0. 参考资料:
《第一行代码》
《Android程序设计与开发》刘国柱等编
net::ERR_CLEARTEXT_NOT_PERMITTED 错误解决方法:
[简单]
详细方案
1. WebView基础
2. 实例分析(1)
XML文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/webView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
></WebView>
</LinearLayout>
java文件
package com.example.a1104.myapplication;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WebView webView= (WebView)findViewById(R.id.webView1);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebViewClient(new WebViewClient());
webView.loadUrl("http://www.baidu.com");
}
}
权限设置 <uses-permission android:name="android.permission.INTERNET"/>
在权限设置中加入:<application android:usesCleartextTraffic="true"
即可
另一种解决方法:
Create file res/xml/network_security_config.xml -
<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
<domain-config cleartextTrafficPermitted="true">
<domain includeSubdomains="true">Your URL(ex: 127.0.0.1)</domain>
</domain-config>
</network-security-config>
AndroidManifest.xml -
<?xml version="1.0" encoding="utf-8"?>
<manifest ...>
<uses-permission android:name="android.permission.INTERNET" />
<application
...
android:networkSecurityConfig="@xml/network_security_config"
...>
...
</application>
</manifest>
3. 实例分析(2)
XML文件:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_height="match_parent"
android:layout_width="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<EditText
android:id="@+id/url"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="www.baidu.com"/>
<Button
android:id="@+id/connect"
android:text="链接地址"
android:layout_width="99dp"
android:layout_height="wrap_content" />
</LinearLayout>
<WebView
android:id="@+id/show"
android:layout_marginTop="10dp"
android:layout_width="match_parent"
android:layout_height="match_parent">
</WebView>
</LinearLayout>
权限配置
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:usesCleartextTraffic="true"
//注意若不加此行会出现 net::ERR_CLEARTEXT_NOT_PERMITTED错误
java文件
package com.example.a1104.myapplication;
import android.graphics.Bitmap;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
private EditText url;
private WebView show;
private Button connect;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//获取页面中的元素
url = (EditText)findViewById(R.id.url);
show = (WebView)findViewById(R.id.show);
connect = (Button)findViewById(R.id.connect);
WebSettings webSettings = show.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setAllowFileAccess(true); //设置可以访问文件
webSettings.setBuiltInZoomControls(true); //设置支持缩放
//设置WebViewClient
show.setWebViewClient(new WebViewClient(){
public boolean shouldOverrideUrlLoading(WebView view,String url){
view.loadUrl(url);
return true;
}
@Override
public void onPageFinished(WebView view,String url){
super.onPageFinished(view,url);
}
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon){
super.onPageStarted(view,url,favicon);
}
});
connect.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String urlStr = url.getText().toString();
show.loadUrl("https://" + urlStr);
}
});
}
}
成功访问
如果不加权限设置中的这一行 android:usesCleartextTraffic="true"
从Android 9.0(API级别28)开始,默认情况下禁用明文支持。因此http的url均无法在webview中加载
我遇到的情况:第一次编译时,不可用,出现错误(首页可见,但是首页上面的链接无法用):ERR_CLEARTEXT_NOT_PERMITTED错误。
将上一行删除后,再次编译,却正常。
案例三:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/webView"
android:layout_width="match_parent"
android:layout_height="match_parent"
></WebView>
</LinearLayout>
Java中
package com.example.a1104.myapplication;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
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().setJavaScriptEnabled(true);
//调用了shouldOverrideUrlLoading
webView.setWebViewClient(new WebViewClient(){
@Override
public boolean shouldOverrideUrlLoading(WebView view,String url){
view.loadUrl(url);
return true;
}
});
webView.loadUrl("http://www.baidu.com");
}
}
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:usesCleartextTraffic="true"