How to get value from a string in Android

Question

I started programming android application, but get stuck in a part where I need to get values from string. At this moment trying to make Calculator for Android. At this example I'm trying to get values just for add two values.

Adding my code:

MainActivity.java

public class MainActivity extends AppCompatActivity {

@Bind({R.id.button0, R.id.button1, R.id.button2, R.id.button3, R.id.button4, R.id.button5, R.id.button6, R.id.button7, R.id.button8,
        R.id.button9, R.id.buttonDot, R.id.buttonC, R.id.buttonDeleteLastSymbol, R.id.buttonMultiplication, R.id.buttonDivision, R.id.buttonSubtraction, R.id.buttonEqual})
List<Button> button;
@Bind(R.id.editText1)
EditText editText;

public String sign = "";
public Double mathDouble, mathDouble2;

static final ButterKnife.Action<View> DISABLE = new ButterKnife.Action<View>() {
    @Override
    public void apply(View view, int index) {
        view.setEnabled(false);
    }
};
static final ButterKnife.Setter<View, Boolean> ENABLED = new ButterKnife.Setter<View, Boolean>() {
    @Override
    public void set(View view, Boolean value, int index) {
        view.setEnabled(value);
    }
};

//Buttons 0-9
@OnClick({R.id.button0, R.id.button1, R.id.button2, R.id.button3, R.id.button4, R.id.button5, R.id.button6, R.id.button7, R.id.button8,
        R.id.button9, R.id.buttonDot})
void inputValue(Button button) {
    editText.append(button.getText());
}

@OnClick({R.id.buttonPlus, R.id.buttonSubtraction, R.id.buttonDivision, R.id.buttonMultiplication})
void inputSign(Button button) {
    sign = button.getText().toString();
    editText.append(sign);
}

public Double FirstValue() {
    String writtenText = editText.getText().toString();
    String firstValue = writtenText.substring(0, writtenText.indexOf("+"));

    return mathDouble = Double.parseDouble(firstValue);
}

Double SecondValue() {
    String writtenText = editText.getText().toString();
    String secondValue = writtenText.substring(writtenText.indexOf("+") + 1, writtenText.charAt(writtenText.length() - 1));
    return mathDouble2 = Double.parseDouble(secondValue);
}

//Buttons Equal, CE and C
@OnClick(R.id.buttonC)
void WriteLeftBracket() {
    editText.setText(String.valueOf(""));
}

@OnClick(R.id.buttonDeleteLastSymbol)
void WriteRightBracket() {
    if (editText.getText().toString().length() > 0) {
        editText.setText(editText.getText().toString().substring(0, editText.getText().toString().length() - 1));
        editText.setSelection(editText.getText().length());
    }
}

@OnClick(R.id.buttonEqual)
void Equal(Button button) {
    editText.append(button.getText());
    editText.setText(Double.toString(mathDouble + mathDouble2));
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    ButterKnife.bind(this);
}
}

content_main.xml

<RelativeLayout
    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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MainActivity"
    tools:showIn="@layout/activity_main">

    <LinearLayout
        android:id="@+id/layout1"
        android:layout_width="match_parent"
        android:layout_height="60dp">

        <EditText
            android:id="@+id/editText1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:singleLine="true"
            android:lines="1"
            />

    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/layout1">

        <Button
            android:id="@+id/buttonC"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:text="@string/erase"
            android:textSize="30sp" />

        <Button
            android:id="@+id/buttonDeleteLastSymbol"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:text="@string/delete"
            android:textStyle="bold"
            android:textSize="30sp" />

        <Button
            android:id="@+id/buttonMultiplication"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:text="@string/multiplication"
            android:textSize="30sp" />

    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/linearLayout1">

        <Button
            android:id="@+id/button7"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/seven"
            android:textSize="30sp" />

        <Button
            android:id="@+id/button8"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/eight"
            android:textSize="30sp" />

        <Button
            android:id="@+id/button9"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/nine"
            android:textSize="30sp" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/linearLayout2">

        <Button
            android:id="@+id/button4"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/four"
            android:textSize="30sp" />

        <Button
            android:id="@+id/button5"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/five"
            android:textSize="30sp" />

        <Button
            android:id="@+id/button6"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/six"
            android:textSize="30sp" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/linearLayout3">

        <Button
            android:id="@+id/button1"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/one"
            android:textSize="30sp" />

        <Button
            android:id="@+id/button2"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/two"
            android:textSize="30sp" />

        <Button
            android:id="@+id/button3"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/three"
            android:textSize="30sp" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/linearLayout4">

        <Button
            android:id="@+id/button0"
            android:layout_width="160dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/zero"
            android:textSize="30sp" />

        <Button
            android:id="@+id/buttonDot"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/dot"
            android:textSize="30sp" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/layout1"
        android:layout_toRightOf="@id/linearLayout1">

        <Button
            android:id="@+id/buttonDivision"
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layoutDirection="inherit"
            android:text="@string/division"
            android:textSize="30sp" />

    </LinearLayout>

    <Button
        android:id="@+id/buttonSubtraction"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_below="@+id/linearLayout1"
        android:layout_toEndOf="@+id/linearLayout1"
        android:text="@string/subtraction"
        android:textSize="30sp" />

    <Button
        android:id="@+id/buttonEqual"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_below="@+id/linearLayout2"
        android:layout_toEndOf="@+id/linearLayout1"
        android:text="@string/equal"
        android:textSize="30sp" />
    <Button
        android:id="@+id/buttonPlus"
        android:layout_width="80dp"
        android:layout_height="160dp"
        android:layout_below="@+id/linearLayout3"
        android:layout_toEndOf="@+id/linearLayout1"
        android:text="@string/plus"
        android:textSize="30sp"

        />

</RelativeLayout>

strings.xml

    <resources>
    <string name="app_name">Calculator</string>
    <string name="action_settings">Settings</string>
    <string name="dot">.</string>
    <string name="plus">+</string>
    <string name="subtraction">-</string>
    <string name="division">/</string>
    <string name="multiplication">*</string>
    <string name="equal">=</string>
    <string name="erase">C</string>
    <string name="delete">←</string>

    //Numbers
    <string name="one">1</string>
    <string name="two">2</string>
    <string name="three">3</string>
    <string name="four">4</string>
    <string name="five">5</string>
    <string name="six">6</string>
    <string name="seven">7</string>
    <string name="eight">8</string>
    <string name="nine">9</string>
    <string name="zero">0</string>
    <string name="illegal_argument_exeption">Cannot Divide By Zero!</string>
</resources>

Answer 1

Use this to get value:

getResources().getString("R.string.StringName");

For example

String zero = getResources().getString("R.string.zero");

Answer 2

你只需要使用

getResources().getString(R.string.stringName)