public class CallbackContext {
private static final String LOG_TAG = "CordovaPlugin";
private String callbackId;
private CordovaWebView webView;
private boolean finished;
private int changingThreads;
public CallbackContext(String callbackId, CordovaWebView webView) {
this.callbackId = callbackId;
this.webView = webView;
}
public boolean isFinished() {
return finished;
}
public boolean isChangingThreads() {
return changingThreads > 0;
}
public String getCallbackId() {
return callbackId;
}
public void sendPluginResult(PluginResult pluginResult) {
synchronized (this) {
if (finished) {
Log.w(LOG_TAG, "Attempted to send a second callback for ID: " + callbackId + "\nResult was: " + pluginResult.getMessage());
return;
} else {
finished = !pluginResult.getKeepCallback();
}
}
webView.sendPluginResult(pluginResult, callbackId);
}
/**
* Helper for success callbacks that just returns the Status.OK by default
*
* @param message The message to add to the success result.
*/
public void success(JSONObject message) {
sendPluginResult(new PluginResult(PluginResult.Status.OK, message));
}
/**
* Helper for success callbacks that just returns the Status.OK by default
*
* @param message The message to add to the success result.
*/
public void success(String message) {
sendPluginResult(new PluginResult(PluginResult.Status.OK, message));
}
/**
* Helper for success callbacks that just returns the Status.OK by default
*
* @param message The message to add to the success result.
*/
public void success(JSONArray message) {
sendPluginResult(new PluginResult(PluginResult.Status.OK, message));
}
/**
* Helper for success callbacks that just returns the Status.OK by default
*
* @param message The message to add to the success result.
*/
public void success(byte[] message) {
sendPluginResult(new PluginResult(PluginResult.Status.OK, message));
}
/**
* Helper for success callbacks that just returns the Status.OK by default
*
* @param message The message to add to the success result.
*/
public void success(int message) {
sendPluginResult(new PluginResult(PluginResult.Status.OK, message));
}
/**
* Helper for success callbacks that just returns the Status.OK by default
*/
public void success() {
sendPluginResult(new PluginResult(PluginResult.Status.OK));
}
/**
* Helper for error callbacks that just returns the Status.ERROR by default
*
* @param message The message to add to the error result.
*/
public void error(JSONObject message) {
sendPluginResult(new PluginResult(PluginResult.Status.ERROR, message));
}
/**
* Helper for error callbacks that just returns the Status.ERROR by default
*
* @param message The message to add to the error result.
*/
public void error(String message) {
sendPluginResult(new PluginResult(PluginResult.Status.ERROR, message));
}
/**
* Helper for error callbacks that just returns the Status.ERROR by default
*
* @param message The message to add to the error result.
*/
public void error(int message) {
sendPluginResult(new PluginResult(PluginResult.Status.ERROR, message));
}
}
关键代码在于sendPluginResult，最终调用webView.sendPluginResult(pluginResult, callbackId);
这里就把结果返回给了CordovaWebview.什么都不用说，进去看看是什么鬼？ /**
* Send a plugin result back to Javascript.
* (This is a convenience method)
*
* @param result
* @param callbackId
*/
public void sendPluginResult(PluginResult result, String callbackId) {
this.bridge.getMessageQueue().addPluginResult(result, callbackId);
}
这里就回到了我们初始化时的CordovaBridge,获得NativeToJsMessageQueue，并且添加一个pluginResult.public void addPluginResult(PluginResult result, String callbackId) {
if (callbackId == null) {
Log.e(LOG_TAG, "Got plugin result with no callbackId", new Throwable());
return;
}
// Don't send anything if there is no result and there is no need to
// clear the callbacks.
boolean noResult = result.getStatus() == PluginResult.Status.NO_RESULT.ordinal();
boolean keepCallback = result.getKeepCallback();
if (noResult && keepCallback) {
return;
}
JsMessage message = new JsMessage(result, callbackId);
if (FORCE_ENCODE_USING_EVAL) {
StringBuilder sb = new StringBuilder(message.calculateEncodedLength() + 50);
message.encodeAsJsMessage(sb);
message = new JsMessage(sb.toString());
}
enqueueMessage(message);
}
private void enqueueMessage(JsMessage message) {
synchronized (this) {
if (activeBridgeMode == null) {
Log.d(LOG_TAG, "Dropping Native->JS message due to disabled bridge");
return;
}
queue.add(message);
if (!paused) {
activeBridgeMode.onNativeToJsMessageAvailable();
}
}
} 把一个JsMessage放入到队列中，并且调用onNativeToJsMessageAvailable
/**
* The list of Javascript statements to be sent to Javascript.
*/
private final LinkedList queue = new LinkedList();
这些bridgeMode是在NativeToJsMessageQueue时初始化创建出来的：public NativeToJsMessageQueue(CordovaWebView webView, CordovaInterface cordova) {
this.cordova = cordova;
this.webView = webView;
registeredListeners = new BridgeMode[4];
registeredListeners[0] = new PollingBridgeMode();
registeredListeners[1] = new LoadUrlBridgeMode();
registeredListeners[2] = new OnlineEventsBridgeMode();
registeredListeners[3] = new PrivateApiBridgeMode();
reset();
}
具体用到哪一个，需要根据当时情况。
private abstract class BridgeMode {
abstract void onNativeToJsMessageAvailable();
void notifyOfFlush(boolean fromOnlineEvent) {}
void reset() {}
}
/** Uses JS polls for messages on a timer.. */
private class PollingBridgeMode extends BridgeMode {
@Override void onNativeToJsMessageAvailable() {
}
}
/** Uses webView.loadUrl("Javascript:") to execute messages. */
private class LoadUrlBridgeMode extends BridgeMode {
final Runnable runnable = new Runnable() {
public void run() {
String js = popAndEncodeAsJs();
if (js != null) {
webView.loadUrlNow("Javascript:" + js);
}
}
};
@Override void onNativeToJsMessageAvailable() {
cordova.getActivity().runOnUiThread(runnable);
}
}
/** Uses online/offline events to tell the JS when to poll for messages. */
private class OnlineEventsBridgeMode extends BridgeMode {
private boolean online;
private boolean ignoreNextFlush;
final Runnable toggleNetworkRunnable = new Runnable() {
public void run() {
if (!queue.isEmpty()) {
ignoreNextFlush = false;
webView.setNetworkAvailable(online);
}
}
};
final Runnable resetNetworkRunnable = new Runnable() {
public void run() {
Online= false;
// If the following call triggers a notifyOfFlush, then ignore it.
