Button

Button是一种常见的组件，点击可以触发对应的操作，通常由文本或图标组成，也可以由图标和文本共同组成。

图1 文本按钮 img

图2 图标按钮 img

图3 图标和文本共同组成的按钮 img

支持的XML属性

Button无自有的XML属性，共有XML属性继承自Text

创建Button

创建如下样式的按钮：

img

  1. 在layout目录下的xml文件中创建Button，并设置按钮的背景形状、颜色。

    常用的背景如文本背景、按钮背景，通常采用XML格式放置在graphic目录下。

    <Button    ohos:id="$+id:button"    ohos:width="match_content"    ohos:height="match_content"    ohos:text_size="27fp"    ohos:text="button"    ohos:background_element="$graphic:background_button"       ohos:left_margin="15vp"    ohos:bottom_margin="15vp"    ohos:right_padding="8vp"    ohos:left_padding="8vp"    ohos:element_left="$media:ic_btn_reload"/>

  2. 在“Project”窗口，打开“entry > src > main > resources > base”，右键点击“graphic”文件夹，选择“New > File”，命名为“background_button.xml”，在该文件中定义按钮的背景形状、颜色。

    <?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="rectangle">    <corners        ohos:radius="10"/>    <solid        ohos:color="#007CFD"/></shape>

响应点击事件

按钮的重要作用是当用户单击按钮时，会执行相应的操作或者界面出现相应的变化。实际上用户点击按钮时，Button对象将收到一个点击事件。开发者可以自定义响应点击事件的方法。例如，通过创建一个Component.ClickedListener对象，然后通过调用setClickedListener将其分配给按钮。

Button button = (Button) findComponentById(ResourceTable.Id_button);// 为按钮设置点击事件回调button.setClickedListener(new Component.ClickedListener() {    @Override    public void onClick(Component component) {        // 此处添加点击按钮后的事件处理逻辑    }});

不同类型的按钮

按照按钮的形状，按钮可以分为：普通按钮，椭圆按钮，胶囊按钮，圆形按钮等。

  • 普通按钮

    img

    普通按钮和其他按钮的区别在于不需要设置任何形状，只设置文本和背景颜色即可，例如：

    <Button    ohos:width="150vp"    ohos:height="50vp"    ohos:text_size="27fp"    ohos:text="button"    ohos:background_element="$graphic:color_blue_element"    ohos:left_margin="15vp"    ohos:bottom_margin="15vp"    ohos:right_padding="8vp"    ohos:left_padding="8vp"/>

    color_blue_element.xml：

    <?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="rectangle">    <solid        ohos:color="#007CFD"/></shape>

  • 椭圆按钮

    img

    椭圆按钮是通过设置background_element的来实现的，background_element的shape设置为椭圆（oval），例如：

    <Button    ohos:width="150vp"    ohos:height="50vp"    ohos:text_size="27fp"    ohos:text="button"    ohos:background_element="$graphic:oval_button_element"    ohos:left_margin="15vp"    ohos:bottom_margin="15vp"    ohos:right_padding="8vp"    ohos:left_padding="8vp"    ohos:element_left="$media:ic_btn_reload"/>

    oval_button_element.xml:

    <?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="oval">    <solid        ohos:color="#007CFD"/></shape>

  • 胶囊按钮

    img

    胶囊按钮是一种常见的按钮，设置按钮背景时将背景设置为矩形形状，并且设置ShapeElement的radius的半径，例如：

    <Button    ohos:id="$+id:button"    ohos:width="match_content"    ohos:height="match_content"    ohos:text_size="27fp"    ohos:text="button"    ohos:background_element="$graphic:capsule_button_element"    ohos:left_margin="15vp"    ohos:bottom_margin="15vp"    ohos:right_padding="15vp"    ohos:left_padding="15vp"/>

    capsule_button_element.xml:

    <?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="rectangle">    <corners        ohos:radius="100"/>    <solid        ohos:color="#007CFD"/></shape>

