Android 安卓DataBinding（七）·事件绑定

分手后的思念是犯贱 2023-06-02 09:21 27阅读 0赞

### 文章目录 ###

*   *  前景回顾
     *  事件绑定
     *  整体思路
     *  拓展
     *  运行效果

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## 前景回顾 ##

[Android 安卓DataBinding（一）·基础][Android _DataBinding]  
[Android 安卓DataBinding（二）·入门][Android _DataBinding 1]  
[Android 安卓DataBinding（三）·单向绑定 BaseObservable][Android _DataBinding_ BaseObservable]  
[Android 安卓DataBinding（四）·单向绑定 ObservableField][Android _DataBinding_ ObservableField]  
[Android 安卓DataBinding（五）·单向绑定 ObservableCollection（集合使用）][Android _DataBinding_ ObservableCollection]  
[Android 安卓DataBinding（六）·双向绑定][Android _DataBinding 2]

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## 事件绑定 ##

在上面有些文章中已经有些事件绑定了，下面来看看事件绑定的具体用法。  
android:onClick  
android:afterTextChanged  
…

android:afterTextChanged 和 android:onTextChanged 可以用于EditText中

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## 整体思路 ##

以输入账号密码来进行模拟，模拟使用android:onClick、android:afterTextChanged 和 android:onTextChanged 。跟我一起来做！

修改Bean类：  
username 和 password 分别表示账号和密，用final来修饰，如果你不知道为什么我要用final修饰，请看我第四篇文章------[Android 安卓DataBinding（四）·单向绑定 ObservableField][Android _DataBinding_ ObservableField]

package com.lkdot.data;
    
    import android.databinding.ObservableField;
    
    public class DataBean { 
        public final ObservableField<String> username;
        public final ObservableField<String> password;
    
        public DataBean(ObservableField<String> username, ObservableField<String> password) { 
            this.username = username;
            this.password = password;
        }
    
        public ObservableField<String> getUsername() { 
            return username;
        }
    
        public ObservableField<String> getPassword() { 
            return password;
        }
    }

--------------------

MainActivity.java  
写出 Listener 内部类，不要忘记 activityMainBinding.setListener(new Listener()); 哦！！！

package com.lkdot.data;
    
    import android.annotation.SuppressLint;
    import android.databinding.DataBindingUtil;
    import android.databinding.ObservableField;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.text.Editable;
    import android.view.View;
    import android.widget.Toast;
    
    import com.lkdot.data.databinding.ActivityMainBinding;
    
    public class MainActivity extends AppCompatActivity { 
    
        private ActivityMainBinding activityMainBinding;
        private DataBean dataBean;
    
        @SuppressLint({ "SetTextI18n", "InlinedApi"})
        @Override
        protected void onCreate(Bundle savedInstanceState) { 
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            activityMainBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);
    
            //这句不用管，是关于安卓状态栏的
            getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);
    
            dataBean = new DataBean(new ObservableField<String>(), new ObservableField<String>());
    
            activityMainBinding.setData(dataBean);
    
            activityMainBinding.setListener(new Listener());
    
        }
    
        public class Listener { 
    
            public void onClick(DataBean dataBean) { 
                Toast.makeText(MainActivity.this, "UserName：" + dataBean.getUsername().get(), Toast.LENGTH_SHORT).show();
            }
    
            public void afterUserNameChanged(Editable editable) { 
                dataBean.getUsername().set(editable.toString());
            }
    
            public void afterPasswordChanged(Editable editable) { 
                dataBean.getPassword().set(editable.toString());
            }
    
        }
    }

--------------------

布局文件：  
注意记得有两个import哦！之后进行事件绑定！

<?xml version="1.0" encoding="utf-8"?>
    <layout 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">
    
        <data>
    
            <import type="com.lkdot.data.MainActivity.Listener" />
    
            <import type="com.lkdot.data.DataBean" />
    
            <variable name="listener" type="Listener" />
    
            <variable name="data" type="DataBean" />
    
        </data>
    
        <android.support.constraint.ConstraintLayout android:layout_width="match_parent" android:layout_height="match_parent" android:background="#FFFFFF" tools:context=".MainActivity">
    
