混合开发--查找文件插件开发

package 包名;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

import org.json.JSONArray;
import org.json.JSONException;

import android.app.Activity;
import android.os.Environment;
import android.util.Log;
import io.dcloud.common.DHInterface.IWebview;
import io.dcloud.common.DHInterface.StandardFeature;
import io.dcloud.common.util.JSUtil;

public class Check_File_Exist extends StandardFeature {
	Activity activity;
	String checkFileCallbackID;
	IWebview webview;

	// 页面传递参数(带后缀)
	String filename = "";

	@SuppressWarnings("unused")
	public void checkFile(IWebview pWebview, JSONArray array) {
		Log.i("checkFile--->", "成功进入检查文件插件");
		activity = pWebview.getActivity();
		checkFileCallbackID = array.optString(0);
		webview = pWebview;
		JSUtil.execCallback(webview, checkFileCallbackID, "ENTER_CHECK_FILE_CHAJIAN", JSUtil.OK, true);
		JSONArray jsonArray = null;
		try {
			jsonArray = new JSONArray(array.optString(1));
			filename = jsonArray.getString(0);
			Log.i("filename-->", filename);
			// 进行文件是否存在下载文件下的判断
			if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
				// 获取sdcard的读写成功
				JSUtil.execCallback(webview, checkFileCallbackID, "GET_SDCARD_SUCCESS", JSUtil.OK, true);
				// /storage/emulated/0
				String path1 = Environment.getExternalStorageDirectory().toString();
				// /data
				String path2 = Environment.getDataDirectory().toString();
				// 项目包名
				String path3 = activity.getApplicationContext().getPackageName();
				// /storage/emulated/0/Android/data/项目包名/downloads/文件名
				String allPath = path1+"/Android" + path2 + "/" +path3 + "/downloads/" + filename;
				Log.i("checkFile--当前拼接路径-->", allPath);
				File files = new File(allPath);
				
				//方法一   使用流去读大小
				/*InputStream inputStream = null;
				try {
					inputStream = new FileInputStream(files);
					int fileSize = inputStream.available();
					JSUtil.execCallback(webview, checkFileCallbackID, "EXIST_FILE", JSUtil.OK, true);
				} catch (FileNotFoundException e) {
					// 未找到文件
					JSUtil.execCallback(webview, checkFileCallbackID, "NOT_EXIST_FILE", JSUtil.OK, true);
					e.printStackTrace();
				} catch (IOException e) {
					// 异常
					JSUtil.execCallback(webview, checkFileCallbackID, "IO_EXCEPTION", JSUtil.OK, true);
					e.printStackTrace();
				}*/
				
				//方法二   通过file判断
				if(files.exists() && !files.isDirectory()) {
					Log.i("checkFile-->", "文件存在且不为文件夹");
					JSUtil.execCallback(webview, checkFileCallbackID, "EXIST_FILE", JSUtil.OK, true);
				}else {
					Log.i("checkFile-->", "文件不存在或格式为文件夹");
					JSUtil.execCallback(webview, checkFileCallbackID, "NOT_EXIST_FILE", JSUtil.OK, true);
				}

			} else {
				JSUtil.execCallback(webview, checkFileCallbackID, "GET_SDCARD_FAIL", JSUtil.OK, true);
			}

		} catch (JSONException e) {
			// 传输数据格式异常
			JSUtil.execCallback(webview, checkFileCallbackID, "JSON_EXCEPTION", JSUtil.OK, true);
			e.printStackTrace();
		}
	}
}

查找指定文件夹下是否存在指定的文件名称(APP中根据安装后的地址再查询)