Android 软键盘丝滑切换(一)

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在开发app中，软键盘弹出会有卡顿，闪一下的现象，会影响体验效果。为了实现微信软键盘与表情面板流畅的切换效果，查看了好多例子，查阅的很多资料，换了几种实现方式，都达不到流畅切换的效果，最终结合资料，参考网上的很多例子实现了想要的效果。（由于Demo中代码部分为Java代码，所以文中代码也由Kotlin与Java组成）Demo地址：https://github.com/xiaoyu00/KeyboardDemo

效果图

实现思路

在manifest android:windowSoftInputMode属性提供了系统自带的键盘弹出界面变化的几种方式，但都达不到流畅切换效果，更别说更复杂的微信键盘切换了，所以我们不用系统的方式，自己实现。
首先要实时获取到软键盘弹出时的属性：是否弹出，动画执行过程，高度等；然后在界面加载完成后计算带表情面板布局的高度；最后围绕键盘弹出收回的过程中，在键盘属性变化时对整个布局做平移处理。

实现

一、键盘监听

键盘的变化监听是整个实现的核心，Android手机的键盘所有属性是直接获取不到的。监听键盘变化只能用其它方式，网上有几种方方法，我这选择的是根view Insets监听方式（实现OnApplyWindowInsetsListener接口，设置ViewCompat.setWindowInsetsAnimationCallback）。

1.自定义RootViewDeferringInsetsCallback继承WindowInsetsAnimationCompat.Callback实现OnApplyWindowInsetsListener接口

public class RootViewDeferringInsetsCallback extends WindowInsetsAnimationCompat.Callback implements OnApplyWindowInsetsListener {

　　private View view;
　　private WindowInsetsCompat lastWindowInsets;
　　private boolean deferredInsets = false;
　　private int persistentInsetTypes;
　　private int deferredInsetTypes;
　　private boolean isPadding = false;

　　...//构造方法

　　@Override
　　public WindowInsetsCompat onApplyWindowInsets(View v, WindowInsetsCompat windowInsets) {
   　　 view = v;
   　　 lastWindowInsets = windowInsets;
   　　 if (isPadding) {
        　　int types;
       　　 if (deferredInsets) {
            　　types = deferredInsetTypes;
       　　 } else {
            　　types = persistentInsetTypes | deferredInsetTypes;
        　　}

        　　Insets typeInsets = windowInsets.getInsets(types);
        　　v.setPadding(typeInsets.left, typeInsets.top, typeInsets.right, typeInsets.bottom);
   　　 }

    　　return WindowInsetsCompat.CONSUMED;
　　}

　　@Override
　　public void onPrepare(@NonNull WindowInsetsAnimationCompat animation) {
    　　if ((animation.getTypeMask() & deferredInsetTypes) != 0) {
       　　 deferredInsets = true;
    　　}
　　}

　　@NonNull
　　@Override
　　public WindowInsetsCompat onProgress(@NonNull WindowInsetsCompat insets, @NonNull List<WindowInsetsAnimationCompat> runningAnimations) {
   　　 return insets;
　　}

　　@Override
　　public void onEnd(@NonNull WindowInsetsAnimationCompat animation) {
    　　if (deferredInsets && (animation.getTypeMask() & deferredInsetTypes) != 0) {
        　　deferredInsets = false;
       　　 if (lastWindowInsets != null && view != null) {
           　　 ViewCompat.dispatchApplyWindowInsets(view, lastWindowInsets);
       　　 }
   　　 }
　　}

2.定义KeyBoardListener接口

public interface KeyBoardListener {
    void onAnimStart(int moveDistance);
    void onAnimDoing(int offsetX,int offsetY);
    void onAnimEnd();
}

3.自定义KeyBoardInsetsCallBack继承RootViewDeferringInsetsCallback

public class KeyBoardInsetsCallBack extends RootViewDeferringInsetsCallback {
    public static final int KEYBOARD_TYPE = WindowInsetsCompat.Type.ime();
    public static final int SYSTEM_BAR_TYPE = WindowInsetsCompat.Type.systemBars();
    private KeyBoardListener keyboardListener;

    public KeyBoardInsetsCallBack(int dispatchMode, KeyBoardListener keyboardListener) {
        super(dispatchMode);
        this.keyboardListener = keyboardListener;
    }

    public KeyBoardInsetsCallBack(KeyBoardListener keyboardListener) {
        this(DISPATCH_MODE_STOP, keyboardListener);
    }

