android WebView如何响应H5中读取文件的请求，唤起文件浏览界面

前言：

博主使用WebView展示了前端给我的H5页面，但是点击里面的选取图片按钮，没有反应，在微信的公众号浏览器中可以正常唤起文件浏览界面，于是上网找解决方案，按照以下方案在代码中进行了处理，问题得到了解决。

解决方案：

1.定义两个之后会用到的变量：

    private ValueCallback<Uri> mUploadMessage;
    private ValueCallback<Uri[]> mUploadCallbackAboveL;

2.webView变量调用setWebChromeClient方法设置一个client：

mWebView.setWebChromeClient(chromeClient);

3.定义chromeClient变量：

    WebChromeClient chromeClient = new WebChromeClient(){
        // For Android < 3.0
        public void openFileChooser(ValueCallback<Uri> valueCallback) {
            mUploadMessage = valueCallback;
            openImageChooserActivity();
        }

        // For Android  >= 3.0
        public void openFileChooser(ValueCallback valueCallback, String acceptType) {
            mUploadMessage = valueCallback;
            openImageChooserActivity();
        }

        //For Android  >= 4.1
        public void openFileChooser(ValueCallback<Uri> valueCallback, String acceptType, String capture) {
            mUploadMessage = valueCallback;
            openImageChooserActivity();
        }

        // For Android >= 5.0
        @Override
        public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {
            mUploadCallbackAboveL = filePathCallback;
            openImageChooserActivity();
            return true;
        }
    };

4.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/*");
        startActivityForResult(Intent.createChooser(i, "Image Chooser"), FILE_CHOOSER_RESULT_CODE);
    }

注：该方法在第3步中调用。

5.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 == mUploadMessage && null == mUploadCallbackAboveL) return;
            Uri result = data == null || resultCode != RESULT_OK ? null : data.getData();
            if (mUploadCallbackAboveL != null) {
                onActivityResultAboveL(requestCode, resultCode, data);
            } else if (mUploadMessage != null) {
                mUploadMessage.onReceiveValue(result);
                mUploadMessage = null;
            }
        }
    }

6.选择内容回调到H5页面：

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    private void onActivityResultAboveL(int requestCode, int resultCode, Intent intent) {
        if (requestCode != FILE_CHOOSER_RESULT_CODE || mUploadCallbackAboveL == 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)};
            }
        }
        mUploadCallbackAboveL.onReceiveValue(results);
        mUploadCallbackAboveL = null;
    }

OK，到这里就大功告成了。

使用过程中遇到问题给我留言，会尽快回复。

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