如何在 Android webview 中啟用返回按鈕?
此示例演示瞭如何在 android webview 中啟用返回按鈕。
步驟 1 − 在 Android Studio 中建立新專案,轉到檔案 ⇒ 新專案,並填寫所有必需的詳細資訊以建立新專案。
步驟 2 − 將以下程式碼新增到 res/layout/activity_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:gravity = "center" android:layout_height = "match_parent" tools:context = ".MainActivity" android:orientation = "vertical"> <WebView android:id = "@+id/web_view" android:layout_width = "match_parent" android:layout_height = "match_parent" /> </LinearLayout>
在上述程式碼中,我們採用了 web 檢視來顯示 facebook.com。
步驟 3 − 將以下程式碼新增到 src/MainActivity.java
package com.example.myapplication; import android.app.ProgressDialog; import android.os.Build; import android.os.Bundle; import android.support.annotation.RequiresApi; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.webkit.CookieManager; import android.webkit.WebChromeClient; import android.webkit.WebSettings; import android.webkit.WebView; import android.webkit.WebViewClient; import android.widget.EditText; public class MainActivity extends AppCompatActivity { WebView web_view; @RequiresApi(api = Build.VERSION_CODES.P) @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final ProgressDialog progressDialog = new ProgressDialog(this); progressDialog.setMessage("Loading Data..."); progressDialog.setCancelable(false); web_view = findViewById(R.id.web_view); web_view.setVerticalScrollBarEnabled(true); web_view.requestFocus(); web_view.getSettings().setDefaultTextEncodingName("utf-8"); web_view.getSettings().setJavaScriptEnabled(true); web_view.loadUrl("https://touch.facebook.com/"); web_view.setWebViewClient(new WebViewClient() { @Override public boolean shouldOverrideUrlLoading(WebView view, String url) { view.loadUrl(url); return true; } }); web_view.setWebChromeClient(new WebChromeClient() { public void onProgressChanged(WebView view, int progress) { if (progress < 100) { progressDialog.show(); } if (progress = = 100) { progressDialog.dismiss(); } } }); } @Override public void onBackPressed() { if(web_view!= null && web_view.canGoBack()) web_view.goBack();// if there is previous page open it else super.onBackPressed();//if there is no previous page, close app } }
步驟 4 − 將以下程式碼新增到 AndroidManifest.xml
<?xml version = "1.0" encoding = "utf-8"?> <manifest xmlns:android = "http://schemas.android.com/apk/res/android" package = "com.example.myapplication"> <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>
讓我們嘗試執行你的應用程式。我假設你已將你的實際 Android 移動裝置與電腦連線。要從 android studio 執行應用程式,請開啟一個專案活動檔案,並單擊工具欄中的執行 圖示。選擇你的移動裝置作為選項,然後檢查你的移動裝置,它將顯示你的預設螢幕 −
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