java - How to select a PDF file using startActivityForResult intent and return result in a second class -
i relatively new android programming, want create pdf reader calls inbuilt file manager select pdf file , display pdf file in second class. here code far still having issues, think second activity unable selected pdf file , unable fix error
mainactivity package com.example.user.projectapp; import android.app.activity; import android.app.listactivity; import android.content.context; import android.content.intent; import android.database.cursor; import android.net.uri; import android.provider.openablecolumns; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.util.log; import android.view.view; import android.widget.arrayadapter; import android.widget.listview; import java.io.file; import java.io.ioexception; import java.io.inputstream; import java.net.uri; import java.net.urisyntaxexception; import java.util.arraylist; import java.util.collections; import java.util.list; public class mainactivity extends appcompatactivity { public static string path; private static final int pickfile_request_code = 0; file tempfile; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); getfile(); } public void getfile() { intent intent = new intent(intent.action_get_content); intent.settype("application/pdf"); path = intent.getstringextra("path"); intent.putextra("path",path); startactivityforresult(intent, pickfile_request_code); } second activity package com.example.user.projectapp; import android.annotation.targetapi; import android.content.intent; import android.graphics.bitmap; import android.graphics.pdf.pdfrenderer; import android.os.build; import android.os.environment; import android.os.parcelfiledescriptor; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.view.view; import android.widget.button; import android.widget.imageview; import java.io.file; public class main2activity extends appcompatactivity { int pagecount = -1; button buttonnext, buttonprevious; imageview imageview; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main2); buttonnext = (button) findviewbyid(r.id.button1); buttonprevious = (button) findviewbyid(r.id.button2); imageview = (imageview) findviewbyid(r.id.imageview); buttonnext.setonclicklistener(new view.onclicklistener() { @override public void onclick(view view) { pagecount++; render(); } }); buttonprevious.setonclicklistener(new view.onclicklistener() { @override public void onclick(view view) { pagecount--; render(); } }); } @targetapi(build.version_codes.lollipop) public void render() { try { int width = imageview.getwidth(); int height = imageview.getheight(); bitmap bitmap = bitmap.createbitmap(width, height, bitmap.config.argb_4444); intent intent = getintent(); string data = intent.getstringextra("path"); file file = new file(data); pdfrenderer renderer = new pdfrenderer(parcelfiledescriptor.open(file, parcelfiledescriptor.mode_read_only)); if (pagecount < 0) { pagecount = 0; } else if (pagecount > renderer.getpagecount()) { pagecount = renderer.getpagecount() - 1; } renderer.openpage(pagecount).render(bitmap, null, null, pdfrenderer.page.render_mode_for_display); imageview.setimagebitmap(bitmap); imageview.invalidate(); } catch (exception e) { e.printstacktrace(); } } @override public void onbackpressed() { super.onbackpressed(); intent intent = new intent(this, mainactivity.class); startactivity(intent); } } and logcat gives
03-28 17:19:33.387 2492-2492/com.example.user.projectapp w/system.err: java.lang.nullpointerexception: attempt invoke virtual method 'char[] java.lang.string.tochararray()' on null object reference 03-28 17:19:33.400 2492-2492/com.example.user.projectapp w/system.err: @ java.io.file.fixslashes(file.java:185) 03-28 17:19:33.400 2492-2492/com.example.user.projectapp w/system.err: @ java.io.file.<init>(file.java:134) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ com.example.user.projectapp.main2activity.render(main2activity.java:69) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ com.example.user.projectapp.main2activity$1.onclick(main2activity.java:42) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ android.view.view.performclick(view.java:4764) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ android.view.view$performclick.run(view.java:19844) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ android.os.handler.handlecallback(handler.java:739) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ android.os.handler.dispatchmessage(handler.java:95) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ android.os.looper.loop(looper.java:135) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ android.app.activitythread.main(activitythread.java:5351) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ java.lang.reflect.method.invoke(native method) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ java.lang.reflect.method.invoke(method.java:372) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:908) 03-28 17:19:33.401 2492-2492/com.example.user.projectapp w/system.err: @ com.android.internal.os.zygoteinit.main(zygoteinit.java:703) code modified based on 1 activity only...... yet onactivityresult not return result,
file myfile; public static string result; public string path; private static final int pickfile_request_code = 12; int pagecount = -1; button buttonnext, buttonprevious; imageview imageview; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); getfile(); buttonnext = (button) findviewbyid(r.id.button1); buttonprevious = (button) findviewbyid(r.id.button2); imageview = (imageview) findviewbyid(r.id.imageview); buttonnext.setonclicklistener(new view.onclicklistener() { @override public void onclick(view view) { pagecount++; render(); } }); buttonprevious.setonclicklistener(new view.onclicklistener() { @override public void onclick(view view) { pagecount--; render(); } }); } public void getfile() { intent intent = new intent(intent.action_get_content); intent.settype("application/pdf"); //intent.settype("image/"); // path = intent.getstringextra("path"); //intent.putextra("path",path); //intent.addcategory(intent.category_openable); startactivityforresult(intent, 12); } @override protected void onactivityresult(int requestcode, int resultcode, intent data) { super.onactivityresult(requestcode, resultcode, data); if (requestcode==12){ if (data != null){ toast.maketext(this,"file selected",toast.length_long).show(); // result=data.getstringextra("data"); uri uri=data.getdata(); // string uristring = uri.tostring(); myfile = new file(uri.tostring()); path = myfile.getabsolutepath(); // result=data.tostring(); // uri uri=data.getparcelableextra(path); // path=fileuri.tostring(); this.render(); } } } @targetapi(build.version_codes.lollipop) public void render() { try { int width = imageview.getwidth(); int height = imageview.getheight(); bitmap bitmap = bitmap.createbitmap(width, height, bitmap.config.argb_4444); //intent intent = getintent(); //string path = intent.getstringextra("path"); // uri uri = uri.parse(uri_str); file file = new file(path); //file storage = environment.getexternalstoragedirectory(); // intent.setflags(intent.flag_activity_reorder_to_front); pdfrenderer renderer = new pdfrenderer(parcelfiledescriptor.open(file, parcelfiledescriptor.mode_read_only)); if (pagecount < 0) { pagecount = 0; } else if (pagecount > renderer.getpagecount()) { pagecount = renderer.getpagecount() - 1; } // matrix m = imageview.getimagematrix(); // rect rect=new rect(0,0,width,height); renderer.openpage(pagecount).render(bitmap, null, null, pdfrenderer.page.render_mode_for_display); //imageview.setimagematrix(m); imageview.setimagebitmap(bitmap); imageview.invalidate(); } catch (exception e) { e.printstacktrace(); } } } and logcat error...
03-29 11:32:47.276 21674-21674/com.example.user.newtry w/system.err: java.io.filenotfoundexception: no such file or directory 03-29 11:32:47.283 21674-21674/com.example.user.newtry w/system.err: @ android.os.parcel.openfiledescriptor(native method) 03-29 11:32:47.283 21674-21674/com.example.user.newtry w/system.err: @ android.os.parcelfiledescriptor.openinternal(parcelfiledescriptor.java:253) 03-29 11:32:47.283 21674-21674/com.example.user.newtry w/system.err: @ android.os.parcelfiledescriptor.open(parcelfiledescriptor.java:199)
yes.. because path null.. reason getting null pointer exception
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