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// 搜索文件的异步任务                  		                new AsyncTask
   
    () {  		                      		                    private ProgressDialog dialog;  		  		                    // UI显示  		                    protected void onPreExecute() {  		                        Log.i(TAG, "onPreExecute Thread id "+Thread.currentThread().getId());  		                        dialog = ProgressDialog.show(  		                        		context, "",  		                                "正在扫描SD卡,请稍候....");  		                        super.onPreExecute();  		                    }  		  		                    // 后台执行  		                    protected String doInBackground(Integer... params) {  		                        Log.i(TAG, "doInBackground Thread id "+Thread.currentThread().getId());  		                        if (!android.os.Environment.getExternalStorageState()  		                                .equals(android.os.Environment.MEDIA_MOUNTED)) {  		  		                        } else {  		                            if (!editText.getText().toString().equals("")) {  		                                filelist.clear();  		                                return Search_Files(Environment  		                                        .getExternalStorageDirectory());  		                            }  		                        }  		                        return null;  		                    }  		  		                    // 搜索完毕后，结果处理  		                    protected void onPostExecute(String result) {  		                        Log.i(TAG, "onPostExecute Thread id "+Thread.currentThread().getId());  		                        dialog.dismiss();  		                        if (editText.getText().toString().equals("")) {  		                            Toast.makeText(context,  		                                    "请输入搜索的文件名", 1000).show();  		                        } else {  		                             new AlertDialog.Builder(context)  		                             .setTitle("SD卡搜索结果")  		                             .setMessage(result)  		                             .create().show();                            		                        }  		                        super.onPostExecute(result);  		                    }  		                }.execute(0);
   

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