WebView系列之——讀取本地檔案
阿新 • • 發佈：2019-01-28
WebView讀取本地檔案前提條件
當載入的網頁中存在 <input type="file"> 時，點選按鈕需要讀取本地檔案。
需要新增讀取許可權<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
原生中存在的問題
- 5.0 以前不存選擇檔案的公開API,只存在
@hide的api - 5.0 以後可已在WebChromeClient中重寫
onShowFileChooser - 4.4 中不存在任何關於選擇檔案的api，連
@hide的也沒有—4.不支援選取檔案(只能通過注入js的方式)
解決方案:
1.在WebChromeClient中新增對應方法：
// For Android < 3.0
public void openFileChooser(ValueCallback<Uri> valueCallback) {
uploadMessage = valueCallback;
openFileChooserActivity();
}
// For Android >= 3.0
public void openFileChooser(ValueCallback valueCallback, String acceptType) {
uploadMessage = valueCallback;
openFileChooserActivity();
}
//For Android >= 4.1 如果有混淆處理，需要取消對openFileChooser的混淆
因為這個方法是@hide的，所以編譯的SDK中沒有，如果不做混淆處理，會將此方法混淆。
-keepclassmembers class * extends android.webkit.WebChromeClient{
public void openFileChooser(...);
}2.在Activity中調起本地選擇器
private void openFileChooserActivity() {
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
i.setType("*/*");
//判斷裝置中是否存在處理當前intent的app
if (i.resolveActivity(getPackageManager()) != null) {
startActivityForResult(Intent.createChooser(i, "File Chooser"), FILE_CHOOSER_RESULT_CODE);
}
}3.接受返回資料並回調給WebVIew
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == FILE_CHOOSER_RESULT_CODE) {
if (null == uploadMessage && null == uploadMessageAboveL) return;
Uri result = data == null || resultCode != RESULT_OK ? null : data.getData();
if (uploadMessageAboveL != null) {
onActivityResultAboveL(requestCode, resultCode, data);
} else if (uploadMessage != null) {
uploadMessage.onReceiveValue(result);
uploadMessage = null;
}
}
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
private void onActivityResultAboveL(int requestCode, int resultCode, Intent intent) {
if (requestCode != FILE_CHOOSER_RESULT_CODE || uploadMessageAboveL == null) {
return;
}
Uri[] results = null;
if (resultCode == Activity.RESULT_OK) {
if (intent != null) {
String dataString = intent.getDataString();
ClipData clipData = intent.getClipData();
if (clipData != null) {
results = new Uri[clipData.getItemCount()];
for (int i = 0; i < clipData.getItemCount(); i++) {
ClipData.Item item = clipData.getItemAt(i);
results[i] = item.getUri();
}
}
if (dataString != null) {
results = new Uri[]{Uri.parse(dataString)};
}
}
}
uploadMessageAboveL.onReceiveValue(results);
uploadMessageAboveL = null;
}完整原始碼
public class LoadFileFromLocalActivity extends AppCompatActivity {
WebView webView;
private ValueCallback<Uri> uploadMessage;
private ValueCallback<Uri[]> uploadMessageAboveL;
private final static int FILE_CHOOSER_RESULT_CODE = 10000;
public static final String html = "<!DOCTYPE html>\n" +
"<html lang=\"en\">\n" +
"<head>\n" +
" <meta charset=\"UTF-8\">\n" +
" <title>Title</title>\n" +
"</head>\n" +
"<input type=\"file\">\n" +
"</body>\n" +
"</html>";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_load_file_from_local);
webView = findViewById(R.id.webView);
WebSettings settings = webView.getSettings();
settings.setUseWideViewPort(true);
settings.setLoadWithOverviewMode(true);
settings.setJavaScriptEnabled(true);
webView.setWebChromeClient(new MyChromeClient());
webView.loadData(html, "text/html", "utf-8");
}
public class MyChromeClient extends WebChromeClient {
// For Android < 3.0
public void openFileChooser(ValueCallback<Uri> valueCallback) {
uploadMessage = valueCallback;
openFileChooserActivity();
}
// For Android >= 3.0
public void openFileChooser(ValueCallback valueCallback, String acceptType) {
uploadMessage = valueCallback;
openFileChooserActivity();
}
//For Android >= 4.1
public void openFileChooser(ValueCallback<Uri> valueCallback, String acceptType, String capture) {
uploadMessage = valueCallback;
openFileChooserActivity();
}
// For Android >= 5.0
@Override
public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {
uploadMessageAboveL = filePathCallback;
openFileChooserActivity();
return true;
}
}
private void openImageChooserActivity() {
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
i.setType("*/*");
if (i.resolveActivity(getPackageManager()) != null) {
startActivityForResult(Intent.createChooser(i, "Image Chooser"), FILE_CHOOSER_RESULT_CODE);
}
}
/*
# 需要混淆
-keepclassmembers class * extends android.webkit.WebChromeClient{
public void openFileChooser(...);
}
*/
/**
* 需要的許可權 android.permission.READ_EXTERNAL_STORAGE
* @param requestCode
* @param resultCode
* @param data
*/
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == FILE_CHOOSER_RESULT_CODE) {
if (null == uploadMessage && null == uploadMessageAboveL) return;
Uri result = data == null || resultCode != RESULT_OK ? null : data.getData();
if (uploadMessageAboveL != null) {
onActivityResultAboveL(requestCode, resultCode, data);
} else if (uploadMessage != null) {
uploadMessage.onReceiveValue(result);
uploadMessage = null;
}
}
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
private void onActivityResultAboveL(int requestCode, int resultCode, Intent intent) {
if (requestCode != FILE_CHOOSER_RESULT_CODE || uploadMessageAboveL == null) {
return;
}
Uri[] results = null;
if (resultCode == Activity.RESULT_OK) {
if (intent != null) {
String dataString = intent.getDataString();
ClipData clipData = intent.getClipData();
if (clipData != null) {
results = new Uri[clipData.getItemCount()];
for (int i = 0; i < clipData.getItemCount(); i++) {
ClipData.Item item = clipData.getItemAt(i);
results[i] = item.getUri();
}
}
if (dataString != null) {
results = new Uri[]{Uri.parse(dataString)};
}
}
}
uploadMessageAboveL.onReceiveValue(results);
uploadMessageAboveL = null;
}
// life circles ----------------------------------
@Override
protected void onResume() {
super.onResume();
webView.onResume();
}
@Override
protected void onPause() {
webView.onPause();
super.onPause();
}
@Override
protected void onDestroy() {
webView.destroy();
super.onDestroy();
}
}