            <TextView android:id="@+id/textView4" android:layout_width="match_parent" android:layout_height="30dp" android:layout_marginTop="8dp" android:gravity="left|center" android:paddingLeft="20dp" android:text="username:" app:layout_constraintTop_toTopOf="parent" tools:ignore="MissingConstraints" />
    
            <TextView android:id="@+id/textView5" android:layout_width="match_parent" android:layout_height="45dp" android:background="#03A9F4" android:gravity="left|center" android:onClick="@{() -> listener.onClick(data)}" android:paddingLeft="20dp" android:text="@{data.username}" android:textColor="#FFFFFF" android:textSize="14dp" android:textStyle="bold" app:layout_constraintTop_toBottomOf="@+id/textView4" tools:ignore="MissingConstraints" tools:layout_editor_absoluteX="0dp" />
    
            <TextView android:id="@+id/textView6" android:layout_width="match_parent" android:layout_height="30dp" android:layout_marginTop="15dp" android:gravity="center|left" android:paddingLeft="20dp" android:text="password:" app:layout_constraintTop_toBottomOf="@+id/textView5" tools:ignore="MissingConstraints" tools:layout_editor_absoluteX="0dp" />
    
            <TextView android:id="@+id/textView7" android:layout_width="match_parent" android:layout_height="45dp" android:background="#03A9F4" android:gravity="left|center" android:paddingLeft="20dp" android:text="@{data.password}" android:textColor="#FFFFFF" android:textSize="14dp" android:textStyle="bold" app:layout_constraintTop_toBottomOf="@+id/textView6" tools:ignore="MissingConstraints" tools:layout_editor_absoluteX="0dp" />
    
            <EditText android:id="@+id/editText" android:layout_width="match_parent" android:layout_height="40dp" android:layout_marginTop="25dp" android:afterTextChanged="@{listener.afterUserNameChanged}" android:background="#F2F2F2" android:hint="请输入UserName" android:paddingLeft="20dp" android:textSize="14dp" app:layout_constraintTop_toBottomOf="@+id/textView7" tools:ignore="MissingConstraints" tools:layout_editor_absoluteX="0dp" />
    
            <EditText android:layout_width="match_parent" android:layout_height="40dp" android:layout_marginTop="15dp" android:afterTextChanged="@{listener.afterPasswordChanged}" android:background="#F2F2F2" android:hint="请输入密码" android:paddingLeft="20dp" android:password="true" android:textSize="14dp" app:layout_constraintTop_toBottomOf="@+id/editText" tools:ignore="MissingConstraints" tools:layout_editor_absoluteX="0dp" />
            
        </android.support.constraint.ConstraintLayout>
    </layout>

--------------------

## 拓展 ##

上面呢，用的是事件监听绑定方法，还有一种方法引用，直接用 :: 即可，  
如： android:onClick="@\{listener::onClick\}" 就是方法引用绑定！

--------------------

## 运行效果 ##

输入密码黑屏了哈，手机自带的，保护密码用的，相信你能看懂  
![在这里插入图片描述][20191005010757783.gif]

[Android _DataBinding]: https://blog.csdn.net/qq_40881680/article/details/101714634
[Android _DataBinding 1]: https://blog.csdn.net/qq_40881680/article/details/101781705
[Android _DataBinding_ BaseObservable]: https://blog.csdn.net/qq_40881680/article/details/101800669
[Android _DataBinding_ ObservableField]: https://blog.csdn.net/qq_40881680/article/details/101847386
[Android _DataBinding_ ObservableCollection]: https://blog.csdn.net/qq_40881680/article/details/101993642
[Android _DataBinding 2]: https://blog.csdn.net/qq_40881680/article/details/102010622
[20191005010757783.gif]: /images/20230601/ef01e0f1456942769e6771bd15043319.png