Korrektes zuweisen der FractionCalculator zur DataBinding-Funktionalität

app/src/main/java/io/n0x/android/java_mot_testing/FractionCalculator.java

@@ -5,55 +5,82 @@ import android.util.Log;
 import android.widget.TextView;
 
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.databinding.BaseObservable;
+import androidx.databinding.Bindable;
 
-public class FractionCalculator{
+public class FractionCalculator extends BaseObservable{
 
     private static final String TAG = FractionCalculator.class.getName();
 
-    private int enumLeft;
-    private int denomLeft;
-    private int enumRight;
-    private int denomRight;
-    public int enumResult;
-    public int denomResult;
+    private String denomLeft;
+    private String enumLeft;
+    private String denomRight;
+    private String enumRight;
+    private String denomResult;
+    private String enumResult;
 
-
-    protected void doStuff() {
-          Log.d(TAG, "FractionCalculator started");
+    public FractionCalculator(){
+        Log.d(TAG, "new FractionCalculator created");
     }
 
-    public int getEnumLeft() {
-        return enumLeft;
-    }
-
-    public void setEnumLeft(int enumLeft) {
-        this.enumLeft = enumLeft;
-    }
-
-    public int getDenomLeft() {
+    /// #### GETTER AND SETTER ####
+    @Bindable
+    public String getDenomLeft() {
         return denomLeft;
     }
 
-    public void setDenomLeft(int denomLeft) {
+    public void setDenomLeft(String denomLeft) {
         this.denomLeft = denomLeft;
+        notifyPropertyChanged(BR.denomLeft);
     }
 
-    public int getEnumRight() {
-        return enumRight;
+    @Bindable
+    public String getEnumLeft() {
+        return enumLeft;
     }
 
-    public void setEnumRight(int enumRight) {
-        this.enumRight = enumRight;
+    public void setEnumLeft(String enumLeft) {
+        this.enumLeft = enumLeft;
+        notifyPropertyChanged(BR.enumLeft);
     }
 
-    public int getDenomRight() {
+    @Bindable
+    public String getDenomRight() {
         return denomRight;
     }
 
-    public void setDenomRight(int denomRight) {
+    public void setDenomRight(String denomRight) {
         this.denomRight = denomRight;
+        notifyPropertyChanged(BR.denomRight);
     }
 
-    // GETTER AND SETTER
+    @Bindable
+    public String getEnumRight() {
+        return enumRight;
+    }
 
+    public void setEnumRight(String enumRight) {
+        this.enumRight = enumRight;
+        notifyPropertyChanged(BR.enumRight);
+    }
+
+    @Bindable
+    public String getDenomResult() {
+        return denomResult;
+    }
+
+    public void setDenomResult(String denomResult) {
+        this.denomResult = denomResult;
+        notifyPropertyChanged(BR.denomResult);
+    }
+
+    @Bindable
+    public String getEnumResult() {
+        return enumResult;
+    }
+
+    public void setEnumResult(String enumResult) {
+        this.enumResult = enumResult;
+        notifyPropertyChanged(BR.enumResult);
+    }
 }

app/src/main/java/io/n0x/android/java_mot_testing/MainActivity.java

@@ -1,54 +1,52 @@
 package io.n0x.android.java_mot_testing;
 
-import android.content.Intent;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.widget.TextView;
 
 import androidx.appcompat.app.AppCompatActivity;
-import androidx.databinding.BindingAdapter;
+import androidx.databinding.DataBindingUtil;
+
+import io.n0x.android.java_mot_testing.databinding.Ex9DataBindingBinding;
 
 public class MainActivity extends AppCompatActivity implements View.OnClickListener {
-
+    // For debugging
     private static final String TAG = MainActivity.class.getName();
-
-
-
-    FractionCalculator calc = new FractionCalculator();
+    // Local calculator instance
+    private FractionCalculator calc;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        setContentView(R.layout.ex9_data_binding);
-        Log.d(TAG, "MainActivity started");
+        // create calculator instance
+        calc = new FractionCalculator();
 
