android实现pdf打印,[NativeScript中用于PDF打印的Android实现
在我的NativeScript-Vue应用程序中，我需要将PDF文档打印到蓝牙打印机上，并接收回调，无论打印成功还是取消。插件nativescript-printer在iOS上可以完美处理，但在Android上不会返回回调(the feature is not implemented)。该插件使用PrintHelper类，该类具有一个回调，该回调在成功和取消时都会被调用，没有参数和返回值。
似乎唯一的解决方案是通过类PrintManager实现打印。一些来源：
所以这就是我尝试过的。 onWrite和onLayout有效，但是onStart和onFinish(这是我的目标)从未调用过。import * as application from "tns-core-modules/application";
function printPdf(pdfFilePath) { // path: "/data/user/0/com.myapp.test/cache/pdf/document1.pdf"
let printManager = application.android.foregroundActivity.getSystemService(android.content.Context.PRINT_SERVICE);
let jobName = "PrintPdf";
let PrintPDFAdapter = android.print.PrintDocumentAdapter.extend({
onStart() {
console.log("on start);
},
onWrite(pages, destination, cancellationSignal, callback) {
let input;
let output;
try {
input = new java.io.FileInputStream(new java.io.File(pdfFilePath));
output = new java.io.FileOutputStream(destination.getFileDescriptor());
let buf = new Array.create("byte", 1024);
let bytesRead;
while ((bytesRead = input.read(buf)) > 0) {
output.write(buf, 0, bytesRead);
}
callback.onWriteFinished(new android.print.PageRange(0, 0));
} catch (e){
console.error(e);
} finally {
try {
input.close();
output.close();
} catch (e) {
console.error(e);
}
}
},
onLayout(oldAttributes, newAttributes, cancellationSignal, callback, extras){
try {
if (cancellationSignal.isCanceled()) {
callback.onLayoutCancelled();
return;
}
let pdi = new android.print.PrintDocumentInfo.Builder("print_output.pdf").setContentType(android.print.PrintDocumentInfo.CONTENT_TYPE_DOCUMENT).build();
callback.onLayoutFinished(pdi, true);
} catch (e) {
console.error(e);
}
},
onFinish() {
console.log("on finish");
}
});
let pda = new PrintPDFAdapter();
printManager.print(jobName, pda, null);
}