Android输入法弹出时覆盖输入框问题

当一个activity中有输入框时，点击输入框，会弹出输入法，界面的变动与manifest中对应的android:windowSoftInputMode有关，一般可以设置的值如下，

<activity android:windowSoftInputMode=[
"stateUnspecified",
"stateUnchanged”, 
"stateHidden",
"stateAlwaysHidden”, 
"stateVisible",
"stateAlwaysVisible”, 
"adjustUnspecified",
"adjustResize”, 
"adjustPan"] …… >

具体怎么设置可以从官方文档查看。今天主要解决当输入法弹出时覆盖输入框的问题

当android应用中如果一个activity设置了全屏属性Theme.Light.NotittleBar.Fullscreen或者设置了Theme的true，对应的页面上如果有输入框，将会导致点击输入框时软键盘弹出后覆盖输入框，当时输入框看不见。

这其实是因为在全屏时，adjustResize属性不在有效，只能使用adjustPan属性，当时往往adjustPan达不到效果，因为页面会整体平移留出输入框，体验效果很差。该问题是系统的一个bug，参考链接.

可以采用如下方案解决：
如果跟布局采用FrameLayout，则可以复写一个自定义FrameLayout，同时设置android:fitsSystemWindows属性

<com.sample.ui.widget.InsetFrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"
                   android:fitsSystemWindows="true”>

com.sample.ui.widget.InsetFrameLayout 代码如下：

public final class InsetFrameLayout extends FrameLayout {
    private int[] mInsets = new int[4];

    public InsetFrameLayout(Context context) {
        super(context);
    }

    public InsetFrameLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public InsetFrameLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public final int[] getInsets() {
        return mInsets;
    }

    @Override
    protected final boolean fitSystemWindows(Rect insets) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            // Intentionally do not modify the bottom inset. For some reason,
            // if the bottom inset is modified, window resizing stops working.

            mInsets[0] = insets.left;
            mInsets[1] = insets.top;
            mInsets[2] = insets.right;

            insets.left = 0;
            insets.top = 0;
            insets.right = 0;
        }

        return super.fitSystemWindows(insets);
    }
    @Override
    public final WindowInsets onApplyWindowInsets(WindowInsets insets) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH) {
            mInsets[0] = insets.getSystemWindowInsetLeft();
            mInsets[1] = insets.getSystemWindowInsetTop();
            mInsets[2] = insets.getSystemWindowInsetRight();
            return super.onApplyWindowInsets(insets.replaceSystemWindowInsets(0, 0, 0,
                    insets.getSystemWindowInsetBottom()));
        } else {
            return insets;
        }
    }

}

同时官方也给出了解决方案：

/* * Copyright 2014 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */

package com.google.samples.apps.iosched.ui.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.widget.FrameLayout;

import com.google.samples.apps.iosched.R;

/** * A layout that draws something in the insets passed to {@link #fitSystemWindows(Rect)}, i.e. the area above UI chrome * (status and navigation bars, overlay action bars). */
@Deprecated
public class ScrimInsetsFrameLayout extends FrameLayout {
    private Drawable mInsetForeground;

    private Rect mInsets;
    private Rect mTempRect = new Rect();
    private OnInsetsCallback mOnInsetsCallback;

    public ScrimInsetsFrameLayout(Context context) {
        super(context);
        init(context, null, 0);
    }

    public ScrimInsetsFrameLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs, 0);
    }

    public ScrimInsetsFrameLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs, defStyle);
    }

    private void init(Context context, AttributeSet attrs, int defStyle) {
        final TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.ScrimInsetsView, defStyle, 0);
        if (a == null) {
            return;
        }
        mInsetForeground = a.getDrawable(R.styleable.ScrimInsetsView_appInsetForeground);
        a.recycle();

        setWillNotDraw(true);
    }

    @Override
    protected boolean fitSystemWindows(Rect insets) {
        mInsets = new Rect(insets);
        setWillNotDraw(mInsetForeground == null);
        ViewCompat.postInvalidateOnAnimation(this);
        if (mOnInsetsCallback != null) {
            mOnInsetsCallback.onInsetsChanged(insets);
        }
        return true; // consume insets
    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);

        int width = getWidth();
        int height = getHeight();
        if (mInsets != null && mInsetForeground != null) {
            int sc = canvas.save();
            canvas.translate(getScrollX(), getScrollY());

            // Top
            mTempRect.set(0, 0, width, mInsets.top);
            mInsetForeground.setBounds(mTempRect);
            mInsetForeground.draw(canvas);

            // Bottom
            mTempRect.set(0, height - mInsets.bottom, width, height);
            mInsetForeground.setBounds(mTempRect);
            mInsetForeground.draw(canvas);

            // Left
            mTempRect.set(0, mInsets.top, mInsets.left, height - mInsets.bottom);
            mInsetForeground.setBounds(mTempRect);
            mInsetForeground.draw(canvas);

            // Right
            mTempRect.set(width - mInsets.right, mInsets.top, width, height - mInsets.bottom);
            mInsetForeground.setBounds(mTempRect);
            mInsetForeground.draw(canvas);

            canvas.restoreToCount(sc);
        }
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        if (mInsetForeground != null) {
            mInsetForeground.setCallback(this);
        }
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        if (mInsetForeground != null) {
            mInsetForeground.setCallback(null);
        }
    }

    /** * Allows the calling container to specify a callback for custom processing when insets change (i.e. when * {@link #fitSystemWindows(Rect)} is called. This is useful for setting padding on UI elements based on * UI chrome insets (e.g. a Google Map or a ListView). When using with ListView or GridView, remember to set * clipToPadding to false. */
    public void setOnInsetsCallback(OnInsetsCallback onInsetsCallback) {
        mOnInsetsCallback = onInsetsCallback;
    }

    public static interface OnInsetsCallback {
        public void onInsetsChanged(Rect insets);
    }
}

采用如上其中一种方法就可以解决输入法弹出后覆盖输入框问题。