java - Input event app issues -
i'm working through input event app. app has textfield , button. information entered sent receiver app handles action , must able write textview in main activity. explanation not confusing.
this built main app from: http://developer.android.com/guide/topics/ui/ui-events.html
this built receiver from: http://developer.android.com/training/sharing/receive.html
the main app loads layout blank. receiver crashes on load. can't figure out why, assistance appreciated.
mainactivity.java (main app)
package com.miller.main; import java.util.list; import android.app.activity; import android.content.intent; import android.content.pm.packagemanager; import android.content.pm.resolveinfo; import android.os.bundle; import android.util.log; import android.view.view; import android.view.view.onclicklistener; import android.widget.button; public class mainactivity extends activity { protected void oncreate(bundle savedinstancestate, bundle savedvalues) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); // capture our button layout final button button = (button)findviewbyid(r.id.corky); onclicklistener mcorkylistener = null; // register onclick listener implementation above button.setonclicklistener(mcorkylistener); // create anonymous implementation of onclicklistener @suppresswarnings("unused") onclicklistener mcorkylistener1 = new onclicklistener() { @suppresswarnings("null") public void onclick(view v) { // when button clicked // capture our button layout button.setonclicklistener(this); intent sendintent = new intent(); sendintent.setaction(intent.action_send); sendintent.putextra(intent.extra_text, "this text send."); sendintent.settype("text/plain"); packagemanager packagemanager = getpackagemanager(); intent intent = null; list<resolveinfo> activities = packagemanager.queryintentactivities(intent, 0); boolean isintentsafe = activities.size() > 0; intent.setflags(intent.flag_activity_new_task | intent.flag_activity_clear_top); startactivity(sendintent); } }; } @override protected void onpause() { log.w("monday", "paused"); super.onpause(); log.w("monday", "paused"); // activity taking focus (this activity "paused"). } @override protected void onstop() { log.w("tuesday", "stopped"); super.onstop(); log.w("tuesday", "stopped"); // activity no longer visible (it "stopped") } } activity_main.xml (main app)
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingbottom="@dimen/activity_vertical_margin" android:paddingleft="@dimen/activity_horizontal_margin" android:paddingright="@dimen/activity_horizontal_margin" android:paddingtop="@dimen/activity_vertical_margin" tools:context="com.miller.main.mainactivity" > <edittext android:id="@+id/text_field" android:layout_width="wrap_content" android:layout_height="wrap_content" android:hint="@string/text_field" android:inputtype="text" /> <button android:id="@+id/corky" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/button_text" android:layout_below="@+id/text_field" /> </relativelayout> mainactivity.java (receiver app)
package com.miller.receiver; import java.util.arraylist; import android.app.activity; import android.content.intent; import android.net.uri; import android.os.bundle; public class mainactivity extends activity { @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); } // intent, action , mime type intent intent = getintent(); string action = intent.getaction(); string type = intent.gettype(); { if (intent.action_send.equals(action) && type != null) { if ("text/plain".equals(type)) { handlesendtext(intent); // handle text being sent } else if (type.startswith("image/")) { handlesendimage(intent); // handle single image being sent } } else if (intent.action_send_multiple.equals(action) && type != null) { if (type.startswith("image/")) { handlesendmultipleimages(intent); // handle multiple images being sent } } else { // handle other intents, such being started home screen } } void handlesendtext(intent intent) { string sharedtext = intent.getstringextra(intent.extra_text); if (sharedtext != null) { // update ui reflect text being shared } } void handlesendimage(intent intent) { uri imageuri = (uri) intent.getparcelableextra(intent.extra_stream); if (imageuri != null) { // update ui reflect image being shared } } void handlesendmultipleimages(intent intent) { arraylist<uri> imageuris = intent.getparcelablearraylistextra(intent.extra_stream); if (imageuris != null) { // update ui reflect multiple images being shared } } } activity_main.xml receiver app default @ moment.
logcat receiver app
04-09 15:41:11.244: e/androidruntime(1114): fatal exception: main 04-09 15:41:11.244: e/androidruntime(1114): process: com.miller.receiver, pid: 1114 04-09 15:41:11.244: e/androidruntime(1114): java.lang.runtimeexception: unable instantiate activity componentinfo{com.miller.receiver/com.miller.receiver.mainactivity}: java.lang.nullpointerexception 04-09 15:41:11.244: e/androidruntime(1114): @ android.app.activitythread.performlaunchactivity(activitythread.java:2121) 04-09 15:41:11.244: e/androidruntime(1114): @ android.app.activitythread.handlelaunchactivity(activitythread.java:2245) 04-09 15:41:11.244: e/androidruntime(1114): @ android.app.activitythread.access$800(activitythread.java:135) 04-09 15:41:11.244: e/androidruntime(1114): @ android.app.activitythread$h.handlemessage(activitythread.java:1196) 04-09 15:41:11.244: e/androidruntime(1114): @ android.os.handler.dispatchmessage(handler.java:102) 04-09 15:41:11.244: e/androidruntime(1114): @ android.os.looper.loop(looper.java:136) 04-09 15:41:11.244: e/androidruntime(1114): @ android.app.activitythread.main(activitythread.java:5017) 04-09 15:41:11.244: e/androidruntime(1114): @ java.lang.reflect.method.invokenative(native method) 04-09 15:41:11.244: e/androidruntime(1114): @ java.lang.reflect.method.invoke(method.java:515) 04-09 15:41:11.244: e/androidruntime(1114): @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:779) 04-09 15:41:11.244: e/androidruntime(1114): @ com.android.internal.os.zygoteinit.main(zygoteinit.java:595) 04-09 15:41:11.244: e/androidruntime(1114): @ dalvik.system.nativestart.main(native method) 04-09 15:41:11.244: e/androidruntime(1114): caused by: java.lang.nullpointerexception 04-09 15:41:11.244: e/androidruntime(1114): @ com.miller.receiver.mainactivity.<init>(mainactivity.java:20) 04-09 15:41:11.244: e/androidruntime(1114): @ java.lang.class.newinstanceimpl(native method) 04-09 15:41:11.244: e/androidruntime(1114): @ java.lang.class.newinstance(class.java:1208) 04-09 15:41:11.244: e/androidruntime(1114): @ android.app.instrumentation.newactivity(instrumentation.java:1061) 04-09 15:41:11.244: e/androidruntime(1114): @ android.app.activitythread.performlaunchactivity(activitythread.java:2112) 04-09 15:41:11.244: e/androidruntime(1114): ... 11 more