Android監聽輸入法並獲取高度——輸入法與頁面佈局無縫切換

時間 2019-11-21

標籤 android 監聽輸入法獲取高度頁面佈局無縫切換欄目 Android 简体版

原文原文鏈接

在QQ或者微信的聊天頁面，當輸入法和表情欄互相切換時，過分很是天然，並且表情欄高度恰好跟輸入法同樣。我的感受這種用戶體驗特別的好，別看這個細節小，但代碼實現處理起來仍是有必定難度。今天就帶你們來實現這種效果，下面是效果圖：php

監聽輸入法的彈起和隱藏

首先，咱們須要知道輸入法的高度，使表情欄的高度與之保持一致。可是Android是沒有提供現成的接口給開發者監聽輸入法的狀態，所以須要自定義的KeyboardLayout，監聽佈局的改變。視圖樹ViewTreeObserver發生變化時會回調OnGlobalLayoutListener.onGlobalLayout()方法，經過變化先後佈局高度差計算出輸入法的高度。java

public class KeyboardLayout extends FrameLayout {

    private KeyboardLayoutListener mListener;
    private boolean mIsKeyboardActive = false; //&emsp;輸入法是否激活
    private int mKeyboardHeight = 0; // 輸入法高度

    public KeyboardLayout(Context context) {
        this(context, null, 0);
    }

    public KeyboardLayout(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public KeyboardLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        // 經過視圖樹監聽佈局變化
        getViewTreeObserver().addOnGlobalLayoutListener(new KeyboardOnGlobalChangeListener());
    }

    private class KeyboardOnGlobalChangeListener implements ViewTreeObserver.OnGlobalLayoutListener {

        int mScreenHeight = 0;
        Rect mRect = new Rect();

        private int getScreenHeight() {
            if (mScreenHeight > 0) {
                return mScreenHeight;
            }
            mScreenHeight = ((WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE))
                    .getDefaultDisplay().getHeight();
            return mScreenHeight;
        }

        @Override
        public void onGlobalLayout() {
// // 獲取當前頁面窗口的顯示範圍
            getWindowVisibleDisplayFrame(mRect);

            int screenHeight = getScreenHeight(); //屏幕高度
            int keyboardHeight = screenHeight - mRect.bottom; // 輸入法的高度
            boolean isActive = false;
            if (Math.abs(keyboardHeight) > screenHeight / 5) {
                isActive = true; // 超過屏幕五分之一則表示彈出了輸入法
                mKeyboardHeight = keyboardHeight;
            }
            mIsKeyboardActive = isActive;
            if (mListener != null) {
                mListener.onKeyboardStateChanged(isActive, keyboardHeight);
            }
        }
    }

    public void setKeyboardListener(KeyboardLayoutListener listener) {
        mListener = listener;
    }

    public KeyboardLayoutListener getKeyboardListener() {
        return mListener;
    }

    public boolean isKeyboardActive() {
        return mIsKeyboardActive;
    }

    /** * 獲取輸入法高度 * * @return */
    public int getKeyboardHeight() {
        return mKeyboardHeight;
    }

    public interface KeyboardLayoutListener {
        /** * @param isActive 輸入法是否激活 * @param keyboardHeight 輸入法面板高度 */
        void onKeyboardStateChanged(boolean isActive, int keyboardHeight);
    }

}
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使用

KeyboardLayout加入佈局文件中便可，無其餘使用限制。從代碼中可知，當佈局變化時並不須要知道KeyboardLayout的高度來計算輸入法高度，KeyboardLayout只是充當一個佈局監聽器的做用。android

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent">
...
    <cn.forward.androids.views.KeyboardLayout android:id="@+id/keyboard_layout" android:layout_width="wrap_content" android:layout_height="wrap_content"/>
...
</FrameLayout>
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mKeyboardLayout = (KeyboardLayout) findViewById(R.id.keyboard_layout);
mKeyboardLayout.setKeyboardListener(new KeyboardLayout.KeyboardLayoutListener() {
            @Override
            public void onKeyboardStateChanged(boolean isActive, int keyboardHeight) {
                if (isActive) { // 輸入法打開
                    //do something
                }else {

                }
            }
        });
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輸入法與頁面佈局無縫切換