+        // set a value for testing
+        calc.setEnumResult("0");
+        calc.setDenomResult("0");
 
-         // Button Listeners
+        // Bind instance of FractionCalculator to view
+        Ex9DataBindingBinding binding = DataBindingUtil.setContentView(this, R.layout.ex9_data_binding);
+        binding.setCalc(calc);
+
+        // Button Listeners
         findViewById(R.id.button_add).setOnClickListener(this);
 
-        calc.doStuff();
+        // Log create action
+        Log.d(TAG, "MainActivity started");
     }
 
     @Override
     public void onClick(View v) {
         if (v.getId() == R.id.button_add) {
 
+            // works (without using bindings)
             TextView textView = findViewById(R.id.txt_enum_result);
-            textView.setText("10");
+            textView.setText("1234");
 
-            calc.enumResult = 5;
-            calc.denomResult = 6;
-
-            //calc.setDenomLeft(10);
-/*
-            enumLeft = 1;
-            denomLeft = 2;
-            enumRight = 3;
-            denomRight = 4;
-
-
- //*/
+            // work with DataBinding
+            calc.setDenomLeft("123123123");
         }
     }
 }

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

@@ -1,18 +0,0 @@
-<?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">
-
-    <TextView
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="Hello World!"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintLeft_toLeftOf="parent"
-        app:layout_constraintRight_toRightOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
-
-</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/ex9_data_binding.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<layout xmlns:tools="http://schemas.android.com/tools"
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     xmlns:app="http://schemas.android.com/apk/res-auto">
 
     <data>
@@ -8,7 +9,7 @@
             type="io.n0x.android.java_mot_testing.FractionCalculator" />
     </data>
 
-    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    <androidx.constraintlayout.widget.ConstraintLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent">
 
@@ -53,43 +54,41 @@
             android:id="@+id/txt_equals"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:layout_marginTop="48dp"
+            android:layout_marginTop="60dp"
             android:text="="
             android:textSize="34sp"
             app:layout_constraintEnd_toEndOf="parent"
-            app:layout_constraintHorizontal_bias="0.183"
+            app:layout_constraintHorizontal_bias="0.181"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/button_div" />
+
+        <TextView
+            android:id="@+id/txt_enum_result"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="64dp"
+            android:text="@{calc.enumResult}"
+            android:textAlignment="center"
+            android:textSize="34sp"
+            app:layout_constraintBottom_toTopOf="@+id/txt_denom_result"
+            app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@+id/button_div" />
 
         <TextView
-            android:text="@{calc.denomResult}"
             android:id="@+id/txt_denom_result"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginTop="3dp"
             android:layout_marginBottom="412dp"
+            android:text="@{calc.denomResult}"
             android:textAlignment="center"
             android:textSize="34sp"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
-            app:layout_constraintHorizontal_bias="0.247"
-            app:layout_constraintStart_toEndOf="@+id/txt_equals"
+            app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@+id/txt_enum_result" />
 
-        <TextView
-            android:text="Test1234"
-            android:id="@+id/txt_enum_result"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_marginTop="32dp"
-            android:textAlignment="center"
-            android:textSize="34sp"
-            app:layout_constraintBottom_toTopOf="@+id/txt_denom_result"
-            app:layout_constraintEnd_toEndOf="parent"
-            app:layout_constraintHorizontal_bias="0.247"
-            app:layout_constraintStart_toEndOf="@+id/txt_equals"
-            app:layout_constraintTop_toBottomOf="@+id/button_div" />
-
         <EditText
             android:text="@{calc.enumRight}"
             android:id="@+id/enumRight"
@@ -104,7 +103,7 @@
             app:layout_constraintTop_toTopOf="parent" />
 
         <EditText
-            android:text="@{calc.enumLeft}"
+            android:text="@{calc.enumRight}"
             android:id="@+id/enumLeft"
             android:layout_width="140dp"
             android:layout_height="50dp"