我正在开发一个应用程序,当我单击 web View 中的链接并期望该方法的结果时,我会在其中执行 Java 方法。在那个方法中,我用 startActivityForResult
开始了另一个 Activity ,它工作得很好(我在那个 Activity 上放了一些日志,一切都很好),但看起来这个方法没有返回任何东西..
这是我的代码:
HTML : (所有包含都可以)
<script type="text/javascript">
$("#run-qrscan").on("click", function(){
var qr_data = window.WebAppInterface.startScan();
// startScan is the Java method I call
// call the function opens the activity etc.. but doesn't get any result
$("#display-qrresult").html(qr_data); // doesn't display anything
});
</script>
我的 Activity :WebActivity.java
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_web);
WebView webview = (WebView) findViewById(R.id.aw_webView);
WebAppInterface jsInterface = new WebAppInterface(this);
webview.getSettings().setJavaScriptEnabled(true);
webview.setWebChromeClient(new WebChromeClient());
webview.addJavascriptInterface(jsInterface, "WebAppInterface");
webview.loadUrl("file:///android_asset/index.html");
}
我的 Javascript 界面:WebAppInterface.java
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.webkit.JavascriptInterface;
public class WebAppInterface {
private static Activity activity;
public static int WEB_APP = 0;
private static int REQUEST_FOR_ACTIVITY_CODE_SCAN = 1000;
private static String qr_data = "";
private static Intent intent;
public WebAppInterface(Activity activity) {
WebAppInterface.activity = activity;
}
@JavascriptInterface
public static String startScan() {
Intent intent = new Intent(activity, ScanActivity.class);
WEB_APP = 1;
activity.startActivityForResult(intent, REQUEST_FOR_ACTIVITY_CODE_SCAN);
//Wait for startActivityForResult to end -since it's asynchronous
while(WEB_APP == 1) {}
Log.d("qr_return", qr_data); // Doesn't display it.
return qr_data; // Empty
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// Scan QR
if (requestCode == REQUEST_FOR_ACTIVITY_CODE_SCAN) {
if (resultCode == Activity.RESULT_OK) {
qr_data = data.getStringExtra("qr_data");
}
}
WEB_APP = 0;
}
}
那我做错了什么?谢谢。
最佳答案
抱歉,我的错,我没有注意到我调用 startActivityForResult
的类只是一个类而不是 Activity.. 所以当返回数据时它不是回到它..
我发布这段代码以防像我这样的人没有注意到这一点。
1- 删除 WebAppInterface.java 类
2- WebActivity.java :
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.Menu;
import android.webkit.JavascriptInterface;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
public class WebActivity extends Activity {
public static int WEB_APP = 0;
private static int REQUEST_FOR_ACTIVITY_CODE_SCAN = 1000;
private static String qr_data = "";
@SuppressLint("SetJavaScriptEnabled")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_web);
WebView webview = (WebView) findViewById(R.id.aw_webView);
WebAppInterface jsInterface = new WebAppInterface();
webview.getSettings().setJavaScriptEnabled(true);
webview.setWebChromeClient(new WebChromeClient());
webview.addJavascriptInterface(jsInterface, "WebAppInterface");
webview.loadUrl("file:///android_asset/index.html");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
return false;
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// Scan QR
if (requestCode == REQUEST_FOR_ACTIVITY_CODE_SCAN) {
if (resultCode == Activity.RESULT_OK) {
qr_data = data.getStringExtra("qr_data");
Log.d("QR", qr_data);
}
}
WEB_APP = 0;
}
public class WebAppInterface {
WebAppInterface() {}
@JavascriptInterface
public String startScan() {
Intent intent = new Intent(WebActivity.this, ScanActivity.class);
WEB_APP = 1;
startActivityForResult(intent, REQUEST_FOR_ACTIVITY_CODE_SCAN);
while(WEB_APP == 1) {}
Log.d("qr_return", qr_data);
return qr_data;
}
}
}
关于java - 无法从 webview android 中从 Javascript 调用的 Java 方法获取数据,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/22594688/