Some devices cannot be supported

app/src/main/java/eu/faircode/email/ActivityMain.java

@@ -22,6 +22,7 @@ package eu.faircode.email;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
+import android.os.Build;
 import android.os.Bundle;
 import android.preference.PreferenceManager;
 
@@ -36,6 +37,13 @@ public class ActivityMain extends AppCompatActivity implements FragmentManager.O
     protected void onCreate(Bundle savedInstanceState) {
         getSupportFragmentManager().addOnBackStackChangedListener(this);
 
+        if (!isSupportedDevice()) {
+            setTheme(R.style.AppThemeLight);
+            super.onCreate(savedInstanceState);
+            setContentView(R.layout.activity_unsupported);
+            return;
+        }
+
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
         prefs.registerOnSharedPreferenceChangeListener(this);
 
@@ -94,4 +102,50 @@ public class ActivityMain extends AppCompatActivity implements FragmentManager.O
             if (prefs.getBoolean(key, false))
                 recreate();
     }
+
+    private boolean isSupportedDevice() {
+        if ("Amazon".equals(Build.BRAND) && Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
+        /*
+            java.lang.IllegalArgumentException: Comparison method violates its general contract!
+            java.lang.IllegalArgumentException: Comparison method violates its general contract!
+            at java.util.TimSort.mergeHi(TimSort.java:864)
+            at java.util.TimSort.mergeAt(TimSort.java:481)
+            at java.util.TimSort.mergeCollapse(TimSort.java:406)
+            at java.util.TimSort.sort(TimSort.java:210)
+            at java.util.TimSort.sort(TimSort.java:169)
+            at java.util.Arrays.sort(Arrays.java:2010)
+            at java.util.Collections.sort(Collections.java:1883)
+            at android.view.ViewGroup$ChildListForAccessibility.init(ViewGroup.java:7181)
+            at android.view.ViewGroup$ChildListForAccessibility.obtain(ViewGroup.java:7138)
+            at android.view.ViewGroup.dispatchPopulateAccessibilityEventInternal(ViewGroup.java:2734)
+            at android.view.View.dispatchPopulateAccessibilityEvent(View.java:5617)
+            at android.view.View.sendAccessibilityEventUncheckedInternal(View.java:5582)
+            at android.view.View.sendAccessibilityEventUnchecked(View.java:5566)
+            at android.view.View.sendAccessibilityEventInternal(View.java:5543)
+            at android.view.View.sendAccessibilityEvent(View.java:5512)
+            at android.view.View.onFocusChanged(View.java:5449)
+            at android.view.View.handleFocusGainInternal(View.java:5229)
+            at android.view.ViewGroup.handleFocusGainInternal(ViewGroup.java:651)
+            at android.view.View.requestFocusNoSearch(View.java:7950)
+            at android.view.View.requestFocus(View.java:7929)
+            at android.view.ViewGroup.requestFocus(ViewGroup.java:2612)
+            at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2657)
+            at android.view.ViewGroup.requestFocus(ViewGroup.java:2613)
+            at android.view.View.requestFocus(View.java:7896)
+            at android.view.View.requestFocus(View.java:7875)
+            at androidx.recyclerview.widget.RecyclerView.recoverFocusFromState(SourceFile:3788)
+            at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep3(SourceFile:4023)
+            at androidx.recyclerview.widget.RecyclerView.dispatchLayout(SourceFile:3652)
+            at androidx.recyclerview.widget.RecyclerView.consumePendingUpdateOperations(SourceFile:1877)
+            at androidx.recyclerview.widget.RecyclerView$w.run(SourceFile:5044)
+            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:781)
+            at android.view.Choreographer.doCallbacks(Choreographer.java:592)
+            at android.view.Choreographer.doFrame(Choreographer.java:559)
+            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:767)
+         */
+            return false;
+        }
+
+        return true;
+    }
 }

app/src/main/res/layout/activity_unsupported.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="12dp">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="12dp"
+        android:text="@string/app_crash"
+        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
+        android:textColor="?colorWarning"
+        android:textStyle="bold"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/values/strings.xml

@@ -4,6 +4,7 @@
     <string name="app_welcome">FairEmail is an open source email app focused on privacy and security. For this reason some features might work differently from what you are used to.</string>
     <string name="app_limitations">For example, messages will always be reformatted to remove unsafe elements and to improve readability and opening links needs to be confirmed for safety.</string>
     <string name="app_eula" translatable="false">THIS SOFTWARE IS PROVIDED BY THE AUTHOR \'\'AS IS\'\' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.</string>
+    <string name="app_crash">FairEmail is not supported on this device because bugs in Android causes crashes</string>
 
     <string name="channel_service">Service</string>
     <string name="channel_notification">Notifications</string>