java - Android 中如何从字符串中获取值

Question

我开始编写 Android 应用程序，但陷入了需要从字符串获取值的部分。目前正在尝试制作 Android 版计算器。在此示例中，我尝试获取仅用于添加两个值的值。

添加我的代码:

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

用它来获取值(value):

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

例如

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