無風的日子

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.XXX">
    <uses-permission android:name="android.permission.INTERNET"/>
    <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>

package com.example.xxx;

import android.app.ProgressDialog;
import android.content.pm.ActivityInfo;
import android.graphics.Bitmap;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebSettings;
import android.webkit.WebViewClient;

public class MainActivity extends AppCompatActivity {

    WebView web_view;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        web_view = (WebView) findViewById(R.id.web_view);
        web_view.getSettings().setBuiltInZoomControls(true);
        web_view.getSettings().setJavaScriptEnabled(true);
        web_view.setWebViewClient(new WebViewClient());
        web_view.loadUrl("https://sites.google.com/");
    }

    public void onBackPressed() {
        if (web_view.canGoBack()) {
            web_view.goBack();
            return;
        }
        super.onBackPressed();
    }
}