JsCallJava.java

package com.minggo.pluto.util;

import android.text.TextUtils;
import android.util.Log;
import android.webkit.WebView;

import com.google.gson.Gson;

import org.json.JSONArray;
import org.json.JSONObject;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;

/**
 * JS调用java
 * 
 * @author minggo
 * @time 2015-5-8上午10:50:26
 */
public class JsCallJava {
	private final static String TAG = "JsCallJava";
	private final static String RETURN_RESULT_FORMAT = "{\"code\": %d, \"result\": %s}";
	private HashMap<String, Method> mMethodsMap;
	private String mInjectedName;
	private String mPreloadInterfaceJS;
	private Gson mGson;

	public JsCallJava(String injectedName, Class injectedCls) {
		try {
			if (TextUtils.isEmpty(injectedName)) {
				throw new Exception("injected name can not be null");
			}
			mInjectedName = injectedName;
			mMethodsMap = new HashMap<String, Method>();
			// 获取自身声明的所有方法（包括public private protected）， getMethods会获得所有继承与非继承的方法
			Method[] methods = injectedCls.getDeclaredMethods();

			StringBuilder sb = new StringBuilder("javascript:(function(b){console.log(\"");
			sb.append(mInjectedName);
			sb.append(" initialization begin\");var a={queue:[],callback:function(){var d=Array.prototype.slice.call(arguments,0);var c=d.shift();var e=d.shift();this.queue[c].apply(this,d);if(!e){delete this.queue[c]}}};");

			//LogUtils.info("WebView", "methods有获取" + methods.length);

			for (Method method : methods) {
				method.setAccessible(true);
				String sign = null;
				// method.getModifiers() != (Modifier.PUBLIC | Modifier.STATIC)
				// ||
				if (method.getModifiers() != (Modifier.PUBLIC | Modifier.STATIC)
						|| (sign = genJavaMethodSign(method)) == null) {
					//LogUtils.info("WebView", "没有获取" + sign);
					continue;
				}
				//LogUtils.info("WebView", "获取" + sign);
				mMethodsMap.put(sign, method);
				sb.append(String.format("a.%s=", method.getName()));
			}

			sb.append("function(){var f=Array.prototype.slice.call(arguments,0);if(f.length<1){throw\"");
			sb.append(mInjectedName);
			sb.append(" call error, message:miss method name\"}var e=[];for(var h=1;h<f.length;h++){var c=f[h];var j=typeof c;e[e.length]=j;if(j==\"function\"){var d=a.queue.length;a.queue[d]=c;f[h]=d}}var g=JSON.parse(prompt(JSON.stringify({method:f.shift(),types:e,args:f})));if(g.code!=200){throw\"");
			sb.append(mInjectedName);
			sb.append(" call error, code:\"+g.code+\", message:\"+g.result}return g.result};Object.getOwnPropertyNames(a).forEach(function(d){var c=a[d];if(typeof c===\"function\"&&d!==\"callback\"){a[d]=function(){return c.apply(a,[d].concat(Array.prototype.slice.call(arguments,0)))}}});b.");
			sb.append(mInjectedName);
			sb.append("=a;console.log(\"");
			sb.append(mInjectedName);
			sb.append(" initialization end\")})(window);");
			mPreloadInterfaceJS = sb.toString();
		} catch (Exception e) {
			Log.e(TAG, "init js error:" + e.getMessage());
		}
	}

	private String genJavaMethodSign(Method method) {
		String sign = method.getName();
		method.setAccessible(true);
		Class[] argsTypes = method.getParameterTypes();
		int len = argsTypes.length;
		if (len < 1 || argsTypes[0] != WebView.class) {
			Log.w(TAG, "method(" + sign + ") must use webview to be first parameter, will be pass");
			return null;
		}
		for (int k = 1; k < len; k++) {
			Class cls = argsTypes[k];
			if (cls == String.class) {
				sign += "_S";
			} else if (cls == int.class || cls == long.class || cls == float.class || cls == double.class) {
				sign += "_N";
			} else if (cls == boolean.class) {
				sign += "_B";
			} else if (cls == JSONObject.class) {
				sign += "_O";
			} else if (cls == JsCallback.class) {
				sign += "_F";
			} else {
				sign += "_P";
			}
		}
		return sign;
	}

