Android 完美判断软键盘高度的方法

首先自定义一个ViewGroup，可以继承已有的LinearLayout等

public class KeyboardLayout extends LinearLayout {
public KeyboardLayout(Context context) {
    super(context);
}

public KeyboardLayout(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
}

public KeyboardLayout(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}

public KeyboardLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);

}

private int mLayoutHeight = 0;
private int mKeyboardHeight=0；


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int h = resolveSize(0, heightMeasureSpec);
    mLayoutHeight = Math.max(mLayoutHeight, h);  //这里记录原始布局
    mKeyboardHeight=Math.max(mKeyboardHeight,Math.abs(mLayoutHeight -h));
    if(mKeyboardHeight>mLayoutHeight/5){
        存储这个软键盘高度
    }
    
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

}

在login页面定义大致如下

核心是KeyboardLayout里面必须有一个ScrollView布局

  <LinearLayout>
      <KeyboardLayout>
              <ScrollView>
                      <EditText/>
                 </ScrollView>
      </KeyboardLayout>
 </LinearLayout>

下面是我的实际代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/default_content_background"
    android:orientation="vertical"
    tools:context=".modules.login.views.LoginActivity">

    <com.maple.subway.modules.login.views.layouts.KeyboardLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="20dp"
            android:background="@color/default_font_color" />

        <ScrollView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="vertical"
                android:padding="30dp">

                <com.maple.subway.commons.android.views.widgets.XTextView
                    android:layout_width="match_parent"
                    android:layout_height="60dp"
                    android:layout_marginTop="40dp"
                    android:text="@string/login_title"
                    android:textColor="@color/default_font_color"
                    android:textSize="28sp" />

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="25dp"
                    android:orientation="horizontal"
                    android:padding="5dp">

                    <com.maple.subway.commons.android.views.widgets.XTextView
                        android:layout_width="100dp"
                        android:layout_height="40dp"
                        android:text="@string/login_label_mobile"
                        android:textColor="@color/default_font_color"
                        android:textSize="20sp" />

                    <com.maple.subway.modules.login.views.ClearEditText
                        android:layout_width="match_parent"
                        android:layout_height="40dp"
                        android:layout_marginRight="30dp"

                        android:background="@null"
                        android:hint="@string/login_hint_mobile"
                        android:maxLines="1"
                        android:textColor="@color/login_edittext_color"
                        android:textColorHint="@color/login_edittext_hint_color"
                        android:textSize="20sp" />
                </LinearLayout>

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="1dp"
                    android:layout_marginTop="5dp"
                    android:background="@color/default_color"></LinearLayout>

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="15dp"
                    android:orientation="horizontal"
                    android:padding="5dp"
                    android:visibility="gone">

                    <com.maple.subway.commons.android.views.widgets.XTextView
                        android:layout_width="100dp"
                        android:layout_height="40dp"
                        android:text="@string/login_label_password"
                        android:textColor="@color/default_font_color"
                        android:textSize="20sp" />

                    <com.maple.subway.commons.android.views.widgets.XEditText
                        android:layout_width="match_parent"
                        android:layout_height="40dp"
                        android:layout_marginRight="30dp"

                        android:background="@null"
                        android:hint="@string/login_hint_password"
                        android:inputType="text"
                        android:maxLines="1"
                        android:textColor="@color/login_edittext_color"
                        android:textColorHint="@color/login_edittext_hint_color"
                        android:textSize="20sp" />
                </LinearLayout>

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="15dp"
                    android:orientation="horizontal"
                    android:padding="5dp">

                    <com.maple.subway.commons.android.views.widgets.XTextView
                        android:layout_width="100dp"
                        android:layout_height="40dp"
                        android:text="@string/login_label_message"
                        android:textColor="@color/default_font_color"
                        android:textSize="20sp" />

                    <com.maple.subway.modules.login.views.ClearEditText
                        android:layout_width="wrap_content"
                        android:layout_height="40dp"
                        android:layout_weight="1"

                        android:background="@null"
                        android:hint="@string/login_hint_message"
                        android:inputType="text"
                        android:maxLines="1"
                        android:textColor="@color/login_edittext_color"
                        android:textColorHint="@color/login_edittext_hint_color"
                        android:textSize="20sp" />

                    <com.maple.subway.commons.android.views.widgets.XButton
                        style="?android:attr/borderlessButtonStyle"
                        android:layout_width="110dp"
                        android:layout_height="32dp"
                        android:layout_marginBottom="2dp"
                        android:layout_marginLeft="10dp"
                        android:background="@drawable/login_button_background_message"
                        android:text="@string/login_send_message"
                        android:textColor="@color/default_font_color"
                        android:textSize="16sp" />
                </LinearLayout>

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="1dp"
                    android:layout_marginTop="5dp"
                    android:background="@color/default_color"></LinearLayout>

                <com.maple.subway.commons.android.views.widgets.XTextView
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="25dp"
                    android:padding="3dp"
                    android:text="@string/login_use_message"
                    android:textColor="@color/login_text_link_color"
                    android:textSize="20sp" />

                <com.maple.subway.commons.android.views.widgets.XButton
                    android:id="@+id/login_button_submit"
                    style="?android:attr/borderlessButtonStyle"
                    android:layout_width="match_parent"
                    android:layout_height="50dp"
                    android:layout_marginTop="35dp"
                    android:background="@drawable/login_button_background_submit"
                    android:text="@string/login_button_submit"
                    android:textAlignment="center"
                    android:textColor="@android:color/white"
                    android:textSize="20sp" />

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"></LinearLayout>

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="30dp"
                    android:gravity="center"
                    android:orientation="horizontal">

                    <com.maple.subway.commons.android.views.widgets.XTextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"

                        android:text="@string/login_find_password"
                        android:textColor="@color/login_text_link_color"
                        android:textSize="16sp" />

                    <LinearLayout
                        android:layout_width="1dp"
                        android:layout_height="match_parent"
                        android:layout_marginLeft="15dp"
                        android:layout_marginRight="15dp"
                        android:background="@color/login_edittext_hint_color"></LinearLayout>

                    <com.maple.subway.commons.android.views.widgets.XEditText
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"

                        android:text="@string/login_lock_account"
                        android:textColor="@color/login_text_link_color"
                        android:textSize="16sp" />
                </LinearLayout>
            </LinearLayout>
        </ScrollView>

        <com.maple.subway.commons.android.views.widgets.XEditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"

            android:text="@string/login_lock_account"
            android:textColor="@color/login_text_link_color"
            android:textSize="16sp" />
    </com.maple.subway.modules.login.views.layouts.KeyboardLayout>

</LinearLayout>

这样当软键盘出现以后，就会触发KeyboardLayout的onMeasure方法，两次高度计算出来的就是软键盘的高度。这个可以忽略机型和品牌的影响。

同时，也就是APP在启动时，必须引导用户触摸出现一次软键盘，不然就只能用我另外一个方法Android 获取底部导航栏高度。