问题场景
这几天在写一个 app 项目的时候,项目内置本地的 H5,H5 内使用了 layui 框架内的上传图片的操作,这个操作在 PC 的 Google Chrome 浏览器的移动模拟 H5 页面中没有问题,在手机中的自带浏览器中也没有问题,但在 app 的 webView 中始终没有作用(反应)。
看下 JS layui 部分的代码:
// 图片上传
layui.use(['upload', 'layer'], function () {
var upload = layui.upload;
var layer = layui.layer;
var index;
upload.render({
elem: '#up-image'
, accept: 'images'
, exts: 'jpg|jpeg|png|gif'
, url: '/upload'
, before: function () {
……
}
, done: function (res) {
……
}
, error: function () {
// 请求异常回调
}
});
});
出现问题后,首先需要webview 对 JS 的支持,即: setJavaScriptEnable (具体的设置本站中有记录,可看这里),可检查了一遍项目代码发现有这项的设置代码。于是呼又沉静在找到问题的原因与解决方法中,找了半天时间,终于找到问题的原因与解决方法。
问题的原因
Android 的 webView 默认是不支持文件上传的。即:
<input type="file"/>
解决的方法
1、需要授予的权限 READ_EXTERNAL_STORAGE 权限添加方式可看【Android permission 访问权限大全】
2、针对不同系统的处理
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;
}
});
3、完整的示例代码
package com.wwy.test.webview_takepicture_upload_demo;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.ClipData;
import android.content.Intent;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import com.wwy.mytest.webview_takepicture_upload_demo.R;
public class WebViewActivity 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_web_view);
WebView webview = (WebView) findViewById(R.id.web_view);
WebSettings settings = webview.getSettings();
settings.setUseWideViewPort(true);
settings.setLoadWithOverviewMode(true);
settings.setJavaScriptEnabled(true);
// 1.设置WebChromeClient,重写文件上传回调
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;
}
});
//加载本地网页
String targetUrl = "file:///android_asset/takePicture-upload/index.html";
webview.loadUrl(targetUrl);
}
// 2.回调方法触发本地选择文件
private void openImageChooserActivity() {
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
// i.setType("image/*");//图片上传
// i.setType("file/*");//文件上传
i.setType("*/*");//文件上传
startActivityForResult(Intent.createChooser(i, "Image Chooser"), FILE_CHOOSER_RESULT_CODE);
}
// 3.选择图片后处理
@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();
// 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;
}
} else {
//这里uploadMessage跟uploadMessageAboveL在不同系统版本下分别持有了
//WebView对象,在用户取消文件选择器的情况下,需给onReceiveValue传null返回值
//否则WebView在未收到返回值的情况下,无法进行任何操作,文件选择器会失效
if (uploadMessage != null) {
uploadMessage.onReceiveValue(null);
uploadMessage = null;
} else if (uploadMessageAboveL != null) {
uploadMessageAboveL.onReceiveValue(null);
uploadMessageAboveL = null;
}
}
}
// 4. 选择内容回调到Html页面
@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;
}
}
注意:
- 在 Acitivity 的 onActivityResult() 方法中处理,不管请求是否成功,我们都要在onReceiveValue()传null,否则html中的js执行一次就不会再执行,即我们点击不会在有响应了。
- openImageChooserActivity 这个方法里可以选择上传的文件类型,可以限制为图片或者从文件夹中选择图片上传
转载请注明:隨習筆記 » webView支持H5页面通过js实现文件上传、图片上传