    @NonNull
    @Override
    public WindowInsetsAnimationCompat.BoundsCompat onStart(@NonNull WindowInsetsAnimationCompat animation, @NonNull WindowInsetsAnimationCompat.BoundsCompat bounds) {
        keyboardListener.onAnimStart(bounds.getUpperBound().bottom - bounds.getLowerBound().bottom);//计算键盘弹出高度
        return super.onStart(animation, bounds);
    }

    @NonNull
    @Override
    public WindowInsetsCompat onProgress(@NonNull WindowInsetsCompat insets, @NonNull List<WindowInsetsAnimationCompat> runningAnimations) {
        Insets typesInset = insets.getInsets(KEYBOARD_TYPE);
        Insets otherInset = insets.getInsets(SYSTEM_BAR_TYPE);

        Insets subtract = Insets.subtract(typesInset, otherInset);
        Insets diff = Insets.max(subtract, Insets.NONE);
        keyboardListener.onAnimDoing(diff.left - diff.right, diff.top - diff.bottom);
        return insets;
    }

    @Override
    public void onEnd(@NonNull WindowInsetsAnimationCompat animation) {
        keyboardListener.onAnimEnd();
    }
}

4.最后在Activity中界面加载完成后添加键盘监听

val keyBoardInsetsCallBack =KeyBoardInsetsCallBack(object :
                KeyBoardListener {
                override fun onAnimStart(moveDistance: Int) {
                    ...
                }

                override fun onAnimDoing(offsetX: Int, offsetY: Int) {
                   ...
                }

                override fun onAnimEnd() {
                   ...
                }
     })
 ViewCompat.setWindowInsetsAnimationCallback(window.decorView, keyBoardInsetsCallBack)

这样就完成了键盘弹出收回过程的监听。

二、计算并设置View大小

在界面加载完成后计算View高度，contentLayout为根Layout

contentLayout.viewTreeObserver
            .addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
                override fun onGlobalLayout() {
                    contentLayout.viewTreeObserver.removeOnGlobalLayoutListener(this)
                    calculationLayoutSize()
                    initKeyBoardListener()
                }
            })

private fun calculationLayoutSize() {
        val layoutParams = contentLayout.layoutParams as FrameLayout.LayoutParams
        val layoutParams2 = listLayout.layoutParams as LinearLayout.LayoutParams
        val cHeight: Int = contentLayout.height
        PANEL_HEIGHT=(cHeight*0.45).toInt()//PANEL_HEIGHT为表情面板高度
        layoutParams2.height = cHeight
        listLayout.layoutParams = layoutParams2//listlayout为表情面板上面内容layout
        layoutParams.height = cHeight + PANEL_HEIGHT
        contentLayout.layoutParams = layoutParams
    }

整个布局xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:id="@+id/layout_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <LinearLayout
        android:id="@+id/layout_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
　　　　　　//滑动列表
        <ScrollView
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:text="Hello World!">
　　　　　　　　...
        </ScrollView>
　　　　　// 输入框
        <LinearLayout
            android:id="@+id/layout_edit"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:paddingVertical="6dp"
            android:paddingHorizontal="16dp">

            <EditText
                android:id="@+id/et_input"
                android:layout_width="0dp"
                android:layout_height="36dp"
                android:layout_weight="1"
                android:background="@drawable/msg_editor_border" />

            <ImageView
                android:id="@+id/face_btn"
                android:layout_width="26.88dp"
                android:layout_height="26.88dp"
                android:layout_margin="5dp"
                android:scaleType="fitXY"
                android:src="@drawable/action_face_selector" />
        </LinearLayout>
    </LinearLayout>

    <LinearLayout
        android:id="@+id/view_panel"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/grey"
        android:gravity="center"
        android:orientation="vertical">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            android:text="这是表情面板" />
    </LinearLayout>

</LinearLayout>