WebView加載網頁（一）

<center>WebView加載網頁</center>

一、新建一個android項目

  新建android項目，應用默認配置，其他地方不做修改。新建一個activity，項目目錄結構爲：

二、修改mainactivity

package cn.qiu.webview2;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private EditText editText;
    private Button button;
    private Button button2;

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

        button=(Button)findViewById(R.id.button);
        editText=(EditText)findViewById(R.id.editText);
        button2=(Button)findViewById(R.id.button2);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final String editTextMes=editText.getText().toString();
                Intent intent=new Intent(MainActivity.this,BaiduActivity.class);
                intent.putExtra("url",editTextMes);
                Toast.makeText(MainActivity.this,editTextMes,Toast.LENGTH_LONG).show();
                startActivity(intent);
            }
        });

        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent(MainActivity.this,LearnActivity.class);
                startActivity(intent);
            }
        });
    }
}

三、修改baiduactivity

package cn.qiu.webview2;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

public class BaiduActivity extends AppCompatActivity {

        private WebView webView;
        private long exitTime = 0;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
                Intent intent=getIntent();
                String url=intent.getStringExtra("url");
                Toast.makeText(BaiduActivity.this,url,Toast.LENGTH_LONG).show();

                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_baidu);
                webView = new WebView(this);
                webView.setWebViewClient(new WebViewClient() {
                        //設置在webView點擊打開的新網頁在當前界面顯示,而不跳轉到新的瀏覽器中
                        @Override
                        public boolean shouldOverrideUrlLoading(WebView view, String url) {
                                view.loadUrl(url);
                                return true;
                        }
                });
                webView.getSettings().setJavaScriptEnabled(true);  //設置WebView屬性,運行執行js腳本
                webView.loadUrl("https://"+url+"/");          //調用loadUrl方法爲WebView加入鏈接
                webView.setWebViewClient(new WebViewClient(){    //
                        @Override
                        public boolean shouldOverrideUrlLoading(WebView view, String url) {

                                try{
                                        if(url.startsWith("baiduboxlite://")||url.startsWith("https://")||url.startsWith("baiduboxapp://")){
                                                Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
                                                startActivity(intent);
                                                return true;
                                        }
                                }catch (Exception e){
                                        return false;
                                }
                                webView.loadUrl(url);
                                return true;
                        }
                });
                setContentView(webView);                           //調用Activity提供的setContentView將webView顯示出來
        }

        //我們需要重寫回退按鈕的時間,當用戶點擊回退按鈕：
        //1.webView.canGoBack()判斷網頁是否能後退,可以則goback()
        //2.如果不可以連續點擊兩次退出App,否則彈出提示Toast
        @Override
        public void onBackPressed() {
                if (webView.canGoBack()) {
                        webView.goBack();
                } else {
                        if ((System.currentTimeMillis() - exitTime) > 2000) {
                                Toast.makeText(getApplicationContext(), "再按一次退出程序",
                                                Toast.LENGTH_SHORT).show();
                                exitTime = System.currentTimeMillis();
                        } else {
                                super.onBackPressed();
                        }

                }
        }

}

四、修改learnactivity

package cn.qiu.webview2;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

public class LearnActivity extends AppCompatActivity {
        private WebView webView;
        private long exitTime = 0;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_learn);
                webView = new WebView(this);
                webView.setWebViewClient(new WebViewClient() {
                        //設置在webView點擊打開的新網頁在當前界面顯示,而不跳轉到新的瀏覽器中
                        @Override
                        public boolean shouldOverrideUrlLoading(WebView view, String url) {
                                view.loadUrl(url);
                                return true;
                        }
                });
                webView.getSettings().setJavaScriptEnabled(true);  //設置WebView屬性,運行執行js腳本
                webView.loadUrl("https://www.yiibai.com/android/");          //調用loadUrl方法爲WebView加入鏈接
                webView.setWebViewClient(new WebViewClient(){    //
                        @Override
                        public boolean shouldOverrideUrlLoading(WebView view, String url) {

                                try{
                                        if(url.startsWith("baiduboxlite://")||url.startsWith("https://")||url.startsWith("baiduboxapp://")||url.startsWith("http://")){
                                                Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
                                                startActivity(intent);
                                                return true;
                                        }
                                }catch (Exception e){
                                        return false;
                                }
                                webView.loadUrl(url);
                                return true;
                        }
                });
                setContentView(webView);                           //調用Activity提供的setContentView將webView顯示出來
        }

        //我們需要重寫回退按鈕的時間,當用戶點擊回退按鈕：
        //1.webView.canGoBack()判斷網頁是否能後退,可以則goback()
        //2.如果不可以連續點擊兩次退出App,否則彈出提示Toast
        @Override
        public void onBackPressed() {
                if (webView.canGoBack()) {
                        webView.goBack();
                } else {
                        if ((System.currentTimeMillis() - exitTime) > 2000) {
                                Toast.makeText(getApplicationContext(), "再按一次退出程序",
                                                Toast.LENGTH_SHORT).show();
                                exitTime = System.currentTimeMillis();
                        } else {
                                super.onBackPressed();
                        }

                }
        }

}

五、修改activy_main.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:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"
        android:orientation="vertical">

        <TextView
                android:layout_width="362dp"
                android:layout_height="wrap_content"
                android:text="請輸入網址：             "
                android:textSize="50px"
                android:textColor="@color/colorAccent"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintRight_toRightOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

        <EditText
                android:layout_width="364dp"
                android:layout_height="wrap_content"
                android:id="@+id/editText"
                android:hint="                       " />

        <Button
                android:id="@+id/button"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="開始訪問"
                android:textSize="40px"
                android:textColor="@color/colorPrimaryDark"/>

        <Button
                android:id="@+id/button2"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Android學習教程"
                android:textColor="@color/colorPrimaryDark"
                android:textSize="30px"
                android:textAllCaps="false"/>

</LinearLayout>

六、baidu_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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"
    tools:context=".BaiduActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_baidu" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        app:srcCompat="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

七、learn_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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"
        tools:context=".LearnActivity">

        <android.support.design.widget.AppBarLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:theme="@style/AppTheme.AppBarOverlay">

                <android.support.v7.widget.Toolbar
                        android:id="@+id/toolbar"
                        android:layout_width="match_parent"
                        android:layout_height="?attr/actionBarSize"
                        android:background="?attr/colorPrimary"
                        app:popupTheme="@style/AppTheme.PopupOverlay" />

        </android.support.design.widget.AppBarLayout>

        <include layout="@layout/content_learn" />

        <android.support.design.widget.FloatingActionButton
                android:id="@+id/fab"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="bottom|end"
                android:layout_margin="@dimen/fab_margin"
                app:srcCompat="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

八、androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="cn.qiu.webview2">

        <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>
                <activity
                        android:name=".BaiduActivity"
                        android:label="@string/title_activity_baidu"
                        android:theme="@style/AppTheme.NoActionBar" />
                <activity
                        android:name=".LearnActivity"
                        android:label="@string/title_activity_learn"
                        android:theme="@style/AppTheme.NoActionBar"></activity>
        </application>

</manifest>

九、運行效果

1、首頁

2、百度頁面

3、Android學習頁面