我正在使用以下课程在子浏览器中打开链接，但无法在 Android 上跟踪设备后退按钮事件。我正在使用 showWebPage 方法，因为还有关闭按钮，但我想跟踪设备后退按钮事件。
公共类 ChildBrowser 扩展插件 {
protected static final String LOG_TAG = "ChildBrowser";
private static int CLOSE_EVENT = 0;
private static int LOCATION_CHANGED_EVENT = 1;
private String browserCallbackId = null;
private Dialog dialog;
private WebView webview;
private EditText edittext;
private boolean showLocationBar = true;
/**
* Executes the request and returns PluginResult.
*
* @param action The action to execute.
* @param args JSONArry of arguments for the plugin.
* @param callbackId The callback id used when calling back into JavaScript.
* @return A PluginResult object with a status and message.
*/
public PluginResult execute(String action, JSONArray args, String callbackId) {
PluginResult.Status status = PluginResult.Status.OK;
String result = "";
try {
if (action.equals("showWebPage")) {
this.browserCallbackId = callbackId;
// If the ChildBrowser is already open then throw an error
if (dialog != null && dialog.isShowing()) {
return new PluginResult(PluginResult.Status.ERROR, "ChildBrowser is already open");
}
result = this.showWebPage(args.getString(0), args.optJSONObject(1));
if (result.length() > 0) {
status = PluginResult.Status.ERROR;
return new PluginResult(status, result);
} else {
PluginResult pluginResult = new PluginResult(status, result);
pluginResult.setKeepCallback(true);
return pluginResult;
}
}
else if (action.equals("close")) {
closeDialog();
JSONObject obj = new JSONObject();
obj.put("type", CLOSE_EVENT);
PluginResult pluginResult = new PluginResult(status, obj);
pluginResult.setKeepCallback(false);
return pluginResult;
}
else if (action.equals("openExternal")) {
result = this.openExternal(args.getString(0), args.optBoolean(1));
if (result.length() > 0) {
status = PluginResult.Status.ERROR;
}
}
else {
status = PluginResult.Status.INVALID_ACTION;
}
return new PluginResult(status, result);
} catch (JSONException e) {
return new PluginResult(PluginResult.Status.JSON_EXCEPTION);
}
}
/**
* Display a new browser with the specified URL.
*
* @param url The url to load.
* @param usePhoneGap Load url in PhoneGap webview
* @return "" if ok, or error message.
*/
public String openExternal(String url, boolean usePhoneGap) {
try {
Intent intent = null;
if (usePhoneGap) {
intent = new Intent().setClass(this.ctx.getContext(), org.apache.cordova.DroidGap.class);
intent.setData(Uri.parse(url)); // This line will be removed in future.
intent.putExtra("url", url);
// Timeout parameter: 60 sec max - May be less if http device timeout is less.
intent.putExtra("loadUrlTimeoutValue", 60000);
// These parameters can be configured if you want to show the loading dialog
intent.putExtra("loadingDialog", "Wait,Loading web page..."); // show loading dialog
intent.putExtra("hideLoadingDialogOnPageLoad", true); // hide it once page has completely loaded
}
else {
intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse(url));
}
this.ctx.startActivity(intent);
return "";
} catch (android.content.ActivityNotFoundException e) {
Log.d(LOG_TAG, "ChildBrowser: Error loading url "+url+":"+ e.toString());
return e.toString();
}
}
/**
* Closes the dialog
*/
private void closeDialog() {
if (dialog != null) {
dialog.dismiss();
}
}
/**
* Checks to see if it is possible to go back one page in history, then does so.
*/
private void goBack() {
if (this.webview.canGoBack()) {
this.webview.goBack();
}
}
/**
* Checks to see if it is possible to go forward one page in history, then does so.
*/
private void goForward() {
if (this.webview.canGoForward()) {
this.webview.goForward();
}
}
/**
* Navigate to the new page
*
* @param url to load
*/
private void navigate(String url) {
InputMethodManager imm = (InputMethodManager)this.ctx.getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(edittext.getWindowToken(), 0);
if (!url.startsWith("http") && !url.startsWith("file:")) {
this.webview.loadUrl("http://" + url);
} else {
this.webview.loadUrl(url);
}
this.webview.requestFocus();
}
/**
* Should we show the location bar?
