问题

我正在编写一个非常简单的Web视图应用程序，用于向特定类型的用户显示来自Firebase实时数据库的网页。一切都正常，但在关闭应用程序时，用户会被发送回原始的“起始点”页面。我听说你需要使用SharedPreferences来解决这个问题，但如何将它与Firebase关联起来，使一切都正常工作呢？以下是代码示例：

public class TargetActivty extends AppCompatActivity {
    private WebView webView;
    private TextView msgURL;
    private FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance();
    private DatabaseReference reference = firebaseDatabase.getReference();
    private DatabaseReference childReference = reference.child("url");

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_target);
        webView = findViewById(R.id.webView);
        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webView.setWebViewClient(new WebViewClient());
    }

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

    @Override
    protected void onStart() {
        super.onStart();
        childReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                String message = dataSnapshot.getValue(String.class);
                webView.loadUrl(message);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
            }
        });
    }
}

请注意，这段代码主要涉及Firebase数据库和WebView的使用。要解决在应用程序关闭后用户被发送回原始页面的问题，您可以使用SharedPreferences来存储用户的当前位置（URL），然后在应用程序重新打开时将用户重定向到该位置。这需要在适当的地方添加SharedPreferences代码。

public class TargetActivty extends AppCompatActivity {
private WebView webView;
private TextView msgURL;
private FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance();
private DatabaseReference reference = firebaseDatabase.getReference();
private DatabaseReference childReference = reference.child("url");
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_target);
webView = findViewById(R.id.webView);
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);
webView.setWebViewClient(new WebViewClient());
}
@Override
public void onBackPressed() {
if (webView.canGoBack()) {
webView.goBack();
} else {
super.onBackPressed();
}
}
@Override
protected void onStart() {
super.onStart();
childReference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
String message = dataSnapshot.getValue(String.class);
webView.loadUrl(message);
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}}

答案1

得分: 1

使用以下代码：

webView.setWebViewClient(new MyWebViewClient());

class MyWebViewClient extends WebViewClient {

    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {

        view.loadUrl(url);
        return true;

    }

    @Override
    public void onPageFinished(WebView view, String url) {
        super.onPageFinished(view, url);

        // 将最后访问的URL保存到共享首选项
        saveUrl(url);
    }
}

webView.setWebViewClient(new MyWebViewClient());
class MyWebViewClient extends WebViewClient {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
//Save the last visited URL to shared preference
saveUrl(url);
}
}