the web page is displayed in the webView when the button is clicked. 当点击按钮时在webView显示网页。

[cleversheep2011]

The following questions are from machine translation, please understand if there is any translation error.

Hello! Recently I have had some problems learning Android. When the following code runs, the webView control doesn't display or only shows a white screen, I want it to appear on the screen. What to do?

你好！最近我在学习Android时遇到了一些问题。以下代码运行时，webView 控件不显示或仅显示白屏，我希望它显示在屏幕上。怎么办？

====MainActivity.java====
package com.example.myapplication;
import android.view.View;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.*;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {

    private WebView webView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        webView = (WebView) findViewById(R.id.webView);
        webView.getSettings().setAllowFileAccess(true);
        webView.getSettings().setBuiltInZoomControls(true);
        webView.setWebViewClient(new HelloWebViewClient());
        Button btn1 = (Button) findViewById(R.id.button1);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                webView.loadUrl("https://afdian.net/a/cleversheep");
            }
        });
        Button btn2 = (Button) findViewById(R.id.button2);
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                webView.loadUrl("https://afdian.net/a/DYC668YSZC");
            }
        });
    }
    private class HelloWebViewClient extends WebViewClient {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }
    }
}

====activity_main.xml====
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="绵羊云app"
        android:textSize="50dp"
        android:textStyle="bold"
        tools:ignore="MissingConstraints" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="400dp"
        android:layout_height="wrap_content"
        android:text="这个app还在测试 只能看看 你可以查看绵羊云工作室的官网:sheepyun.top 备用网址:yuncheng.fun"
        android:textSize="20dp"
        app:layout_constraintStart_toStartOf="@+id/textView1"
        app:layout_constraintTop_toBottomOf="@+id/textView1"
        tools:ignore="MissingConstraints" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="sheep的爱发电"
        app:layout_constraintEnd_toStartOf="@+id/button2"
        app:layout_constraintHorizontal_bias="0.56"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2"
        tools:ignore="MissingConstraints" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="48dp"
        android:text="小云的爱发电"
        app:layout_constraintBottom_toBottomOf="@+id/button1"
        app:layout_constraintEnd_toEndOf="@+id/textView2" />

    <WebView
        android:id="@+id/webView"
        android:layout_width="409dp"
        android:layout_height="529dp"
        app:layout_constraintTop_toBottomOf="@+id/button1"
        tools:layout_editor_absoluteX="1dp" />

</androidx.constraintlayout.widget.ConstraintLayout>

====AndroidManifest.xml====
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/icon_round"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/Theme.MyApplication"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        </activity>
    </application>
    <uses-permission android:name="android.permission.INTERNET" />

</manifest>

I created two buttons and asked them to display the page whenever they clicked

我创建了两个按钮，并要求它们在单击时显示页面

[cleversheep2011]

I'm a primary school student, so my English is not good, I use machine translation to generate this text, if there is an error, please understand

[Eross220]

I have checked your requirements.
I can fix your problem.
Please feel free to contact me if you would like.
my skype id is live:.cid.2a415ab05458e6ac.
Best regards.

[cleversheep2011]

我已经检查了您的要求。我可以解决你的问题。如果您愿意，请随时与我联系。我的Skype ID是实时的：.cid.2a415ab05458e6ac。 此致敬意。

Sorry, Skype doesn't work on my computer, so I can't contact you.If I can open it, I'll contact you!

[Yu2002s]

webview设置项少了