Qt for Android Qt for Android enables you to run Qt 5 applications Android devices. All Qt modules (essential and add-on) are supported except Qt WebE ...
Qt for Android
Qt for Android enables you to run Qt 5 applications Android devices. All Qt modules (essential and add-on) are supported except Qt WebEngine, Qt Serial Port, and the platform-specific ones (Qt Mac Extras, Qt Windows Extras, and Qt X11 Extras).
在Windows或者Linux平臺上可以用QtWebEngine模塊實現網頁預覽和列印成PDF文檔,用起來很方便,生成的文檔質量也比較好,但在Android平臺上QtWebEngine模塊不能用,想要顯示網頁可以用QtWebView模塊,不支持列印成PDF。嘗試用QTextDocument和QPrinter將html轉為PDF,發現QTextDocument不支持CSS樣式,生成的PDF文檔排版是錯的。
查看QtWebView在Android平臺上的實現,可以發現其用的就是Android的WebView控制項實現的網頁顯示。嘗試在Android平臺上實現html生成PDF,找到了這篇文章https://www.jianshu.com/p/d82bd61b11a4,驗證後可行。需要依賴第三方庫DexMaker,可以用谷歌實現的 implementation 'com.google.dexmaker:dexmaker:1.2',庫文件名為dexmaker-1.2.jar。
修改QT源碼,在Android平臺上實現html轉PDF的功能
- 修改$QtSrc/qtwebview/src/jar/src/org/qtproject/qt5/android/view/QtAndroidWebViewController.java文件
/**************************************************************************** ** ** Copyright (C) 2015 The Qt Company Ltd. ** Contact: http://www.qt.io/licensing/ ** ** This file is part of the QtWebView module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL3$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see http://www.qt.io/terms-conditions. For further ** information use the contact form at http://www.qt.io/contact-us. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 3 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPLv3 included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: https://www.gnu.org/licenses/lgpl.html. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 2.0 or later as published by the Free ** Software Foundation and appearing in the file LICENSE.GPL included in ** the packaging of this file. Please review the following information to ** ensure the GNU General Public License version 2.0 requirements will be ** met: http://www.gnu.org/licenses/gpl-2.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ package org.qtproject.qt5.android.view; import android.content.pm.PackageManager; import android.view.View; import android.webkit.GeolocationPermissions; import android.webkit.URLUtil; import android.webkit.ValueCallback; import android.annotation.SuppressLint; import android.content.Context; import android.os.Bundle; import android.os.CancellationSignal; import android.os.ParcelFileDescriptor; import android.print.PageRange; import android.print.PrintAttributes; import android.print.PrintDocumentAdapter; import android.webkit.WebView; import android.webkit.WebViewClient; import android.webkit.WebChromeClient; import java.lang.Runnable; import android.app.Activity; import android.content.Intent; import android.net.Uri; import java.lang.String; import android.webkit.WebSettings; import android.webkit.WebSettings.PluginState; import android.graphics.Bitmap; import java.util.concurrent.Semaphore; import java.io.File; import java.io.IOException; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import android.os.Build; import java.util.concurrent.TimeUnit; import com.google.dexmaker.stock.ProxyBuilder; public class QtAndroidWebViewController { private final Activity m_activity; private final long m_id; private boolean busy; private boolean m_hasLocationPermission; private WebView m_webView = null; private static final String TAG = "QtAndroidWebViewController"; private final int INIT_STATE = 0; private final int STARTED_STATE = 1; private final int LOADING_STATE = 2; private final int FINISHED_STATE = 3; private