Online graphical editor

Online graphic editor:

https://sketch.io/sketchpad/

Gives a possibility to create very nice vector graphic images, has a large library of sampled objects.

Xamarin: Right-bottom button over the controls

If you're finding a way how to design a buton over the controls, it looks like this:

    <ContentPage.Content>
    <RelativeLayout>
      <Grid>
        <Grid.RowDefinitions>
          <RowDefinition Height="30" />
          <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
          <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <Grid.Triggers>
          <DataTrigger TargetType="Grid" Binding="{Binding IsBusy}" Value="True">
            <Setter Property="IsVisible" Value="False" />
          </DataTrigger>
        </Grid.Triggers>
        <StackLayout 
                Grid.Row="0"
                Grid.Column="0">
          <Label Text="List"
                       FontAttributes="Bold"
                       FontSize="Large"
                       VerticalOptions="Start"
                       HorizontalOptions="Center"
                       Margin="0, 0, 0, 0" />
        </StackLayout>
        <StackLayout 
                Grid.Row="1"
                Grid.Column="0"
                Margin="10">
          <ListView
                    x:Name="list"
                    ItemsSource="{Binding List}"
                    IsVisible="True"
                    SeparatorVisibility="Default"
                    HasUnevenRows="true"
                    ItemTapped="List_ItemTapped"
                    SelectionMode="Single">
            <ListView.ItemTemplate>
              <DataTemplate>
                <ViewCell>
                  <StackLayout
                                    x:Name="Item"
                                    Orientation="Horizontal"
                                    HeightRequest="190"
                                    >
                    
                    <StackLayout.GestureRecognizers>
                      <TapGestureRecognizer
                                            NumberOfTapsRequired="1"
                                            Tapped="Item_TapGestureRecognizer_Tapped_1"
                                            CommandParameter="{Binding Source={x:Reference Item}, Path=BindingContext}"
                                        />
                    </StackLayout.GestureRecognizers>
                  </StackLayout>
                </ViewCell>
              </DataTemplate>
            </ListView.ItemTemplate>
          </ListView>
          <Label Text="Brak kart w aplikacji"
                       VerticalOptions="CenterAndExpand"
                       HorizontalOptions="CenterAndExpand"
                       IsVisible="{Binding IsEmpty}"
                       />
        </StackLayout>
        <ContentView Grid.Row="0"
                         Grid.Column="0"
                         IsVisible="{Binding IsBusy}"
                         BackgroundColor="#222222" 
                         Opacity="0.5"
                         AbsoluteLayout.LayoutFlags="All"
                         AbsoluteLayout.LayoutBounds="0,0,1,1"
                         >
          <ActivityIndicator IsRunning="True"
                        Color="{StaticResource ButtonBackgroundColor}"
                        VerticalOptions="CenterAndExpand"
                        HorizontalOptions="CenterAndExpand" />
        </ContentView>
        
      </Grid>
      <RelativeLayout x:Name="PlusButton" 
                        WidthRequest="100"
                        HeightRequest="100"
                        HorizontalOptions="End" 
                        VerticalOptions="End"                      
                        RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent, Property=Y, Factor=0,Constant=0}"
                        RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent, Property=X, Factor=1, Constant=0}"
                        RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1,Constant=0}"
                        RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width,Factor=1,Constant=0}"
                          >
        <ImageButton                             
                        Source="plus.png"
                        BackgroundColor="Transparent"
                        Clicked="PlusButton_Clicked"
                    />
      </RelativeLayout>
    </RelativeLayout>
  </ContentPage.Content>
</ContentPage>

Bold is actually that RelativeLayout with the plus Image (buton). If you'd like to move the buton somewhere else, you have to change Factor value.

Helpful adb commands (How to stop an Android Emulator from Command Line)

Find adb.exe on your computer.

You have to use

adb kill-server

or

adb -s emulator-5554 emu kill

, where

emulator-5554

is the emulator name.

For Ubuntu users:

adb devices | grep emulator | cut -f1 | while read line; do adb -s $line emu kill; done

# Fully Uninstall an app on an emulator:

adb shell "pm uninstall <your packet name, f.e. com.nl.hello.world>"

# Uninstall an app on an emulator with the local data saving:

adb shell "pm uninstall -k <your packet name, f.e. com.nl.hello.world>"

# Install a previously copied app on an emulator:

adb shell "pm install -r /storage/00BC-1AFD/temp/v1.0/<your packet name, f.e. com.nl.hello.world>.apk"

# restart adb to be able to use device via WiFi

 adb kill-server &&  adb start-server && adb tcpip 5555 && adb connect 192.168.0.14:5555

# How do I find out which keystore was used to sign an app?:

First, unzip the APK and extract the file /META-INF/ANDROID_.RSA (this file may also be CERT.RSA, but there should only be one .RSA file).

cd "c:\Program Files (x86)\Android\android-sdk\platform-tools\"

keytool -printcert -file ANDROID_.RSA

# Then use the keytool again to print out all the aliases of your signing keystore:

cd "c:\Program Files (x86)\Android\android-sdk\platform-tools\"

keytool -list -keystore my-signing-key.keystore