*
* @return boolean
*/
private boolean getShowLocationBar() {
return this.showLocationBar;
}
/**
* Display a new browser with the specified URL.
*
* @param url The url to load.
* @param jsonObject
*/
public String showWebPage(final String url, JSONObject options) {
// Determine if we should hide the location bar.
if (options != null) {
showLocationBar = options.optBoolean("showLocationBar", true);
}
// Create dialog in new thread
Runnable runnable = new Runnable() {
/**
* Convert our DIP units to Pixels
*
* @return int
*/
private int dpToPixels(int dipValue) {
int value = (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_DIP,
(float) dipValue,
ctx.getContext().getResources().getDisplayMetrics()
);
return value;
}
public void run() {
// Let's create the main dialog
dialog = new Dialog(ctx.getContext(), android.R.style.Theme_NoTitleBar);
dialog.getWindow().getAttributes().windowAnimations = android.R.style.Animation_Dialog;
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setCancelable(true);
dialog.setOnDismissListener(new DialogInterface.OnDismissListener() {
public void onDismiss(DialogInterface dialog) {
try {
JSONObject obj = new JSONObject();
obj.put("type", CLOSE_EVENT);
sendUpdate(obj, false);
} catch (JSONException e) {
Log.d(LOG_TAG, "Should never happen");
}
}
});
// Main container layout
LinearLayout main = new LinearLayout(ctx.getContext());
main.setOrientation(LinearLayout.VERTICAL);
// Toolbar layout
RelativeLayout toolbar = new RelativeLayout(ctx.getContext());
toolbar.setLayoutParams(new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT, this.dpToPixels(44)));
toolbar.setPadding(this.dpToPixels(2), this.dpToPixels(2), this.dpToPixels(2), this.dpToPixels(2));
toolbar.setHorizontalGravity(Gravity.LEFT);
toolbar.setVerticalGravity(Gravity.TOP);
// Action Button Container layout
RelativeLayout actionButtonContainer = new RelativeLayout(ctx.getContext());
actionButtonContainer.setLayoutParams(new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
actionButtonContainer.setHorizontalGravity(Gravity.LEFT);
actionButtonContainer.setVerticalGravity(Gravity.CENTER_VERTICAL);
actionButtonContainer.setId(1);
// Back button
ImageButton back = new ImageButton(ctx.getContext());
RelativeLayout.LayoutParams backLayoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.FILL_PARENT);
backLayoutParams.addRule(RelativeLayout.ALIGN_LEFT);
back.setLayoutParams(backLayoutParams);
back.setContentDescription("Back Button");
back.setId(2);
try {
back.setImageBitmap(loadDrawable("www/childbrowser/icon_arrow_left.png"));
} catch (IOException e) {
Log.e(LOG_TAG, e.getMessage(), e);
}
back.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
goBack();
}
});
// Forward button
ImageButton forward = new ImageButton(ctx.getContext());
RelativeLayout.LayoutParams forwardLayoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.FILL_PARENT);
forwardLayoutParams.addRule(RelativeLayout.RIGHT_OF, 2);
forward.setLayoutParams(forwardLayoutParams);
forward.setContentDescription("Forward Button");
forward.setId(3);
try {
forward.setImageBitmap(loadDrawable("www/childbrowser/icon_arrow_right.png"));
} catch (IOException e) {
Log.e(LOG_TAG, e.getMessage(), e);
}
forward.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
goForward();
}
});
// Edit Text Box
edittext = new EditText(ctx.getContext());
RelativeLayout.LayoutParams textLayoutParams = new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
textLayoutParams.addRule(RelativeLayout.RIGHT_OF, 1);
textLayoutParams.addRule(RelativeLayout.LEFT_OF, 5);
edittext.setLayoutParams(textLayoutParams);
edittext.setId(4);
edittext.setSingleLine(true);
edittext.setText(url);
edittext.setInputType(InputType.TYPE_TEXT_VARIATION_URI);
edittext.setImeOptions(EditorInfo.IME_ACTION_GO);
edittext.setInputType(InputType.TYPE_NULL); // Will not except input... Makes the text NON-EDITABLE