volatile int m_loadingState = INIT_STATE; private volatile int m_progress = 0; private volatile int m_frameCount = 0; // API 11 methods private Method m_webViewOnResume = null; private Method m_webViewOnPause = null; private Method m_webSettingsSetDisplayZoomControls = null; // API 19 methods private Method m_webViewEvaluateJavascript = null; // Native callbacks private native void c_onPageFinished(long id, String url); private native void c_onPageStarted(long id, String url, Bitmap icon); private native void c_onProgressChanged(long id, int newProgress); private native void c_onReceivedIcon(long id, Bitmap icon); private native void c_onReceivedTitle(long id, String title); private native void c_onRunJavaScriptResult(long id, long callbackId, String result); private native void c_onReceivedError(long id, int errorCode, String description, String url); private native void c_onpdfPrintingFinished(long id, boolean succeed); // We need to block the UI thread in some cases, if it takes to long we should timeout before // ANR kicks in... Usually the hard limit is set to 10s and if exceed that then we're in trouble. // In general we should not let input events be delayed for more then 500ms (If we're spending more // then 200ms somethings off...). private final long BLOCKING_TIMEOUT = 250; private void resetLoadingState(final int state) { m_progress = 0; m_frameCount = 0; m_loadingState = state; } private class Html2Pdf { private File file; private File dexCacheFile; private PrintDocumentAdapter printAdapter; private PageRange[] ranges; private ParcelFileDescriptor descriptor; private void printToPdf(WebView webView, String fileName) { if (webView != null) { file = new File(fileName); dexCacheFile = webView.getContext().getDir("dex", 0); if (!dexCacheFile.exists()) { dexCacheFile.mkdir(); } try { if (file.exists()) { file.delete(); } file.createNewFile(); descriptor = ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_WRITE); PrintAttributes attributes = new PrintAttributes.Builder() .setMediaSize(PrintAttributes.MediaSize.ISO_A4) .setResolution(new PrintAttributes.Resolution("id", Context.PRINT_SERVICE, 300, 300)) .setColorMode(PrintAttributes.COLOR_MODE_COLOR) .setMinMargins(PrintAttributes.Margins.NO_MARGINS) .build(); ranges = new PageRange[]{PageRange.ALL_PAGES}; printAdapter = webView.createPrintDocumentAdapter(); printAdapter.onStart(); printAdapter.onLayout(attributes, attributes, new CancellationSignal(), getLayoutResultCallback(new InvocationHandler() { @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { if (method.getName().equals("onLayoutFinished")) { onLayoutSuccess(); } else { descriptor.close(); c_onpdfPrintingFinished(m_id, false); busy = false; } return null; } }, dexCacheFile.getAbsoluteFile()), new Bundle()); } catch (IOException e) { if (descriptor != null) { try { descriptor.close(); } catch (IOException ex) { ex.printStackTrace(); } } c_onpdfPrintingFinished(m_id, false); e.printStackTrace(); busy = false; } } } private void onLayoutSuccess() throws IOException { PrintDocumentAdapter.WriteResultCallback callback = getWriteResultCallback(new InvocationHandler() { @Override public Object invoke(Object o, Method method, Object[] objects) throws Throwable { if (method.getName().equals("onWriteFinished")) { c_onpdfPrintingFinished(m_id, true); } else { c_onpdfPrintingFinished(m_id, false); } busy = false; if (descriptor != null) { try { descriptor.close(); } catch (IOException ex) { ex.printStackTrace(); } } return null; } }, dexCacheFile.getAbsoluteFile()); printAdapter.onWrite(ranges, descriptor, new