Android WebView那些坑之上传文件示例

最近公司项目需要在WEBView上调用手机系统相册来上传图片，开发过程中发现在很多机器上无法正常唤起系统相册来选择图片。

解决问题之前我们先来说说WebView上传文件的逻辑：当我们在Web页面上点击选择文件的控件(<input type="file">)时，会回调WebChromeClient下的openFileChooser()（5.0及以上系统回调onShowFileChooser()）。这个时候我们在openFileChooser方法中通过Intent打开系统相册或者支持该Intent的第三方应用来选择图片。like this：

public void openFileChooser(ValueCallback<Uri> valueCallback, String acceptType, String capture) {
 uploadMessage = valueCallback;
  openImageChooserActivity();
}
private void openImageChooserActivity() {
 Intent i = new Intent(Intent.ACTioN_GET_CONTENT);
 i.addCateGory(Intent.CATEGORY_OPENABLE);
 i.setType("image
@Systemapi
@Deprecated
public void openFileChooser(ValueCallback<Uri> uploadFile, String acceptType, String capture) {
 uploadFile.onReceiveValue(null);
}

解决方案也很简单，直接不混淆openFileChooser()就好了。

-keepclaSSMembers class * extends Android.webkit.WebChromeClient{
  public void openFileChooser(...);
}

支持关于上传文件的所有坑都填完了，最后附上完整源码：

public class MainActivity extends AppCompatActivity {
 private ValueCallback<Uri> uploadMessage;
 private ValueCallback<Uri[]> uploadMessageAboveL;
 private final static int FILE_CHOOSER_RESULT_CODE = 10000;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  WebView webview = (WebView) findViewById(R.id.web_view);
  assert webview != null;
  WebSettings settings = webview.getSettings();
  settings.setUseWideViewPort(true);
  settings.setLoadWithOverviewMode(true);
  settings.setjavascriptEnabled(true);
  webview.setWebChromeClient(new WebChromeClient() {
   // For Android < 3.0
   public void openFileChooser(ValueCallback<Uri> valueCallback) {
    uploadMessage = valueCallback;
    openImageChooserActivity();
   }
   // For Android >= 3.0
   public void openFileChooser(ValueCallback valueCallback, String acceptType) {
    uploadMessage = valueCallback;
    openImageChooserActivity();
   }
   //For Android >= 4.1
   public void openFileChooser(ValueCallback<Uri> valueCallback, String acceptType, String capture) {
    uploadMessage = valueCallback;
    openImageChooserActivity();
   }
   // For Android >= 5.0
   @Override
   public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {
    uploadMessageAboveL = filePathCallback;
    openImageChooserActivity();
    return true;
   }
  });
  String targetUrl = "file:///android_asset/up.html";
  webview.loadUrl(targetUrl);
 }
 private void openImageChooserActivity() {
  Intent i = new Intent(Intent.ACTION_GET_CONTENT);
  i.addCategory(Intent.CATEGORY_OPENABLE);
  i.setType("image/*");
  startActivityForResult(Intent.createChooser(i, "Image Chooser"), FILE_CHOOSER_RESULT_CODE);
 }
 @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;
 }
}

源码地址: Http://xiazai.jb51.net/201701/yuanma/WebViewSample_jb51.rar

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