Android handling of application crashes due to no exception handling

Everyone in the debugging process, often encounter inexplicable program crashes, then how should we look at the details of these crashes?

By Baidu, there are the following methods:

The first is to write two classes

Crashapplication

Package Com.example.endtwo;import android.app.Application;    public class Crashapplication extends application {      @Override public      void OnCreate () {          super.oncreate ();          Crashhandler Crashhandler = Crashhandler.getinstance ();          Crashhandler.init (Getapplicationcontext ());      }  }  

Crashhandler

Package Com.example.endtwo;import Java.io.file;import Java.io.fileoutputstream;import java.io.PrintWriter;import Java.io.stringwriter;import Java.io.writer;import Java.lang.thread.uncaughtexceptionhandler;import Java.lang.reflect.field;import Java.text.dateformat;import Java.text.simpledateformat;import java.util.Date; Import Java.util.hashmap;import java.util.map;import Android.content.context;import android.content.pm.PackageInfo ; Import Android.content.pm.packagemanager;import Android.content.pm.packagemanager.namenotfoundexception;import Android.os.build;import Android.os.environment;import Android.os.looper;import Android.util.Log;import android.widget.toast;/** * Uncaughtexception processing class, when the program occurs uncaught exception, there is the class to take over the program, and record send error report. * * @author User * */public class Crashhandler implements Uncaughtexceptionhandler {public static final String TAG = "Cr Ashhandler ";//system default Uncaughtexception processing class private Thread.uncaughtexceptionhandler mdefaulthandler;// Crashhandler instance private static Crashhandler instance = new Crashhandler ();//Program Context object private context mcontext;//used to store device information and exception information private map<string, string> Infos = new hashmap<string, string> ();//used to format the date as part of the log file name private DateFormat formatter = new SimpleDateFormat (" Yyyy-mm-dd-hh-mm-ss ");/** guarantee only one Crashhandler instance */private Crashhandler () {}/** Get Crashhandler instance, Singleton mode */public static Crashhandler getinstance () {return INSTANCE;} /** * Initialize * * @param context */public void init (context context) {Mcontext = context;//get system default Uncaughtexception processor Mdefaul Thandler = Thread.getdefaultuncaughtexceptionhandler ();// Set the Crashhandler as the program's default processor Thread.setdefaultuncaughtexceptionhandler (this);} /** * When uncaughtexception occurs, it is transferred to the function to process */@Overridepublic void uncaughtexception (thread thread, Throwable ex) {if (! HandleException (ex) && Mdefaulthandler! = null) {//If the user does not handle it, let the system default exception handler handle the Mdefaulthandler.uncaughtexception (thread, ex);} else {try {thread.sleep,} catch (Interruptedexception e) {log.e (TAG, "error:", e);} Exit Program ANDROID.OS.PRocess.killprocess (Android.os.Process.myPid ()); System.exit (1);}} /** * Custom error handling, collect error messages to send error reports, etc. are done here. * * @param ex * @return true: Returns False if the exception information is processed; */private boolean handleexception (Throwable ex) {if (ex = = null) {return false;} Use Toast to display exception information new Thread () {@Overridepublic void run () {looper.prepare (); Toast.maketext (Mcontext, "Sorry, the program has an exception and is about to exit.", Toast.length_long). Show (); Looper.loop ();}}. Start ();//Collect equipment parameter information collectdeviceinfo (mcontext);//Save log file Savecrashinfo2file (ex); return true;} /** * Collect device parameter information * @param ctx */public void Collectdeviceinfo (Context ctx) {try {packagemanager pm = Ctx.getpackagemanager () ; PackageInfo pi = pm.getpackageinfo (Ctx.getpackagename (), packagemanager.get_activities); if (pi! = null) {String Versionname = Pi.versionname = = null? "NULL": Pi.versionname; String Versioncode = Pi.versioncode + ""; Infos.put ("Versionname", Versionname); Infos.put ("Versioncode", VersionCode);}} catch (Namenotfoundexception e) {log.e (TAG, "An error occured if collect package info", e);}field[] fields = Build.class.getDeclaredFields (), for (Field field:fields) {try {field.setaccessible (true); Infos.put ( Field.getname (), Field.get (null). ToString ()); LOG.D (TAG, Field.getname () + ":" + field.get (null));} catch (Exception e) {log.e (TAG, "An error occured when collect crash info", e);}} /** * Save error message to file * * @param ex * @return return file name for easy Transfer of file to server */private String Savecrashinfo2file (Throwable ex) {Stringbuffe R sb = new StringBuffer (); for (map.entry<string, string> entry:infos.entrySet ()) {String key = Entry.getkey (); String value = Entry.getvalue (); Sb.append (key + "=" + value + "\ n");} Writer writer = new StringWriter (); PrintWriter printwriter = new PrintWriter (writer); Ex.printstacktrace (PrintWriter); Throwable cause = Ex.getcause (); while (cause! = null) {cause.printstacktrace (printwriter); cause = Cause.getcause ();} Printwriter.close (); String result = Writer.tostring (); Sb.append (result); try {long timestamp = System.currenttimemillis (); String time = Formatter.format (new DAte ()); String fileName = "crash-" + Time + "-" + timestamp + ". Log"; if (Environment.getexternalstoragestate (). Equals (Environment. media_mounted) {String path = "/sdcard/crash/"; File dir = new file (path), if (!dir.exists ()) {dir.mkdirs ();} FileOutputStream fos = new FileOutputStream (path + fileName), Fos.write (Sb.tostring (). GetBytes ()); Fos.close (); return fileName;} catch (Exception e) {log.e (TAG, "An error occured while writing file ...", e);} return null;}}

Because this involves writing to a file, add a permission to the Androidmanifest.xml file:

<uses-permission android:name= "Android.permission.WRITE_EXTERNAL_STORAGE"/>

and add the following sentence to the application:

<application         android:name= ". Crashapplication "

This way, if the program crashes, you can look for the generated error file under the crash folder.

Android handling of application crashes due to no exception handling