鸿蒙开发（3）---TextField组件_鸿蒙 import textfield from

鸿蒙App开发之TextField

在前面的Text与Button讲解之后，我们实现了一个拨号的界面。但其实拨号的号码显示并不是使用Text组件，因为它监测删除太麻烦。

而真正用于拨号界面的组件是TextField文本框。同时，它也是继承自Text组件：

public class TextField extends Text
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和前面的章节一样，今天我们专门讲解TextField文本框的使用方式。

创建TextField

首先，我们还是使用XML布局文件进行TextField组件的创建。示例代码如下：

<TextField
    ohos:height="40vp"
    ohos:width="match_parent"
    ohos:text_size="25vp"
    ohos:margin="20vp"
    ohos:padding="5vp"
    ohos:background_element="$graphic:background_ability_main"
    ohos:hint="请输入用户名"
    ohos:basement="#00FF00"
    ohos:text_alignment="vertical_center"
/>
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运行之后，效果如下：

这里，有几个重要的数据我们需要注意，具体如下表所示：

我们在上面的代码中，并没有设置这个属性。下面，我们来将它改为矩形红色，示例代码如下：

ohos:element_cursor_bubble="$graphic:textfield_bubble"
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这里，我们只需要添加一行属性即可，graphic文件夹下textfield_bubble内容如下所示：

<?xml version="1.0" encoding="UTF-8" ?>
<shape
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:shape="rectangle">
    <solid
        ohos:color="#FF0000"/>
</shape>
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运行之后，效果如下：

实战登录界面

到今天，我们已经学习了3个组件：Text、Button以及TextField。

通过这3个组件，我们完全可以实现手机上的登录界面。下面，我们就来实现登录界面的效果。

首先，是我们XML的布局文件，代码如下：

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:alignment="center"
    ohos:background_element="$media:background"
    ohos:orientation="vertical">

    <Text
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:text_size="50vp"
        ohos:bottom_margin="20vp"
        ohos:text="登录界面"/>

    <StackLayout
        ohos:height="match_content"
        ohos:width="match_parent"
        ohos:margin="10vp">

        <TextField
            ohos:id="$+id:textfield_username"
            ohos:height="40vp"
            ohos:width="match_parent"
            ohos:text_size="25vp"
            ohos:background_element="$graphic:background_ability_main"
            ohos:text_alignment="vertical_center"
            ohos:padding="5vp"
            ohos:hint="请输入用户名"
            ohos:margin="10vp"/>

        <Text
            ohos:id="$+id:text_username"
            ohos:height="match_content"
            ohos:width="match_content"
            ohos:layout_alignment="right"
            ohos:text="输入的用户名错误"
            ohos:visibility="hide"
            ohos:text_size="15vp"
            ohos:text_color="#FF0000"
            ohos:margin="20vp"
            ohos:text_alignment="vertical_center"/>
    </StackLayout>

    <StackLayout
        ohos:height="match_content"
        ohos:width="match_parent"
        ohos:margin="10vp">

        <TextField
            ohos:id="$+id:textfield_password"
            ohos:height="40vp"
            ohos:width="match_parent"
            ohos:text_size="25vp"
            ohos:background_element="$graphic:background_ability_main"
            ohos:text_alignment="vertical_center"
            ohos:text_input_type="pattern_password"
            ohos:padding="5vp"
            ohos:hint="请输入密码"
            ohos:margin="10vp"/>

        <Text
            ohos:id="$+id:text_password"
            ohos:height="match_content"
            ohos:width="match_content"
            ohos:layout_alignment="right"
            ohos:text_size="15vp"
            ohos:text_color="#FF0000"
            ohos:text="密码输入错误"
            ohos:margin="20vp"
            ohos:visibility="hide"
            ohos:text_alignment="vertical_center"/>
    </StackLayout>

