java

This post shows a way to use the CLIM library inside an Android app.

The problem

We’d like to use a simple activity with an EditText (maybe multiline) as output and another EditText as input. Since the CLIM’s engine use Standard input/output streams as default, we need to implement our custom ones.

The Layout

The layout of our activity will consists on:

Multiline EditText etout as output
EditText etin as input
Button btnok to commit the input (equivalent to ENTER key)

The activity_main.xml :

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/etout"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="8dp"
        android:gravity="top|left"
        android:inputType="textMultiLine"
        android:lines="200"
        android:minLines="10"
        android:scrollbars="vertical"
        app:layout_constraintBottom_toTopOf="@+id/etin"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:clickable="false"
        android:cursorVisible="false"
        android:focusable="false"
        android:focusableInTouchMode="false"
        />

    <EditText
        android:id="@+id/etin"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginBottom="8dp"
        android:ems="10"
        android:text=""
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/btnok"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:id="@+id/btnok"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:text="ok"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

<?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"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context=".MainActivity">

<EditText

android:id="@+id/etout"

android:layout_width="match_parent"

android:layout_height="0dp"

android:layout_marginStart="8dp"

android:layout_marginEnd="8dp"

android:gravity="top|left"

android:inputType="textMultiLine"

android:lines="200"

android:minLines="10"

android:scrollbars="vertical"

app:layout_constraintBottom_toTopOf="@+id/etin"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toTopOf="parent"

android:clickable="false"

android:cursorVisible="false"

android:focusable="false"

android:focusableInTouchMode="false"

<EditText

android:id="@+id/etin"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginStart="8dp"

android:layout_marginBottom="8dp"

android:ems="10"

android:text=""

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintEnd_toStartOf="@+id/btnok"

app:layout_constraintStart_toStartOf="parent" />

<Button

android:id="@+id/btnok"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginEnd="8dp"

android:layout_marginBottom="8dp"

android:text="ok"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintEnd_toEndOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

CLIM dependency

First things first: let’s add dependancy to CLIM in the gradle project-level build.gradle :

allprojects {
    repositories {
        google()
        jcenter()
        maven {
            url  "https://dl.bintray.com/ianovir/CLIM"
        }
    }
}

allprojects {

repositories {

google()

jcenter()

maven {

url "https://dl.bintray.com/ianovir/CLIM"

}

then the app-level build.gradle:

dependencies {
    ...
    implementation 'com.ianovir.clim:CLIM:1.1'

}

dependencies {

...

implementation 'com.ianovir.clim:CLIM:1.1'

}

The Activity

Inside our activity we will prepare our CLIM engine:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    launchClim();
}

private void launchClim() {
	Engine engine = new Engine("CLIM DEMO");
	Menu mainMenu = engine.buildMenu("Control Console");

	mainMenu.addEntry(new Entry("access security") {
		@Override
		public void onAction() {
		}
	});

	mainMenu.addEntry(new Entry("access security grid") {
		@Override
		public void onAction() {
		}
	});

	mainMenu.addEntry(new Entry("access main security grid") {
		@Override
		public void onAction() {
		}
	});

	//configure our custom streams:
	prepareStreams(engine);

	engine.addOnTop(mainMenu);
        engine.start();
}

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

launchClim();

}

private void launchClim() {

Engine engine = new Engine("CLIM DEMO");

Menu mainMenu = engine.buildMenu("Control Console");

mainMenu.addEntry(new Entry("access security") {

@Override

public void onAction() {

}

});

mainMenu.addEntry(new Entry("access security grid") {

@Override

public void onAction() {

}

});

mainMenu.addEntry(new Entry("access main security grid") {

@Override

public void onAction() {

}

});

//configure our custom streams:

prepareStreams(engine);

engine.addOnTop(mainMenu);

engine.start();

}

For an implementation with sense, please have a look at the Demo.java class.
We will see the body of prepareStreams(Engine engine) in the next section.

