.STATE_COMPLETED) {
// remove that PrintJob from PrintManager.
for (int i = 0; i < mPrintJobs.size(); i++) {
if (mPrintJobs.get(i).getId() == mCurrentPrintJob.getId()) {
mPrintJobs.remove(i);
}
}
// switching back to previous connection..
switchConnection();
// stops handler..
mPrintCompleteHandler.removeCallbacksAndMessages(null);
} else if (mCurrentPrintJob.getInfo().getState() == PrintJobInfo.STATE_FAILED) {
switchConnection();
Toast.makeText(mActivity, "Print Failed!", Toast.LENGTH_LONG).show();
mPrintCompleteHandler.removeCallbacksAndMessages(null);
} else if (mCurrentPrintJob.getInfo().getState() == PrintJobInfo.STATE_CANCELED) {
switchConnection();
Toast.makeText(mActivity, "Print Cancelled!", Toast.LENGTH_LONG).show();
mPrintCompleteHandler.removeCallbacksAndMessages(null);
}
}
}, CONNECTION_TIME_OUT);
}
public void switchConnection() {
try {
if (!isMobileDataConnection) {
mOldWifiConfiguration = Util.getWifiConfiguration(mActivity, Constants.CONTROLLER_WIFI);
// get list of wifi available. if wifi configuration available then connect it.
// else.. show list of available wifi nearby.
boolean isWifiAvailable = false;
// scans nearby wifi.
mWifiManager.startScan();
setScanResults(mWifiScanner.getScanResults());
// checks this wifi in scan result list.
for (int i = 0; i < mScanResults.size(); i++) {
if (mOldWifiConfiguration.SSID.equals("\"" + mScanResults.get(i).SSID + "\"")) {
isWifiAvailable = true;
break;
}
}
if (isWifiAvailable) {
// connect to printer wifi and show print settings dialog and continue with print flow.
connectToWifi(mOldWifiConfiguration);
mWifiConnectHandler.postDelayed(new Runnable() {
@Override
public void run() {
mWifiConnectHandler.postDelayed(this, TIME_OUT);
if (mOldWifiConfiguration.status == WifiConfiguration.Status.CURRENT) {
if (mWifiManager.getConnectionInfo().getSupplicantState() == SupplicantState.COMPLETED) {
try {
mObservable.notifyObserver(true);
} catch (Exception e) {
e.printStackTrace();
}
mWifiConnectHandler.removeCallbacksAndMessages(null);
}
}
}
}, TIME_OUT);
} else {
showWifiListActivity(Constants.REQUEST_CODE_WIFI);
}
} else {
mWifiManager.setWifiEnabled(false);
mObservable.notifyObserver(true);
}
} catch (Exception e) {
mObservable.notifyObserver(true);
e.printStackTrace();
}
}
public void getPrinterConfigAndPrint() {
mPrinterConfiguration = Util.getWifiConfiguration(mActivity, Constants.CONTROLLER_PRINTER);
doPrint();
}
public void setScanResults(List<ScanResult> scanResults) {
this.mScanResults = scanResults;
}
public void onPrintCancelled() {
switchConnection();
}
@Override
public void update() {
mObservable.detach(this);
}
@Override
public void updateObserver(boolean bool) {
}
@Override
public void updateObserverProgress(int percentage) {
}
}
这篇关于android中的Wifi打印不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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