CancellationSignal(), callback); } @SuppressLint("NewApi") private PrintDocumentAdapter.LayoutResultCallback getLayoutResultCallback(InvocationHandler invocationHandler, File dexCacheDir) throws IOException { return ProxyBuilder.forClass(PrintDocumentAdapter.LayoutResultCallback.class) .dexCache(dexCacheDir) .handler(invocationHandler) .build(); } @SuppressLint("NewApi") private PrintDocumentAdapter.WriteResultCallback getWriteResultCallback(InvocationHandler invocationHandler, File dexCacheDir) throws IOException { return ProxyBuilder.forClass(PrintDocumentAdapter.WriteResultCallback.class) .dexCache(dexCacheDir) .handler(invocationHandler) .build(); } } private class QtAndroidWebViewClient extends WebViewClient { QtAndroidWebViewClient() { super(); } @Override public boolean shouldOverrideUrlLoading(WebView view, String url) { // handle http: and http:, etc., as usual if (URLUtil.isValidUrl(url)) return false; // try to handle geo:, tel:, mailto: and other schemes try { Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url)); view.getContext().startActivity(intent); return true; } catch (Exception e) { e.printStackTrace(); } return false; } @Override public void onLoadResource(WebView view, String url) { super.onLoadResource(view, url); } @Override public void onPageFinished(WebView view, String url) { super.onPageFinished(view, url); m_loadingState = FINISHED_STATE; if (m_progress != 100) // onProgressChanged() will notify Qt if we didn't finish here. return; m_frameCount = 0; c_onPageFinished(m_id, url); } @Override public void onPageStarted(WebView view, String url, Bitmap favicon) { super.onPageStarted(view, url, favicon); if (++m_frameCount == 1) { // Only call onPageStarted for the first frame. m_loadingState = LOADING_STATE; c_onPageStarted(m_id, url, favicon); } } @Override public void onReceivedError(WebView view, int errorCode, String description, String url) { super.onReceivedError(view, errorCode, description, url); resetLoadingState(INIT_STATE); c_onReceivedError(m_id, errorCode, description, url); } } private class QtAndroidWebChromeClient extends WebChromeClient { QtAndroidWebChromeClient() { super(); } @Override public void onProgressChanged(WebView view, int newProgress) { super.onProgressChanged(view, newProgress); m_progress = newProgress; c_onProgressChanged(m_id, newProgress); if (m_loadingState == FINISHED_STATE && m_progress == 100) { // Did we finish? m_frameCount = 0; c_onPageFinished(m_id, view.getUrl()); } } @Override public void onReceivedIcon(WebView view, Bitmap icon) { super.onReceivedIcon(view, icon); c_onReceivedIcon(m_id, icon); } @Override public void onReceivedTitle(WebView view, String title) { super.onReceivedTitle(view, title); c_onReceivedTitle(m_id, title); } @Override public void onGeolocationPermissionsShowPrompt(String origin, GeolocationPermissions.Callback callback) { callback.invoke(origin, m_hasLocationPermission, false); } } public QtAndroidWebViewController(final Activity activity, final long id) { m_activity = activity; m_id = id; final Semaphore sem = new Semaphore(0); m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView = new WebView(m_activity); m_hasLocationPermission = hasLocationPermission(m_webView); WebSettings webSettings = m_webView.getSettings(); if (Build.VERSION.SDK_INT > 10) { try { m_webViewOnResume = m_webView.getClass().getMethod("onResume"); m_webViewOnPause = m_webView.getClass().getMethod("onPause"); m_webSettingsSetDisplayZoomControls = webSettings.getClass().getMethod("setDisplayZoomControls", boolean.class); if (Build.VERSION.SDK_INT > 18) { m_webViewEvaluateJavascript = m_webView.getClass().getMethod("evaluateJavascript", String.class, ValueCallback.class); } } catch (Exception e) { /* Do nothing */ e.printStackTrace(); } } //allowing access to location without actual ACCESS_FINE_LOCATION may throw security exception webSettings.setGeolocationEnabled(m_hasLocationPermission); webSettings.setJavaScriptEnabled(true); if (m_webSettingsSetDisplayZoomControls != null) { try { m_webSettingsSetDisplayZoomControls.invoke(webSettings, false); } catch (Exception e) { e.printStackTrace(); } } webSettings.setBuiltInZoomControls(true); webSettings.setPluginState(PluginState.ON); m_webView.setWebViewClient((WebViewClient)new QtAndroidWebViewClient()); m_webView.setWebChromeClient((WebChromeClient)new QtAndroidWebChromeClient()); sem.release(); } }); try { sem.acquire(); } catch (Exception e) { e.printStackTrace(); } } public void loadUrl(final String url) { if (url == null) { return; } resetLoadingState(STARTED_STATE); c_onPageStarted(m_id, url, null); m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView.loadUrl(url); } }); } public void loadData(final String data, final String mimeType, final String encoding) { if (data == null) return; resetLoadingState(STARTED_STATE); c_onPageStarted(m_id, null, null); m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView.loadData(data, mimeType, encoding); } }); } public void loadDataWithBaseURL(final String baseUrl, final String data, final String mimeType, final String encoding, final String historyUrl) { if (data == null) return; resetLoadingState(STARTED_STATE); c_onPageStarted(m_id, null, null); m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView.loadDataWithBaseURL(baseUrl, data, mimeType, encoding, historyUrl); } }); } public void goBack() { m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView.goBack(); } }); } public boolean canGoBack() { final boolean[] back = {false}; final Semaphore sem = new Semaphore(0); m_activity.runOnUiThread(new Runnable() { @Override public void run() { back[0] = m_webView.canGoBack(); sem.release(); } }); try { sem.tryAcquire(BLOCKING_TIMEOUT, TimeUnit.MILLISECONDS); } catch (Exception e) { e.printStackTrace(); } return back[0]; } public void goForward() { m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView.goForward(); } }); } public boolean canGoForward() { final boolean[] forward = {false}; final Semaphore sem = new Semaphore(0); m_activity.runOnUiThread(new Runnable() { @Override public void run() { forward[0] = m_webView.canGoForward(); sem.release(); } }); try { sem.tryAcquire(BLOCKING_TIMEOUT, TimeUnit.MILLISECONDS); } catch (Exception e) { e.printStackTrace(); } return forward[0]; } public void stopLoading() { m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView.stopLoading(); } }); } public void reload() { m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView.reload(); } }); } public String getTitle() { final String[] title = {""}; final Semaphore sem = new Semaphore(0); m_activity.runOnUiThread(new Runnable() { @Override public void run() { title[0] = m_webView.getTitle(); sem.release(); } }); try { sem.tryAcquire(BLOCKING_TIMEOUT, TimeUnit.MILLISECONDS); } catch (Exception e) { e.printStackTrace(); } return title[0]; } public int getProgress() { return m_progress; } public boolean isLoading() { return m_loadingState == LOADING_STATE || m_loadingState == STARTED_STATE || (m_progress > 0 && m_progress < 100); } public void runJavaScript(final String script, final long callbackId) { if (script == null) return; if (Build.VERSION.SDK_INT < 19 || m_webViewEvaluateJavascript == null) return; m_activity.runOnUiThread(new Runnable() { @Override public void run() { try { m_webViewEvaluateJavascript.invoke(m_webView, script, callbackId == -1 ? null : new ValueCallback<String>() { @Override public void onReceiveValue(String result) { c_onRunJavaScriptResult(m_id, callbackId, result); } }); } catch (Exception e) { e.printStackTrace(); } } }); } public String getUrl() { final String[] url = {""}; final Semaphore sem = new Semaphore(0); m_activity.runOnUiThread(new Runnable() { @Override public void run() { url[0] = m_webView.getUrl(); sem.release(); } }); try { sem.tryAcquire(BLOCKING_TIMEOUT, TimeUnit.MILLISECONDS); } catch (Exception e) { e.printStackTrace(); } return url[0]; } public WebView getWebView() { return m_webView; } public void onPause() { if (m_webViewOnPause == null) return; m_activity.runOnUiThread(new Runnable() { @Override public void run() { try { m_webViewOnPause.invoke(m_webView); } catch (Exception e) { e.printStackTrace(); } } }); } public void onResume() { if (m_webViewOnResume == null) return; m_activity.runOnUiThread(new Runnable() { @Override public void run() { try { m_webViewOnResume.invoke(m_webView); } catch (Exception e) { e.printStackTrace(); } } }); } private static boolean hasLocationPermission(View view) { final String name = view.getContext().getPackageName(); final PackageManager pm = view.getContext().getPackageManager(); return pm.checkPermission("android.permission.ACCESS_FINE_LOCATION", name) == PackageManager.PERMISSION_GRANTED; } public void destroy() { m_activity.runOnUiThread(new Runnable() { @Override public void run() { m_webView.destroy(); } }); } public void printToPdf(final String fileName){ if(!busy){ busy = true; m_activity.runOnUiThread(new Runnable() { @Override public void run() { Html2Pdf html2Pdf = new Html2Pdf(); html2Pdf.printToPdf(m_webView, fileName); } }); }else{ c_onpdfPrintingFinished(m_id,false); } } }
- 主要修改:
- 增加了 void printToPdf(final String fileName)列印介面
- 增加了 native void c_onpdfPrintingFinished(long id, boolean succeed)作為列印完成的回調
- 增加了內部類Html2Pdf實現列印成PDF
- 修改$QtSrc/qtwebview/src/plugins/android/qandroidwebview_p.h
- 增加槽函數 void printToPdf(const QString &fileName) Q_DECL_OVERRIDE;
- 修改$QtSrc/qtwebview/src/plugins/android/qandroidwebview.cpp
- 實現槽函數
void QAndroidWebViewPrivate::printToPdf(const QString &fileName) { const QJNIObjectPrivate &fileNameString = QJNIObjectPrivate::fromString(fileName); m_viewController.callMethod<void>("printToPdf","(Ljava/lang/String;)V",fileNameString.object()); }
- 實現java代碼中列印完成的回調
static void c_onpdfPrintingFinished(JNIEnv *env, jobject thiz, jlong id, jboolean succeed) { Q_UNUSED(env) Q_UNUSED(thiz) const WebViews &wv = (*g_webViews); QAndroidWebViewPrivate *wc = wv[id]; if (!wc) return; Q_EMIT wc->pdfPrintingFinished(succeed); }
- 修改JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void* /*reserved*/),註冊c_onpdfPrintingFinished回調函數。
JNINativeMethod methods[]數組裡增加一項 {"c_onpdfPrintingFinished","(JZ)V",reinterpret_cast<void *>(c_onpdfPrintingFinished)}
- 修改$QtSrc/qtwebview/src/webview/qabstractwebview_p.h(以下增加的所有的C++代碼、函數、信號等都用#if ANDROID巨集條件編譯)
- 增加信號void pdfPrintingFinished(bool succeed);
- 修改$QtSrc/qtwebview/src/webview/qquickwebview_p.h
- 增加公開槽函數 void printToPdf(const QString &fileName) Q_DECL_OVERRIDE;
- 增加信號 void pdfPrintingFinished(bool succeed);
- 增加私有槽函數 void onPdfPrintingFinished(bool succeed);
- 修改$QtSrc/qtwebview/src/webview/qquickwebview.cpp
- 構造函數里關聯槽函數和信號
#if ANDROID connect(m_webView, &QWebView::pdfPrintingFinished, this, &QQuickWebView::onPdfPrintingFinished); #endif
