homework1

app/.gitignore

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+/build

app/build.gradle

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+apply plugin: 'com.android.application'
+
+android {
+    compileSdkVersion 23
+    buildToolsVersion "23.0.2"
+
+    defaultConfig {
+        applicationId "com.example.maksim.calculator"
+        minSdkVersion 15
+        targetSdkVersion 23
+        versionCode 1
+        versionName "1.0"
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+}
+
+dependencies {
+    compile fileTree(dir: 'libs', include: ['*.jar'])
+    testCompile 'junit:junit:4.12'
+    compile 'com.android.support:appcompat-v7:23.2.1'
+}

app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# By default, the flags in this file are appended to flags specified
+# in C:\Users\Maksim\AppData\Local\Android\sdk/tools/proguard/proguard-android.txt
+# You can edit the include path and order by changing the proguardFiles
+# directive in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# Add any project specific keep options here:
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}

app/src/androidTest/java/com/example/maksim/calculator/ApplicationTest.java

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+package com.example.maksim.calculator;
+
+import android.app.Application;
+import android.test.ApplicationTestCase;
+
+/**
+ * <a href="http://d.android.com/tools/testing/testing_android.html">Testing Fundamentals</a>
+ */
+public class ApplicationTest extends ApplicationTestCase<Application> {
+    public ApplicationTest() {
+        super(Application.class);
+    }
+}

app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.maksim.calculator">
+
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.AppCompat.Light.NoActionBar">
+        <activity android:name=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

app/src/main/java/com/example/maksim/calculator/MainActivity.java

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+package com.example.maksim.calculator;
+
+import android.support.v7.app.AppCompatActivity;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.TextView;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+public class MainActivity extends AppCompatActivity {
+    enum State {
+        FIRST, OPERATION, SECOND, RESULT
+    }
+
+    private TextView text;
+    private State state;
+    private char operation;
+    private StringBuffer result;
+    private Double leftOperand, rightOperand;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        text = (TextView) findViewById(R.id.screen);
+        if (savedInstanceState == null) {
+            result = new StringBuffer("0");
+            leftOperand = new Double(0);
+            rightOperand = new Double(0);
+            state = State.FIRST;
+            operation = '\0';
+        } else {
+            result = new StringBuffer(savedInstanceState.getString("result"));
+            leftOperand = new Double(savedInstanceState.getDouble("leftOperand"));
+            rightOperand = new Double(savedInstanceState.getDouble("rightOperand"));
+            state = (State) savedInstanceState.getSerializable("state");
+            operation = savedInstanceState.getChar("operation");
+        }
+        text.setText(result.toString());
+    }
+
+    public void onDigitClick(View view) {
+        if (state == State.OPERATION) {
+            state = State.SECOND;
+            leftOperand = Double.parseDouble(result.toString());
+            result = new StringBuffer("0");
+        }
+        if (state == State.RESULT)
+            this.onClearClick(view);
+
+        String digit = ((TextView) view).getText().toString();
+
+        if (state == State.FIRST || state == State.SECOND) {
+            result.append(digit);
+            if (result.charAt(0) == '0' && result.charAt(1) != '.') {
+                result.deleteCharAt(0);
+            }
+        }
+        text.setText(result.toString());
+    }
+
+    public void onDotClick(View view) {
+        if (state == State.RESULT) {
+            result = new StringBuffer("0.");
+            state = State.FIRST;
+            text.setText(result.toString());
+            return;
+        }
+        if (state == State.OPERATION) {
+            state = State.SECOND;
+            leftOperand = Double.parseDouble(result.toString());
+            result = new StringBuffer("0.");
+            text.setText(result.toString());
+            return;
+        }
+        if (result.toString().contains("."))
+            return;
+        result.append('.');
+        text.setText(result.toString());
+    }
+
+    public void onClearClick(View view) {
+        state = State.FIRST;
+        leftOperand = 0.0;
+        rightOperand = 0.0;
+        result = new StringBuffer("0");
+        text.setText(result.toString());
+    }
+
+    public void onChangeSignClick(View view) {
+        if (state == State.OPERATION)
+            return;
+        if (Double.valueOf(result.toString()) == 0.0)
+            return;
+        if (result.charAt(0) != '-')
+            result.insert(0, '-');
+        else
+            result.deleteCharAt(0);
+        text.setText(result.toString());
+    }
+
+    public void onDeleteClick(View view) {
+        if (state == State.OPERATION) {
+            operation = '\0';
+            state = State.FIRST;
+        }
+        if (result.length() > 1) {
+            result.deleteCharAt(result.length() - 1);
+        } else {
+            result = new StringBuffer("0");
+        }
+        text.setText(result.toString());
+    }
+
+    public void onResultClick(View view) {
+        if (state == State.FIRST)
+            return;
+        if (state == State.SECOND || state == State.OPERATION) {
+            rightOperand = Double.parseDouble(result.toString());
+        }
+        switch (operation) {
+            case '\0':
+                break;
+            case '+':
+                leftOperand += rightOperand;
+                break;
+            case '–':
+                leftOperand -= rightOperand;
+                break;
+            case '×':
+                leftOperand *= rightOperand;
+                break;
+            case '÷':
+                leftOperand /= rightOperand;
+                break;
+            default:
+                break;
+        }
+        leftOperand = new BigDecimal(leftOperand).setScale(5, RoundingMode.UP).doubleValue();
+
+        result = new StringBuffer(leftOperand.toString());
+        state = State.RESULT;
+        text.setText(result.toString());
+    }
+
+    public void onOperationClick(View view) {
+        if (state == State.FIRST) {
+            leftOperand = Double.parseDouble(result.toString());
+        }
+        if (state == State.SECOND) {
+            onResultClick(view);
+        }
+        state = State.OPERATION;
+        operation = ((TextView) view).getText().toString().charAt(0);
+    }
+
+    @Override
+    protected void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+        outState.putString("result", result.toString());
+        outState.putChar("operation", operation);
+        outState.putSerializable("state", state);
+        outState.putDouble("leftOperand", leftOperand.doubleValue());
+        outState.putDouble("rightOperand", rightOperand.doubleValue());
+    }
+}