edittext.setOnKeyListener(new View.OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
// If the event is a key-down event on the "enter" button
if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
navigate(edittext.getText().toString());
return true;
}
return false;
}
});
// Close button
ImageButton close = new ImageButton(ctx.getContext());
RelativeLayout.LayoutParams closeLayoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.FILL_PARENT);
closeLayoutParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
close.setLayoutParams(closeLayoutParams);
forward.setContentDescription("Close Button");
close.setId(5);
try {
close.setImageBitmap(loadDrawable("www/childbrowser/icon_close.png"));
} catch (IOException e) {
Log.e(LOG_TAG, e.getMessage(), e);
}
close.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
closeDialog();
}
});
// WebView
webview = new WebView(ctx.getContext());
webview.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
webview.setWebChromeClient(new WebChromeClient());
WebViewClient client = new ChildBrowserClient(edittext);
webview.setWebViewClient(client);
WebSettings settings = webview.getSettings();
settings.setJavaScriptEnabled(true);
settings.setJavaScriptCanOpenWindowsAutomatically(true);
settings.setBuiltInZoomControls(true);
settings.setPluginsEnabled(true);
settings.setDomStorageEnabled(true);
webview.loadUrl(url);
webview.setId(6);
webview.getSettings().setLoadWithOverviewMode(true);
webview.getSettings().setUseWideViewPort(true);
webview.requestFocus();
webview.requestFocusFromTouch();
// Add the back and forward buttons to our action button container layout
actionButtonContainer.addView(back);
actionButtonContainer.addView(forward);
// Add the views to our toolbar
toolbar.addView(actionButtonContainer);
toolbar.addView(edittext);
toolbar.addView(close);
// Don't add the toolbar if its been disabled
if (getShowLocationBar()) {
// Add our toolbar to our main view/layout
main.addView(toolbar);
}
// Add our webview to our main view/layout
main.addView(webview);
WindowManager.LayoutParams lp = new WindowManager.LayoutParams();
lp.copyFrom(dialog.getWindow().getAttributes());
lp.width = WindowManager.LayoutParams.FILL_PARENT;
lp.height = WindowManager.LayoutParams.FILL_PARENT;
dialog.setContentView(main);
dialog.show();
dialog.getWindow().setAttributes(lp);
}
private Bitmap loadDrawable(String filename) throws java.io.IOException {
InputStream input = ctx.getAssets().open(filename);
return BitmapFactory.decodeStream(input);
}
};
this.ctx.runOnUiThread(runnable);
return "";
}
/**
* Create a new plugin result and send it back to JavaScript
*
* @param obj a JSONObject contain event payload information
*/
private void sendUpdate(JSONObject obj, boolean keepCallback) {
if (this.browserCallbackId != null) {
PluginResult result = new PluginResult(PluginResult.Status.OK, obj);
result.setKeepCallback(keepCallback);
this.success(result, this.browserCallbackId);
}
}
/**
* The webview client receives notifications about appView
*/
public class ChildBrowserClient extends WebViewClient {
EditText edittext;
/**
* Constructor.
*
* @param mContext
* @param edittext
*/
public ChildBrowserClient(EditText mEditText) {
this.edittext = mEditText;
}
/**
* Notify the host application that a page has started loading.
*
* @param view The webview initiating the callback.
* @param url The url of the page.
*/
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
String newloc;
if (url.startsWith("http:") || url.startsWith("https:") || url.startsWith("file:")) {
newloc = url;
} else {
newloc = "http://" + url;
}
if (!newloc.equals(edittext.getText().toString())) {
edittext.setText(newloc);
}
try {
JSONObject obj = new JSONObject();
obj.put("type", LOCATION_CHANGED_EVENT);
obj.put("location", url);
sendUpdate(obj, true);
} catch (JSONException e) {
Log.d("ChildBrowser", "This should never happen");
}
}
}
}