Android WebView 与 URL 输入

Question

我是 android 编程的新手，现在我正在尝试为 android webview 应用程序打下基础。 我想制作一个可以输入URL的起始页，下一页是我之前输入的URL的WebView。 这是我的代码

MainActivity.java

package com.example.app;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebSettings;
import android.webkit.WebView;

public class MainActivity extends Activity {

private WebView mWebView;

@Override
@SuppressLint("SetJavaScriptEnabled")
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mWebView = findViewById(R.id.activity_main_webview);
    WebSettings webSettings = mWebView.getSettings();
    webSettings.setJavaScriptEnabled(true);
    mWebView.setWebViewClient(new MyWebViewClient());

}

public static void getLink(){
    mWebView.loadUrl("https://"+UrlActivity.link.getText().toString());
}

@Override
public void onBackPressed() {
    if(mWebView.canGoBack()) {
        mWebView.goBack();
    } else {
        super.onBackPressed();
    }
}

这是 UrlActivity.java

package com.example.app;

import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class UrlActivity extends MainActivity {
    public static EditText link;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        link = (EditText)findViewById(R.id.link);
        setContentView(R.layout.activity_url);
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    Intent intent = new Intent(UrlActivity.this,MainActivity.class);
                    startActivity(intent);
                }
            },2000);
    }

    public void gotourl(View view){
        if(UrlActivity.link.getText().length() != 0) {
            MainActivity.getLink();
        }else{
            Toast.makeText(this, "Please Enter URL", Toast.LENGTH_SHORT).show();
        }
    }

    public EditText gethost(){
        return link;
    }
}

这是我的 activity_url.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=".UrlActivity">

    <com.google.android.material.textfield.TextInputLayout
        android:id="@+id/textInputLayout"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="1dp"
        android:layout_marginTop="61dp"
        android:layout_marginEnd="1dp"
        android:layout_marginBottom="75dp"
        app:layout_constraintBottom_toTopOf="@+id/logo"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />


    <EditText
        android:id="@+id/link"
        android:layout_width="317dp"
        android:layout_height="62dp"
        android:layout_marginBottom="12dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:text="Enter URL"
        app:layout_constraintBottom_toTopOf="@+id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/logo" />

    <Button
        android:id="@+id/button"

        android:layout_width="106dp"
        android:layout_height="55dp"
        android:layout_marginBottom="301dp"
        android:background="#0250A3"
        android:onClick="gotourl"
        android:text="Enter"
        android:textColor="#FFFFFF"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/link" />

    <ImageView
        android:id="@+id/logo"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="42dp"
        android:layout_marginEnd="42dp"
        android:layout_marginBottom="12dp"
        android:contentDescription="@+logo/"
        app:layout_constraintBottom_toTopOf="@+id/link"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout"
        app:srcCompat="@drawable/otka_space" />

</androidx.constraintlayout.widget.ConstraintLayout>

这是我的 activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.swiperefreshlayout.widget.SwipeRefreshLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/swipe">
        <WebView
            android:id="@+id/activity_main_webview"
            android:layout_width="match_parent"
            android:layout_height="match_parent"></WebView>
    </androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

</LinearLayout>

和这个 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"
    package="com.example.app">

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission
        android:name="android.permission.WRITE_EXTERNAL_STORAGE"
        android:maxSdkVersion="30"
        tools:ignore="ScopedStorage" />

    <application
        android:allowBackup="true"
        android:fullBackupContent="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme"
        android:usesCleartextTraffic="true"
        tools:ignore="GoogleAppIndexingWarning">
        <activity
            android:name=".MainActivity"
            android:configChanges="orientation|screenSize"
            android:label="@string/app_name"></activity>
        <activity android:name=".UrlActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