輸入法和表情欄切換時，若是隻是簡單的在切換到輸入法時隱藏表情欄，或者切換到表情欄時隱藏輸入法，這樣過分過程形成佈局閃爍一下，以下所示：git

這樣的效果簡直會逼死像我這樣有強迫症的人，所以咱們須要解決它！形成這種問題的緣由是，在顯示錶情欄時，輸入法還沒消失，所以表情欄會出如今輸入法上面，當輸入法消失時，表情欄的位置又被從新調整到底部，所以會形成佈局閃爍，同理能夠解釋切換到輸入法時形成閃爍的緣由。解決問題的關鍵主要靠以下兩句代碼：github

// 設置輸入法彈起時自動調整佈局，使之在輸入法之上
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);
// 設置輸入法彈起時不調整當前佈局
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_NOTHING);
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當從輸入法切換到表情欄時，設置佈局爲不會從新調整SOFT_INPUT_ADJUST_NOTHING，同時隱藏輸入法，顯示錶情欄，這樣當再次切換輸入法時，恰好輸入法能夠擋住表情欄，再把佈局設爲可自動調整SOFT_INPUT_ADJUST_RESIZE，代碼以下：微信

public class KeyboardLayoutDemo extends Activity {
    private KeyboardLayout mKeyboardLayout;
    private View mEmojiView;
    private Button mEmojiBtn;
    private EditText mInput;

    int mKeyboardHeight = 400; // 輸入法默認高度爲400

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_keyboard_layout);

        // 起初的佈局可自動調整大小
        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE | WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);

        mKeyboardLayout = (KeyboardLayout) findViewById(R.id.keyboard_layout);
        mEmojiView = findViewById(R.id.emoji);
        mEmojiBtn = (Button) findViewById(R.id.emoji_btn);

        mInput = (EditText) findViewById(R.id.input);

        // 點擊輸入框
        mInput.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mKeyboardLayout.postDelayed(new Runnable() {
                    @Override
                    public void run() { // 輸入法彈出以後，從新調整
                        mEmojiBtn.setSelected(false);
                        mEmojiView.setVisibility(View.GONE);
                        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);
                    }
                }, 250); // 延遲一段時間，等待輸入法徹底彈出
            }
        });

        mEmojiBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mEmojiBtn.setSelected(!mEmojiBtn.isSelected());

                if (mKeyboardLayout.isKeyboardActive()) { // 輸入法打開狀態下
                    if (mEmojiBtn.isSelected()) { // 打開表情
                        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_NOTHING); // 不改變佈局，隱藏鍵盤，emojiView彈出
                        InputMethodManager imm = (InputMethodManager) v.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
                        imm.hideSoftInputFromWindow(mInput.getApplicationWindowToken(), 0);
                        mEmojiView.setVisibility(View.VISIBLE);
                    } else {
                        mEmojiView.setVisibility(View.GONE);
                        InputMethodManager imm = (InputMethodManager) v.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
                        imm.hideSoftInputFromWindow(mInput.getApplicationWindowToken(), 0);
                        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);
                    }
                } else { // 輸入法關閉狀態下
                    if (mEmojiBtn.isSelected()) {
                        // 設置爲不會調整大小，以便輸入彈起時佈局不會改變。若不設置此屬性，輸入法彈起時佈局會閃一下
                        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_NOTHING);
                        mEmojiView.setVisibility(View.VISIBLE);
                    } else {
                        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);
                        mEmojiView.setVisibility(View.GONE);
                    }
                }
            }
        });

        mKeyboardLayout.setKeyboardListener(new KeyboardLayout.KeyboardLayoutListener() {
            @Override
            public void onKeyboardStateChanged(boolean isActive, int keyboardHeight) {

                if (isActive) { // 輸入法打開
                    if (mKeyboardHeight != keyboardHeight) { // 鍵盤發生改變時才設置emojiView的高度，由於會觸發onGlobalLayoutChanged，致使onKeyboardStateChanged再次被調用
                        mKeyboardHeight = keyboardHeight;
                        initEmojiView(); // 每次輸入法彈起時，設置emojiView的高度爲鍵盤的高度，以便下次emojiView彈出時恰好等於鍵盤高度
                    }
                    if (mEmojiBtn.isSelected()) { // 表情打開狀態下
                        mEmojiView.setVisibility(View.GONE);
                        mEmojiBtn.setSelected(false);
                    }
                }
            }
        });
    }

    // 設置表情欄的高度
    private void initEmojiView() {
        ViewGroup.LayoutParams layoutParams = mEmojiView.getLayoutParams();
        layoutParams.height = mKeyboardHeight;
        mEmojiView.setLayoutParams(layoutParams);
    }
}
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