    <Button
        ohos:id="$+id:button_login"
        ohos:height="match_content"
        ohos:width="100vp"
        ohos:top_padding="5vp"
        ohos:bottom_padding="5vp"
        ohos:text_size="25vp"
        ohos:background_element="$graphic:background_ability_main"
        ohos:text="登录"/>
</DirectionalLayout>
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Java页面代码：

package com.liyuanjing.idacommunity.slice;

import com.liyuanjing.idacommunity.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Button;
import ohos.agp.components.Component;
import ohos.agp.components.Text;
import ohos.agp.components.TextField;
import ohos.agp.components.element.ShapeElement;

public class MainAbilitySlice extends AbilitySlice{
    private TextField username_textField;
    private TextField password_textField;
    private Button login_button;
    private Text username_text;
    private Text password_text;
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);
        //设置输入框不被软键盘遮挡
   		getWindow().setInputPanelDisplayType(WindowManager.LayoutConfig.INPUT_ADJUST_PAN);
        this.username_textField=(TextField)findComponentById(ResourceTable.Id_textfield_username);
        this.password_textField=(TextField)findComponentById(ResourceTable.Id_textfield_password);
        this.login_button=(Button) findComponentById(ResourceTable.Id_button_login);
        this.username_text=(Text)findComponentById(ResourceTable.Id_text_username);
        this.password_text=(Text)findComponentById(ResourceTable.Id_text_password);
        this.login_button.setClickedListener(new Component.ClickedListener() {
            @Override
            public void onClick(Component component) {
                username_text.setVisibility(Component.VISIBLE);
                password_text.setVisibility(Component.VISIBLE);
                //改变TextField错误样式
                ShapeElement errorElement = new ShapeElement(MainAbilitySlice.this, ResourceTable.Graphic_textfield_error);
                username_textField.setBackground(errorElement);
                password_textField.setBackground(errorElement);
            }
        });
        this.username_textField.setFocusChangedListener(new Component.FocusChangedListener() {
            @Override
            public void onFocusChange(Component component, boolean b) {
                if (b) {
                    // 获取到焦点
                    if(username_text.getVisibility()==Component.VISIBLE){
                        username_text.setVisibility(Component.INVISIBLE);
                    }
                } else {
                    //失去焦点
                    ShapeElement backgroundElement = new ShapeElement(MainAbilitySlice.this, ResourceTable.Graphic_background_ability_main);
                    username_textField.setBackground(backgroundElement);
                }
            }
        });
        this.password_textField.setFocusChangedListener(new Component.FocusChangedListener() {
            @Override
            public void onFocusChange(Component component, boolean b) {
                if (b) {
                    // 获取到焦点
                    if(password_text.getVisibility()==Component.VISIBLE){
                        password_text.setVisibility(Component.INVISIBLE);
                    }
                } else {
                    // 失去焦点
                    ShapeElement backgroundElement = new ShapeElement(MainAbilitySlice.this, ResourceTable.Graphic_background_ability_main);
                    password_textField.setBackground(backgroundElement);
                }
            }
        });
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}
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默认TextField样式（background_ability_main.xml）：

<?xml version="1.0" encoding="UTF-8" ?>
<shape
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:shape="rectangle">
    <corners
    ohos:radius="50"/>
    <stroke
        ohos:width="5"
        ohos:color="#00FF00"/>
    <solid
        ohos:color="#FFFFFFFF"/>
</shape>
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点击登录后TextField样式（textfield_error.xml）：

<?xml version="1.0" encoding="UTF-8" ?>
<shape
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:shape="rectangle">
    <corners
        ohos:radius="50"/>
    <stroke
        ohos:width="5"
        ohos:color="#FF0000"/>
    <solid
        ohos:color="#FFFFFFFF"/>
</shape>
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这里需要注意的是，通过Java改变TextField的代码为：

ShapeElement backgroundElement = new ShapeElement(MainAbilitySlice.this, ResourceTable.Graphic_background_ability_main);
username_textField.setBackground(backgroundElement);
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同样的，TextField获取焦点事件以及失去焦点事件由FocusChangedListener进行实现，代码如下：

this.password_textField.setFocusChangedListener(new Component.FocusChangedListener() {
            @Override
    public void onFocusChange(Component component, boolean b) {
        if (b) {
            // 获取到焦点
        } else {
            // 失去焦点
        }
    }
});
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最终实现的效果如首图所示。