  • 圆形按钮

    img

    圆形按钮和椭圆按钮的区别在于组件本身的宽度和高度需要相同，例如：

    <Button    ohos:id="$+id:button"    ohos:width="50vp"    ohos:height="50vp"    ohos:text_size="27fp"    ohos:background_element="$graphic:circle_button_element"    ohos:text="+"    ohos:left_margin="15vp"    ohos:bottom_margin="15vp"    ohos:right_padding="15vp"    ohos:left_padding="15vp"/>

    circle_button_element.xml:

    <?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="oval">    <solid        ohos:color="#007CFD"/></shape>

场景示例

利用圆形按钮，胶囊按钮，文本组件可以绘制出如下拨号盘的UI界面。

图4 界面效果

img

源码示例：

<?xml version="1.0" encoding="utf-8"?><DirectionalLayout    xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:width="match_parent"    ohos:height="match_parent"    ohos:background_element="$graphic:color_light_gray_element"    ohos:orientation="vertical">    <Text        ohos:width="match_content"        ohos:height="match_content"        ohos:text_size="20fp"        ohos:text="0123456789"        ohos:background_element="$graphic:green_text_element"        ohos:text_alignment="center"        ohos:layout_alignment="horizontal_center"    />    <DirectionalLayout        ohos:width="match_parent"        ohos:height="match_content"        ohos:alignment="horizontal_center"        ohos:orientation="horizontal"        ohos:top_margin="5vp"        ohos:bottom_margin="5vp">        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="1"            ohos:text_alignment="center"        />        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="2"            ohos:left_margin="5vp"            ohos:right_margin="5vp"            ohos:text_alignment="center"        />        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="3"            ohos:text_alignment="center"        />    </DirectionalLayout>    <DirectionalLayout        ohos:width="match_parent"        ohos:height="match_content"        ohos:alignment="horizontal_center"        ohos:orientation="horizontal"        ohos:bottom_margin="5vp">        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="4"            ohos:text_alignment="center"        />        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:left_margin="5vp"            ohos:right_margin="5vp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="5"            ohos:text_alignment="center"        />        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="6"            ohos:text_alignment="center"        />    </DirectionalLayout>    <DirectionalLayout        ohos:width="match_parent"        ohos:height="match_content"        ohos:alignment="horizontal_center"        ohos:orientation="horizontal"        ohos:bottom_margin="5vp">        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="7"            ohos:text_alignment="center"        />        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:left_margin="5vp"            ohos:right_margin="5vp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="8"            ohos:text_alignment="center"        />        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="9"            ohos:text_alignment="center"        />    </DirectionalLayout>    <DirectionalLayout        ohos:width="match_parent"        ohos:height="match_content"        ohos:alignment="horizontal_center"        ohos:orientation="horizontal"        ohos:bottom_margin="5vp">        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="*"            ohos:text_alignment="center"        />        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:left_margin="5vp"            ohos:right_margin="5vp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="0"            ohos:text_alignment="center"        />        <Button            ohos:width="40vp"            ohos:height="40vp"            ohos:text_size="15fp"            ohos:background_element="$graphic:green_circle_button_element"            ohos:text="#"            ohos:text_alignment="center"        />    </DirectionalLayout>    <Button        ohos:width="match_content"        ohos:height="match_content"        ohos:text_size="15fp"        ohos:text="CALL"        ohos:background_element="$graphic:green_capsule_button_element"        ohos:bottom_margin="5vp"        ohos:text_alignment="center"        ohos:layout_alignment="horizontal_center"        ohos:left_padding="10vp"        ohos:right_padding="10vp"        ohos:top_padding="2vp"        ohos:bottom_padding="2vp"    /></DirectionalLayout>

color_light_gray_element.xml：

<?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="rectangle">    <solid        ohos:color="#EDEDED"/></shape>

green_text_element.xml：

<?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="rectangle">    <corners        ohos:radius="20"/>    <stroke        ohos:width="2"        ohos:color="#006E00"/>    <solid        ohos:color="#EDEDED"/></shape>

green_circle_button_element.xml：

<?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="oval">    <stroke        ohos:width="5"        ohos:color="#006E00"/>    <solid        ohos:color="#EDEDED"/></shape>

green_capsule_button_element.xml：

<?xml version="1.0" encoding="utf-8"?><shape xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:shape="rectangle">    <corners        ohos:radius="100"/>    <solid        ohos:color="#006E00"/></shape>

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