目前我正在开发android开发.根据要求,应用程序应该能够读取Excel文件以进行数据输入.
正如其他人从这个主题开始,我已经完成了Java Excel Api和Apache POI,但两者都需要进行一些修改以满足我的要求：
JExcel API：
– 不能支持XLSX
Apache POI：
– 支持XLS文件
– 要在Dalvik中支持XLSX,您需要克服64K和javax库,或使用端口版本(即从Andrew Kondratev开始)
– 文件大小将增加2.4MB
但是我们还有其他选择在Android 4或更低版本中使用Excel文件吗？
解决方法:
对于那些需要使用全功能excel文件(即绘图,VBA等等)的应用程序,你应该使用Apache POI,它很简单,但现在仍然是最好的解决方案.
但是,如果您只需要阅读Excel,那么使用JavaScript解决方案可能会更好.使用js-xlsx库,您可以将Excel文件传输到JSON.库大小很小,只有395KB(仅包括xlsx.core.min.js)
我相信这不是最好的解决方案：
– WebView需要使用UI Thread,它可能会在读取大型Excel文件时阻止UI.
– 性能问题
但您可以将其更改为其他JavaScript引擎(如Rhino或V8)以解决这些问题.
这是代码
回调接口：
public interface ExcelReaderListener {
void onReadExcelCompleted(List stringList);
}
主要活动：
private ProgressDialog progressDialog;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new AlertDialog.Builder(MainActivity.this)
.setMessage("message")
.setTitle("title")
.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
new FileChooser(MainActivity.this, new String[]{"xls", "xlsx"})
.setFileListener(new FileChooser.FileSelectedListener() {
@Override
public void fileSelected(File file) {
progressDialog = new ProgressDialog(MainActivity.this);
progressDialog.setTitle("title");
progressDialog.setMessage("message");
progressDialog.setIndeterminate(true);
progressDialog.setCanceledOnTouchOutside(false);
Toast.makeText(MainActivity.this, file.getName(), Toast.LENGTH_SHORT).show();
String filePath = file.getAbsolutePath();
ExcelReaderListener excelReaderListener = MainActivity.this;
progressDialog.show();
try {
final WebView webView = new WebView(MainActivity.this);
new JSExcelReader(filePath, webView, excelReaderListener);
} catch (Exception ex) {
Log.e("Import excel error", ex.getMessage());
}
}
})
.showDialog();
}
})
.show();
}
@Override
public void onReadExcelCompleted(List stringList) {
Toast.makeText(MainActivity.this, "Parse Completed", Toast.LENGTH_SHORT).show();
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
// Write into DB
...
}
用户选择excel文件的界面：
JSExcelReader :(读取excel并将其转换为ArrayList的核心部分)
public class JSExcelReader {
private ExcelReaderListener callback;
public JSExcelReader(String filePath, final WebView webView, ExcelReaderListener callback) {
this.callback = callback;
File file = new File(filePath);
try (InputStream is = new FileInputStream(file)) {
// convert file to Base64
if (file.length() > Integer.MAX_VALUE)
Log.e("File too big", "file too big");
byte[] bytes = new byte[(int) file.length()];
int offset = 0;
int numRead;
while (offset < bytes.length &&
(numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
offset += numRead;
}
if (offset < bytes.length)
throw new Exception("Could not completely read file");
final String b64 = Base64.encodeToString(bytes, Base64.NO_WRAP);
// feed the string into webview and get the result
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);
webView.loadUrl("file:///android_asset/AndroidParseExcel.html");
webView.setWebViewClient(new WebViewClient() {
public void onPageFinished(WebView view, String url) {
webView.evaluateJavascript("convertFile('" + b64 + "');", new ValueCallback() {
@Override
public void onReceiveValue(String value) {
parseJSON(value);
}
});
}
});
} catch (Exception ex) {
Log.e("Convert Excel failure", ex.getMessage());
}
}
private void parseJSON(String jsonString) {
try {
// return value is something like "{\n\"Sheet1\":\n[\"title\"...
// you need to remove those escape character first
JSONObject jsonRoot = new JSONObject(jsonString.substring(1, jsonString.length() - 1)
.replaceAll("\\\\n", "")
.replaceAll("\\\\\"", "\"")
.replaceAll("\\\\\\\\\"", "'"));
JSONArray sheet1 = jsonRoot.optJSONArray("Sheet1");
List stringList = new ArrayList<>();
JSONObject jsonObject;
for (int i = 0; i < sheet1.length(); i++) {
jsonObject = sheet1.getJSONObject(i);
stringList.add(jsonObject.optString("title"));
}
callback.onReadExcelCompleted(stringList);
} catch (Exception ex) {
Log.e("Error in parse JSON", ex.getMessage());
}
}
}
AndroidParseExcel.html :(你应该把这个和JavaScript库放到资产文件夹中)
"use strict";
var X = XLSX;
function convertFile(b64data) {
var wb = X.read(b64data, {type: 'base64',WTF: false});
var result = {};
wb.SheetNames.forEach(function(sheetName) {
var roa = X.utils.sheet_to_row_object_array(wb.Sheets[sheetName]);
if(roa.length > 0){
result[sheetName] = roa;
}
});
return JSON.stringify(result, 2, 2);
}
标签：jexcelapi,android,excel,apache-poi
来源： https://codeday.me/bug/20190727/1553770.html
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