- 實現槽函數printToPdf
#if ANDROID void QQuickWebView::printToPdf(const QString &fileName) { m_webView->printToPdf(fileName); } #endif
- 實現槽函數onPdfPrintingFinished
#if ANDROID void QQuickWebView::onPdfPrintingFinished(bool succeed) { Q_EMIT pdfPrintingFinished(succeed); } #endif
- 修改$QtSrc/qtwebview/src/webview/qwebviewinterface_p.h
- 增加純虛函數 virtual void printToPdf(const QString &fileName) = 0;
- 修改$QtSrc/qtwebview/src/webview/qwebviewfactory.cpp
- QNullWebView類增加
void printToPdf(const QString &fileName) override {Q_UNUSED(fileName); }
- 修改$QtSrc/qtwebview/src/webview/qwebview_p.h
- 增加公開槽函數 void printToPdf(const QString &fileName) Q_DECL_OVERRIDE;
- 增加信號 void pdfPrintingFinished(bool succeed);
- 增加私有槽函數 void onPdfPrintingFinished(bool succeed);
- 修改$QtSrc/qtwebview/src/webview/qwebview.cpp
- 構造函數里關聯槽函數和信號
#if ANDROID connect(d, &QAbstractWebView::pdfPrintingFinished, this, &QWebView::onPdfPrintingFinished); #endif
- 實現槽函數printToPdf
#if ANDROID void QWebView::printToPdf(const QString &fileName) { d->printToPdf(fileName); } #endif
- 實現槽函數onPdfPrintingFinished
#if ANDROID void QWebView::onPdfPrintingFinished(bool succeed) { Q_EMIT pdfPrintingFinished(succeed); } #endif
- 在$QtSrc/qtwebview/src/jar目錄下新建lib目錄,將dexmaker-1.2.jar文件拷貝到該目錄下
- 修改$QtSrc/qtwebview/src/jar/jar.pro
TARGET = QtAndroidWebView
load(qt_build_paths)
CONFIG += java
DESTDIR = $$MODULE_BASE_OUTDIR/jar
JAVACLASSPATH += $$PWD/src \
$$PWD/lib/dexmaker-1.2.jar
JAVASOURCES += $$PWD/src/org/qtproject/qt5/android/view/QtAndroidWebViewController.java
# install
thridpartyjar.files = \
$$PWD/lib/dexmaker-1.2.jar
thridpartyjar.path = $$[QT_INSTALL_PREFIX]/jar
target.path = $$[QT_INSTALL_PREFIX]/jar
INSTALLS += target thridpartyjar - 修改$QtSrc/qtwebview/src/webview/webview.pro
…… QMAKE_DOCS = \
$$PWD/doc/qtwebview.qdocconf
ANDROID_BUNDLED_JAR_DEPENDENCIES = \
jar/QtAndroidWebView.jar \
jar/dexmaker-1.2.jar
ANDROID_PERMISSIONS = \
android.permission.ACCESS_FINE_LOCATION
ANDROID_LIB_DEPENDENCIES = \
plugins/webview/libqtwebview_android.so
HEADERS += $$PUBLIC_HEADERS $$PRIVATE_HEADERS
load(qt_module) - 修改$QtSrc/qtwebview/src/imports/plugins.qmltypes
- 增加信號
Signal { name: "pdfPrintingFinished" revision: 1 Parameter { name: "succeed"; type: "bool" } }
- 增加方法
Method { name: "printToPdf" revision: 1 Parameter { name: "fileName"; type: "string" } }
-
配置和編譯
-
./configure -extprefix $QTInstall/android_arm64_v8a -xplatform android-clang -release -nomake tests -nomake examples -opensource -confirm-license -recheck-all -android-ndk $NDKPATH -android-sdk $AndroidSDKPATH -android-ndk-host linux-x86_64 -android-arch arm64-v8a
-android-arch支持armeabi, armeabi-v7a, arm64-v8a, x86, x86_64,一次只能編譯一個架構,註意不同架構要修改安裝目錄
- make -j8
- make install
- 上述軟體版本
- QT:5.13.2
- NDK:r20b(20.1.5948944)
- Android-buildToolsVersion:29.0.2
- 使用示例
import QtQuick 2.12 import QtQuick.Window 2.12 import QtWebView 1.1 import QtQuick.Controls 2.12 Window { id: window visible: true width: 1080 height: 1920 title: qsTr("Hello World") WebView{ id:webView anchors.bottom: printBtn.top anchors.right: parent.right anchors.left: parent.left anchors.top: parent.top anchors.bottomMargin: 0 url:"http://www.qq.com" onPdfPrintingFinished: { printBtn.text = "列印" + (succeed?"成功":"失敗") printBtn.enabled = true } } Button { id:printBtn text: "列印" anchors.bottom: parent.bottom anchors.bottomMargin: 0 onClicked: { printBtn.enabled = false webView.printToPdf("/sdcard/aaa.pdf") } } }
全部修改見https://github.com/ALittleDruid/qtwebview/commit/722a4757dd0acf86846194607a433cd724e9b028
下期預告:在Android平臺上實現串口讀寫的功能