1, Activity without any processing

The listing file code at this time is as follows:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.chromium.chrome.browser.spacedemo">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

The code of MainActivity.java is as follows:

package org.chromium.chrome.browser.spacedemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

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

At this time, the layout file code of MainActivity is as follows:

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:background="#ff0"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/et_input"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal|bottom"
        android:hint="Please enter content"
        android:text="Hello World!"
        android:textColorHint="#000" />


</LinearLayout>

2, Activity processed

In the manifest file, the corresponding Activity declaration adds the following properties: android:windowSoftInputMode="adjustResize"

Result: ActionBar did not show the situation in the previous section

3, Using the Space control

Although the corresponding attributes are added to the manifest file to avoid the scaling of ActionBar, there are still flaws in the process of adaptation, so the use of Space control here is actually for the purpose of adapting the control, which is better than properties such as Android: layout Ou margin. Its source code is as follows:

package android.widget;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.View;

/**
 * Space is a lightweight View subclass that may be used to create gaps between components
 * in general purpose layouts.
 */
public final class Space extends View {
    /**
     * {@inheritDoc}
     */
    public Space(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        if (getVisibility() == VISIBLE) {
            setVisibility(INVISIBLE);
        }
    }

    /**
     * {@inheritDoc}
     */
    public Space(Context context, AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    /**
     * {@inheritDoc}
     */
    public Space(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    /**
     * {@inheritDoc}
     */
    public Space(Context context) {
        //noinspection NullableProblems
        this(context, null);
    }

    /**
     * Draw nothing.
     *
     * @param canvas an unused parameter.
     */
    @Override
    public void draw(Canvas canvas) {
    }

    /**
     * Compare to: {@link View#getDefaultSize(int, int)}
     * If mode is AT_MOST, return the child size instead of the parent size
     * (unless it is too big).
     */
    private static int getDefaultSize2(int size, int measureSpec) {
        int result = size;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);

        switch (specMode) {
            case MeasureSpec.UNSPECIFIED:
                result = size;
                break;
            case MeasureSpec.AT_MOST:
                result = Math.min(size, specSize);
                break;
            case MeasureSpec.EXACTLY:
                result = specSize;
                break;
        }
        return result;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(
                getDefaultSize2(getSuggestedMinimumWidth(), widthMeasureSpec),
                getDefaultSize2(getSuggestedMinimumHeight(), heightMeasureSpec));
    }
}

It can be found that there is no code in the middle draw of Space, which means that it does not need to render when filling in the layout, which simplifies the filling of the layout.

Reference articles

Application scenario of [Android]Space control