ignoreNextFlush = true;
webView.setNetworkAvailable(true);
}
};
@Override void reset() {
cordova.getActivity().runOnUiThread(resetNetworkRunnable);
}
@Override void onNativeToJsMessageAvailable() {
cordova.getActivity().runOnUiThread(toggleNetworkRunnable);
}
// Track when online/offline events are fired so that we don't fire excess events.
@Override void notifyOfFlush(boolean fromOnlineEvent) {
if (fromOnlineEvent && !ignoreNextFlush) {
Online= !online;
}
}
}
/**
* Uses Java reflection to access an API that lets us eval JS.
* Requires Android 3.2.4 or above.
*/
private class PrivateApiBridgeMode extends BridgeMode {
// Message added in commit:
// http://omapzoom.org/?p=platform/frameworks/base.git;a=commitdiff;h=9497c5f8c4bc7c47789e5ccde01179abc31ffeb2
// Which first appeared in 3.2.4ish.
private static final int EXECUTE_JS = 194;
Method sendMessageMethod;
Object webViewCore;
boolean initFailed;
@SuppressWarnings("rawtypes")
private void initReflection() {
Object webViewObject = webView;
Class webViewClass = WebView.class;
try {
Field f = webViewClass.getDeclaredField("mProvider");
f.setAccessible(true);
webViewObject = f.get(webView);
webViewClass = webViewObject.getClass();
} catch (Throwable e) {
// mProvider is only required on newer Android releases.
}
try {
Field f = webViewClass.getDeclaredField("mWebViewCore");
f.setAccessible(true);
webViewCore = f.get(webViewObject);
if (webViewCore != null) {
sendMessageMethod = webViewCore.getClass().getDeclaredMethod("sendMessage", Message.class);
sendMessageMethod.setAccessible(true);
}
} catch (Throwable e) {
initFailed = true;
Log.e(LOG_TAG, "PrivateApiBridgeMode failed to find the expected APIs.", e);
}
}
@Override void onNativeToJsMessageAvailable() {
if (sendMessageMethod == null && !initFailed) {
initReflection();
}
// webViewCore is lazily initialized, and so may not be available right away.
if (sendMessageMethod != null) {
String js = popAndEncodeAsJs();
Message execJsMessage = Message.obtain(null, EXECUTE_JS, js);
try {
sendMessageMethod.invoke(webViewCore, execJsMessage);
} catch (Throwable e) {
Log.e(LOG_TAG, "Reflection message bridge failed.", e);
}
}
}
}
回头看看这个方法就知道用哪个：
public String promptOnJsPrompt(String origin, String message, String defaultValue) {
if (defaultValue != null && defaultValue.length() > 3 && defaultValue.startsWith("gap:")) {
JSONArray array;
try {
array = new JSONArray(defaultValue.substring(4));
int bridgeSecret = array.getInt(0);
String service = array.getString(1);
String action = array.getString(2);
String callbackId = array.getString(3);
String r = jsExec(bridgeSecret, service, action, callbackId, message);
return r == null ? "" : r;
} catch (JSONException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return "";
}
// Sets the native->JS bridge mode.
else if (defaultValue != null && defaultValue.startsWith("gap_bridge_mode:")) {
try {
int bridgeSecret = Integer.parseInt(defaultValue.substring(16));
jsSetNativeToJsBridgeMode(bridgeSecret, Integer.parseInt(message));
} catch (NumberFormatException e){
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return "";
}
// Polling for Javascript messages
else if (defaultValue != null && defaultValue.startsWith("gap_poll:")) {
int bridgeSecret = Integer.parseInt(defaultValue.substring(9));
try {
String r = jsRetrieveJsMessages(bridgeSecret, "1".equals(message));
return r == null ? "" : r;
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return "";
}
else if (defaultValue != null && defaultValue.startsWith("gap_init:")) {
// Protect against random iframes being able to talk through the bridge.
// Trust only file URLs and the start URL's domain.
// The extra origin.startsWith("http") is to protect against iframes with data: having "" as origin.
if (origin.startsWith("file:") || (origin.startsWith("http") && loadedUrl.startsWith(origin))) {
// Enable the bridge
int bridgeMode = Integer.parseInt(defaultValue.substring(9));
jsMessageQueue.setBridgeMode(bridgeMode);
// Tell JS the bridge secret.
int secret = generateBridgeSecret();
return ""+secret;
} else {
Log.e(LOG_TAG, "gap_init called from restricted origin: " + origin);
}
return "";
}
return null;
} 这里会解析Js传过来的参数，然后可以判断出使用哪个。 这节分析到此.......
京公网安备 11010802041100号 | 京ICP备19059560号-4 | PHP1.CN 第一PHP社区 版权所有