问题是当我运行它时，应用程序将强制关闭。 当我看到 logcat 时，错误是这样的：

> 2021-08-24 12:05:02.072 27416-27416/com.example.app E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.app, PID: 27416
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.app/com.example.app.UrlActivity}: android.view.InflateException: Binary XML file line #20 in com.example.app:layout/activity_url: Binary XML file line #20 in com.example.app:layout/activity_url: Error inflating class com.google.android.material.textfield.TextInputLayout
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3792)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3968)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2307)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:246)
        at android.app.ActivityThread.main(ActivityThread.java:8506)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
     Caused by: android.view.InflateException: Binary XML file line #20 in com.example.app:layout/activity_url: Binary XML file line #20 in com.example.app:layout/activity_url: Error inflating class com.google.android.material.textfield.TextInputLayout
     Caused by: android.view.InflateException: Binary XML file line #20 in com.example.app:layout/activity_url: Error inflating class com.google.android.material.textfield.TextInputLayout
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Constructor.newInstance0(Native Method)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
        at android.view.LayoutInflater.createView(LayoutInflater.java:852)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:1004)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:959)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1121)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:680)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:532)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:479)
        at com.android.internal.policy.PhoneWindow.setContentView(PhoneWindow.java:541)
        at android.app.Activity.setContentView(Activity.java:3525)
        at com.example.app.UrlActivity.onCreate(UrlActivity.java:16)
        at android.app.Activity.performCreate(Activity.java:8198)
        at android.app.Activity.performCreate(Activity.java:8182)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3765)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3968)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2307)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:246)
        at android.app.ActivityThread.main(ActivityThread.java:8506)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
     Caused by: java.lang.IllegalArgumentException: The style on this component requires your app theme to be Theme.AppCompat (or a descendant).
        at com.google.android.material.internal.ThemeEnforcement.checkTheme(ThemeEnforcement.java:243)
2021-08-24 12:05:02.072 27416-27416/com.example.app E/AndroidRuntime:     at com.google.android.material.internal.ThemeEnforcement.checkAppCompatTheme(ThemeEnforcement.java:213)
        at com.google.android.material.internal.ThemeEnforcement.checkCompatibleTheme(ThemeEnforcement.java:148)
        at com.google.android.material.internal.ThemeEnforcement.obtainTintedStyledAttributes(ThemeEnforcement.java:115)
        at com.google.android.material.textfield.TextInputLayout.<init>(TextInputLayout.java:469)
        at com.google.android.material.textfield.TextInputLayout.<init>(TextInputLayout.java:428)
            ... 28 more
2021-08-24 12:06:01.962 27416-27683/com.example.app E/cr_PlatformSer-Internal: UsageReporting query failed

我应该怎么做才能在我的应用程序中输入 URL 并正常运行？

Answer 1

你必须像这样使用 xml， TextInputLayout需要有一个EditText作为孩子参考这里

<?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=".UrlActivity">

    <com.google.android.material.textfield.TextInputLayout
        android:id="@+id/textInputLayout"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="1dp"
        android:layout_marginTop="61dp"
        android:layout_marginEnd="1dp"
        android:layout_marginBottom="75dp"
        app:layout_constraintBottom_toTopOf="@+id/logo"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">


    <EditText
        android:id="@+id/link"
        android:layout_width="317dp"
        android:layout_height="62dp"
        android:layout_marginBottom="12dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:text="Enter URL"
        app:layout_constraintBottom_toTopOf="@+id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/logo" />
<com.google.android.material.textfield.TextInputLayout>
    <Button
        android:id="@+id/button"

        android:layout_width="106dp"
        android:layout_height="55dp"
        android:layout_marginBottom="301dp"
        android:background="#0250A3"
        android:onClick="gotourl"
        android:text="Enter"
        android:textColor="#FFFFFF"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/link" />

    <ImageView
        android:id="@+id/logo"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="42dp"
        android:layout_marginEnd="42dp"
        android:layout_marginBottom="12dp"
        android:contentDescription="@+logo/"
        app:layout_constraintBottom_toTopOf="@+id/link"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textInputLayout"
        app:srcCompat="@drawable/otka_space" />

</androidx.constraintlayout.widget.ConstraintLayout>