一、问题场景:
项目中遇到通过网页上传文件的需求,IOS直接是支持的,安卓端却没反应,有些机型甚至闪退。其实是Android的webview默认是不支持<input type="file"/>文件上传的。现在的前端页面需要处理的是:
1.打开本地文件选择器
2.用户选择需要上传的文件
3.处理用户选择的文件通知webview
4.前端提交表单上传文件
首先需要webview 对 JS 的支持,即 webview.getSettings().setJavaScriptEnable(true);其次要注意前端页面针对不同版本的android系统 webview内核会有不同,调用方法是不一样的。
二、问题解决:
1.需要授予的权限
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
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;
}
});
三、完整代码:
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:
1.最后我们在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。
2.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:
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);
}
(1)下图为 i.setType("*/*");
(2)下图为 i.setType("file/*");
四、引申其他一些设置
Android及iOS的webview的引擎都是webkit,对H5提供支持。
webview有两个方法:setWebChromeClient 和setWebClientsetWebClient
WebChromeClient:辅助WebView处理Javascript的对话框,网站图标,网站title,加载进度等
WebViewClient就是帮助WebView处理各种通知、请求事件的。
WebSetting常用方法总结:
1.setJavaScriptEnabled(true); //支持js
2.setPluginsEnabled(true); //支持插件
3.setUseWideViewPort(false); //将图片调整到适合webview的大小
4.setSupportZoom(true); //支持缩放
5.setLayoutAlgorithm(LayoutAlgorithm.SINGLE_COLUMN); //支持内容重新布
6.supportMultipleWindows(); //多窗口
7.setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK); //关闭webview中缓存
8.setAllowFileAccess(true); //设置可以访问文件
9.setNeedInitialFocus(true); //当webview调用requestFocus时为webview设置节点 webview
10. webSettings.setBuiltInZoomControls(true); //设置支持缩放
11.setJavaScriptCanOpenWindowsAutomatically(true); //支持通过JS打开新窗口
12.setLoadWithOverviewMode(true); // 缩放至屏幕的大小
13.setLoadsImagesAutomatically(true); //支持自动加载图片
部分内容参考了https://www.jianshu.com/p/fea5e829b30a,里面有更多的webview常见问题有空可以看看。