create crash report files in debug version

app/src/main/AndroidManifest.xml

@@ -41,6 +41,7 @@
                 android:protectionLevel="signature" />
 
     <application android:label="@string/english_ime_name"
+            android:name="org.dslul.openboard.inputmethod.latin.App"
             android:icon="@mipmap/ic_launcher"
             android:roundIcon="@mipmap/ic_launcher_round"
             android:supportsRtl="true"

app/src/main/java/org/dslul/openboard/inputmethod/latin/App.kt

@@ -0,0 +1,56 @@
+package org.dslul.openboard.inputmethod.latin
+
+import android.app.Application
+import android.content.Context
+import android.os.Build
+import java.io.File
+import java.io.IOException
+import java.io.PrintWriter
+import java.io.StringWriter
+import java.util.*
+
+class App : Application() {
+    override fun onCreate() {
+        super.onCreate()
+        if (BuildConfig.DEBUG) {
+            CrashReportExceptionHandler(applicationContext).install()
+        }
+    }
+}
+
+// basically copied from StreetComplete
+private class CrashReportExceptionHandler(val appContext: Context) : Thread.UncaughtExceptionHandler {
+    private var defaultUncaughtExceptionHandler: Thread.UncaughtExceptionHandler? = null
+
+    fun install(): Boolean {
+        val ueh = Thread.getDefaultUncaughtExceptionHandler()
+        check(ueh !is CrashReportExceptionHandler) { "May not install several CrashReportExceptionHandlers!" }
+        defaultUncaughtExceptionHandler = ueh
+        Thread.setDefaultUncaughtExceptionHandler(this)
+        return true
+    }
+
+    override fun uncaughtException(t: Thread, e: Throwable) {
+        val stackTrace = StringWriter()
+
+        e.printStackTrace(PrintWriter(stackTrace))
+        writeCrashReportToFile("""
+Thread: ${t.name}
+App version: ${BuildConfig.VERSION_NAME}
+Device: ${Build.BRAND} ${Build.DEVICE}, Android ${Build.VERSION.RELEASE}
+Locale: ${Locale.getDefault()}
+Stack trace:
+$stackTrace
+""")
+        defaultUncaughtExceptionHandler!!.uncaughtException(t, e)
+    }
+
+    private fun writeCrashReportToFile(text: String) {
+        try {
+            val dir = appContext.getExternalFilesDir(null) ?: return
+            val crashReportFile = File(dir, "crash_report_${System.currentTimeMillis()}.txt")
+            crashReportFile.writeText(text)
+        } catch (ignored: IOException) {
+        }
+    }
+}

app/src/main/java/org/dslul/openboard/inputmethod/latin/common/FileUtils.java

@@ -21,6 +21,7 @@ import java.io.FileOutputStream;
 import java.io.FilenameFilter;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 
 /**
  * A simple class to help with removing directories recursively.
@@ -68,6 +69,10 @@ public class FileUtils {
             throw new IOException("could not create parent folder");
         }
         FileOutputStream out = new FileOutputStream(outfile);
+        copyStreamToOtherStream(in, out);
+    }
+
+    public static void copyStreamToOtherStream(InputStream in, OutputStream out) throws IOException {
         byte[] buf = new byte[1024];
         int len;
         while ((len = in.read(buf)) > 0) {

app/src/main/java/org/dslul/openboard/inputmethod/latin/settings/SettingsFragment.java

@@ -18,7 +18,9 @@ package org.dslul.openboard.inputmethod.latin.settings;
 
 import android.app.ActionBar;
 import android.app.Activity;
+import android.app.AlertDialog;
 import android.content.Intent;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.preference.Preference;
@@ -28,12 +30,23 @@ import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
 