The Streams

Now, we need to implement our custom input and output streams to be linked to our EditTexts etin and etout respectively.

Let’s see the content of prepareStreams():

private void prepareStreams(Engine engine) {

	final EditText outputText = findViewById(R.id.etout);
	final OutputStream out = new OutputStream(){
		@Override
		public void open() {}

		@Override
		public void close() {}

		@Override
		public void onOutput(final String s) {
			runOnUiThread(new Runnable() {
				@Override
				public void run() {
					outputText.append("\n"+ s);
				}
			});
		}
	};

	TextInputStream in = new TextInputStream(engine,
			(EditText) findViewById(R.id.etin),
			(Button) findViewById(R.id.btnok),
			out);

	engine.setInputStream(in);
	engine.setOutStream(out);
}

private void prepareStreams(Engine engine) {

final EditText outputText = findViewById(R.id.etout);

final OutputStream out = new OutputStream(){

@Override

public void open() {}

@Override

public void close() {}

@Override

public void onOutput(final String s) {

runOnUiThread(new Runnable() {

@Override

public void run() {

outputText.append("\n"+ s);

}

});

}

};

TextInputStream in = new TextInputStream(engine,

(EditText) findViewById(R.id.etin),

(Button) findViewById(R.id.btnok),

out);

engine.setInputStream(in);

engine.setOutStream(out);

}

As you can see, the implementation of the OutputStream is quite simple, since we will redirect the input string to the output EditText (in the UI thread, of course).

The TextInputStream needs some extra considerations:

public class TextInputStream extends InputStream {
    private final EditText et;
    private final Button btn;
    private final OutputStream outs;
    private String lastContent;

    public TextInputStream(Engine subscriber, EditText et, Button commit, OutputStream outs) {
        super(subscriber);
        this.et = et;
        this.btn = commit;
        this.outs = outs;

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                setLastContent(TextInputStream.this.et.getText().toString());
                TextInputStream.this.outs.onOutput(TextInputStream.this.et.getText().toString());
                TextInputStream.this.et.setText("");
            }
        });
    }

    @Override
    public String forceRead() {
        String ret = null;        
        //we can do this, since we're on another thread
        while(getLastContent()==null){
        }        
        ret = lastContent;
        setLastContent(null);
        return ret;
    }

    private synchronized String getLastContent() {
        return lastContent;
    }

    private synchronized void setLastContent(String lastContent) {
        this.lastContent = lastContent;
    }

    @Override
    public void close() {
        super.close();

    }
}

public class TextInputStream extends InputStream {

private final EditText et;

private final Button btn;

private final OutputStream outs;

private String lastContent;

public TextInputStream(Engine subscriber, EditText et, Button commit, OutputStream outs) {

super(subscriber);

this.et = et;

this.btn = commit;

this.outs = outs;

btn.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

setLastContent(TextInputStream.this.et.getText().toString());

TextInputStream.this.outs.onOutput(TextInputStream.this.et.getText().toString());

TextInputStream.this.et.setText("");

}

});

}

@Override

public String forceRead() {

String ret = null;

//we can do this, since we're on another thread

while(getLastContent()==null){

}

ret = lastContent;

setLastContent(null);

return ret;

}

private synchronized String getLastContent() {

return lastContent;

}

private synchronized void setLastContent(String lastContent) {

this.lastContent = lastContent;

}

@Override

public void close() {

super.close();

}

You can notice that the TextInputStream take the engine as the main subscriber and saves to lastContent the inputted text. The access to lastContent is managed by two synchronized methods (getLastContent() and setLastContent(…)). Finally, notice that the forceRead() method is called inside a dedicated Thread from the parent class InputStream, so it is safe to use that while loop inside.

Result

Let’s watch and enjoy our app (using the engine as in Demo.java) :

Category: java

Open Hugrade

CLIM on Android

The problem

The Layout

CLIM dependency

The Activity

The Streams

Result

CLIM