	public String getPreloadInterfaceJS() {
		return mPreloadInterfaceJS;
	}

	public String call(WebView webView, String jsonStr) {
		if (!TextUtils.isEmpty(jsonStr)) {
			try {
				JSONObject callJson = new JSONObject(jsonStr);
				String methodName = callJson.getString("method");
				JSONArray argsTypes = callJson.getJSONArray("types");
				JSONArray argsVals = callJson.getJSONArray("args");
				String sign = methodName;
				int len = argsTypes.length();
				Object[] values = new Object[len + 1];
				int numIndex = 0;
				String currType;

				values[0] = webView;

				for (int k = 0; k < len; k++) {
					currType = argsTypes.optString(k);
					if ("string".equals(currType)) {
						sign += "_S";
						values[k + 1] = argsVals.isNull(k) ? null : argsVals.getString(k);
					} else if ("number".equals(currType)) {
						sign += "_N";
						numIndex = numIndex * 10 + k + 1;
					} else if ("boolean".equals(currType)) {
						sign += "_B";
						values[k + 1] = argsVals.getBoolean(k);
					} else if ("object".equals(currType)) {
						sign += "_O";
						values[k + 1] = argsVals.isNull(k) ? null : argsVals.getJSONObject(k);
					} else if ("function".equals(currType)) {
						sign += "_F";
						values[k + 1] = new JsCallback(webView, mInjectedName, argsVals.getInt(k));
					} else {
						sign += "_P";
					}
				}

				Method currMethod = mMethodsMap.get(sign);

				// 方法匹配失败
				if (currMethod == null) {
					return getReturn(jsonStr, 500, "not found method(" + sign + ") with valid parameters");
				}
				// 数字类型细分匹配
				if (numIndex > 0) {
					Class[] methodTypes = currMethod.getParameterTypes();
					int currIndex;
					Class currCls;
					while (numIndex > 0) {
						currIndex = numIndex - numIndex / 10 * 10;
						currCls = methodTypes[currIndex];
						if (currCls == int.class) {
							values[currIndex] = argsVals.getInt(currIndex - 1);
						} else if (currCls == long.class) {
							// WARN: argsJson.getLong(k + defValue) will return
							// a bigger incorrect number
							values[currIndex] = Long.parseLong(argsVals.getString(currIndex - 1));
						} else {
							values[currIndex] = argsVals.getDouble(currIndex - 1);
						}
						numIndex /= 10;
					}
				}

				return getReturn(jsonStr, 200, currMethod.invoke(null, values));
			} catch (Exception e) {
				// 优先返回详细的错误信息
				if (e.getCause() != null) {
					return getReturn(jsonStr, 500, "method execute error:" + e.getCause().getMessage());
				}
				return getReturn(jsonStr, 500, "method execute error:" + e.getMessage());
			}
		} else {
			return getReturn(jsonStr, 500, "call data empty");
		}
	}

	private String getReturn(String reqJson, int stateCode, Object result) {
		String insertRes;
		if (result == null) {
			insertRes = "null";
		} else if (result instanceof String) {
			result = ((String) result).replace("\"", "\\\"");
			insertRes = "\"" + result + "\"";
		} else if (!(result instanceof Integer) && !(result instanceof Long) && !(result instanceof Boolean)
				&& !(result instanceof Float) && !(result instanceof Double) && !(result instanceof JSONObject)) { // 非数字或者非字符串的构造对象类型都要序列化后再拼接
			if (mGson == null) {
				mGson = new Gson();
			}
			insertRes = mGson.toJson(result);
		} else { // 数字直接转化
			insertRes = String.valueOf(result);
		}
		String resStr = String.format(RETURN_RESULT_FORMAT, stateCode, insertRes);
		Log.d(TAG, mInjectedName + " call json: " + reqJson + " result:" + resStr);
		return resStr;
	}
}