+import org.dslul.openboard.inputmethod.latin.BuildConfig;
 import org.dslul.openboard.inputmethod.latin.R;
+import org.dslul.openboard.inputmethod.latin.common.FileUtils;
 import org.dslul.openboard.inputmethod.latin.utils.ApplicationUtils;
 import org.dslul.openboard.inputmethod.latin.utils.FeedbackUtils;
 import org.dslul.openboard.inputmethod.latin.utils.JniUtils;
 import org.dslul.openboard.inputmethodcommon.InputMethodSettingsFragment;
 
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
 public final class SettingsFragment extends InputMethodSettingsFragment {
     // We don't care about menu grouping.
     private static final int NO_MENU_GROUP = Menu.NONE;
@@ -41,6 +54,9 @@ public final class SettingsFragment extends InputMethodSettingsFragment {
     private static final int MENU_ABOUT = Menu.FIRST;
     // The second menu item id and order.
     private static final int MENU_HELP_AND_FEEDBACK = Menu.FIRST + 1;
+    private static final int CRASH_REPORT_REQUEST_CODE = 985287532;
+    // for storing crash report files, so onActivityResult can actually use them
+    private final ArrayList<File> crashReportFiles = new ArrayList<>();
 
     @Override
     public void onCreate(final Bundle icicle) {
@@ -67,6 +83,8 @@ public final class SettingsFragment extends InputMethodSettingsFragment {
         if (actionBar != null && screenTitle != null) {
             actionBar.setTitle(screenTitle);
         }
+        if (BuildConfig.DEBUG)
+            askAboutCrashReports();
     }
 
     @Override
@@ -110,4 +128,64 @@ public final class SettingsFragment extends InputMethodSettingsFragment {
         }
         return Secure.getInt(activity.getContentResolver(), "user_setup_complete", 0) != 0;
     }
+
+    private void askAboutCrashReports() {
+        // find crash report files
+        final File dir = getActivity().getExternalFilesDir(null);
+        if (dir == null) return;
+//        final File[] files = dir.listFiles((file, s) -> file.getName().startsWith("crash_report"));
+        final File[] allFiles = dir.listFiles();
+        if (allFiles == null) return;
+        crashReportFiles.clear();
+        for (File file : allFiles) {
+            if (file.getName().startsWith("crash_report"))
+                crashReportFiles.add(file);
+        }
+        if (crashReportFiles.isEmpty()) return;
+        new AlertDialog.Builder(getActivity())
+                .setMessage("Crash report files found")
+                .setPositiveButton("get", (dialogInterface, i) -> {
+                    final Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
+                    intent.addCategory(Intent.CATEGORY_OPENABLE);
+                    intent.putExtra(Intent.EXTRA_TITLE, "crash_reports.zip");
+                    intent.setType("application/zip");
+                    startActivityForResult(intent, CRASH_REPORT_REQUEST_CODE);
+                })
+                .setNeutralButton("delete", (dialogInterface, i) -> {
+                    for (File file : crashReportFiles) {
+                        file.delete(); // don't care whether it fails, though user will complain
+                    }
+                })
+                .setNegativeButton("ignore", null)
+                .show();
+    }
+
+    @Override
+    public void onActivityResult(int requestCode, int resultCode, Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+        if (resultCode != Activity.RESULT_OK || data == null) return;
+        if (requestCode != CRASH_REPORT_REQUEST_CODE) return;
+        if (crashReportFiles.isEmpty()) return;
+        final Uri uri = data.getData();
+        if (uri == null) return;
+        final OutputStream os;
+        try {
+            os = getActivity().getContentResolver().openOutputStream(uri);
+            final BufferedOutputStream bos = new BufferedOutputStream(os);
+            final ZipOutputStream z = new ZipOutputStream(bos);
+            for (File file : crashReportFiles) {
+                FileInputStream f = new FileInputStream(file);
+                z.putNextEntry(new ZipEntry(file.getName()));
+                FileUtils.copyStreamToOtherStream(f, z);
+                f.close();
+                z.closeEntry();
+            }
+            z.close();
+            bos.close();
+            os.close();
+            for (File file : crashReportFiles) {
+                file.delete();
+            }
+        } catch (IOException ignored) { }
+    }
 }