android使用WebView来打开文件选择器

最近了解了一下android的webview可以默认的调用系统的文件选择器。首先，网页的html写法要有<input type="file" ...>，这个在ios上也是可以默认调用系统的文件选择器，只不过可以选择部分文件，毕竟ios对文件的选择做了限制；

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今天主要来介绍一下，在android上要如何实现webview调用系统文件选择器，在网上一搜，是可以搜到许多，基本全都是要实现WebChromeClient的openFileChooser(…)，我就按网上的教程试了下，突然发现在有些手机上可行，有的则不可行，这就很奇怪了，为什么有的手机不行呢？让我百思不得其解，去网上搜索了好多资料也没有解决，后来翻看了一下源码后恍然大悟，原来5.0的WebChromeClient不是用的openFileChooser(…)，而是用的onShowFileChooser(…)，所以以后要特别注意下Google是否对Android的源码有改动。

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接下来就是如何实现的代码了:

public class BaseWebChromeClient extends WebChromeClient {

    public static final int FILECHOOSER_RESULTCODE = 10000;

    // For Android < 3.0
    public void openFileChooser(ValueCallback<Uri> uploadMsg) {

    }

    // For Android 3.0+
    public void openFileChooser(ValueCallback uploadMsg, String acceptType) {

    }

    //For Android 4.1
        public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {

    }
    //For Android 5.0+
    public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> valueCallback, FileChooserParams fileChooserParams) {
        return true;
    }

    public void onActivityResult(int resultCode, Intent data) {

    }
 }

class WebChromeClientAboveFive extends BaseWebChromeClient {

    private ValueCallback<Uri[]> mUploadCallbackAboveFive;
    private Activity mActivity;

    public WebChromeClientAboveFive(Activity activity) {
        this.mActivity = activity;
    }

    /**
     * 兼容5.0及以上
     *
     * @param webView
     * @param valueCallback
     * @param fileChooserParams
     * @return
     */
    @Override
    public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> valueCallback, android.webkit.WebChromeClient.FileChooserParams fileChooserParams) {
        mUploadCallbackAboveFive = valueCallback;
        Intent i = new Intent(Intent.ACTION_GET_CONTENT);
        i.addCategory(Intent.CATEGORY_OPENABLE);
        i.setType("*/*");
        mActivity.startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
        return true;
    }

    @Override
    public void onActivityResultInternal(int resultCode, Intent data) {
        if (null == mUploadCallbackAboveFive) {
            return;
        }
        Uri[] results = null;
        if (resultCode == Activity.RESULT_OK) {
            if (data != null) {
                String dataString = data.getDataString();
                ClipData clipData = data.getClipData();
                if (clipData != null) {
                    int itemCount = clipData.getItemCount();
                    results = new Uri[itemCount];
                    for (int i = 0; i < itemCount; i++) {
                        ClipData.Item item = clipData.getItemAt(i);
                        results[i] = item.getUri();
                    }
                }
                if (dataString != null) {
                    results = new Uri[]{Uri.parse(dataString)};
                }
            }
        }
        mUploadCallbackAboveFive.onReceiveValue(results);
        mUploadCallbackAboveFive = null;
        return;
    }
}

class DefaultWebChromeClient extends BaseWebChromeClient {

    private ValueCallback<Uri> mUploadMessage;
    private Activity mActivity;

    public DefaultWebChromeClient(Activity activity) {
        this.mActivity = activity;
    }

    // For Android < 3.0
    public void openFileChooser(ValueCallback<Uri> uploadMsg) {
        openFileChooser(mUploadMessage, "", "");
    }

    // For Android 3.0+
    public void openFileChooser(ValueCallback uploadMsg, String acceptType) {
        openFileChooser(mUploadMessage, acceptType, "");
    }

    //For Android 4.1
    public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
        mUploadMessage = uploadMsg;
        Intent i = new Intent(Intent.ACTION_GET_CONTENT);
        i.addCategory(Intent.CATEGORY_OPENABLE);
        i.setType("image/*");
        mActivity.startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
    }

    @Override
    public void onActivityResult(int resultCode, Intent data) {
        if (null == mUploadMessage) {
            return;
        }
        Uri result = data == null || resultCode != Activity.RESULT_OK ? null
                : data.getData();
        if (mUploadMessage != null) {
            mUploadMessage.onReceiveValue(result);
            mUploadMessage = null;
        }
    }
}

分别写了2个类来处理不同版本的，在Activity的onActivityResult()回调中，可以调用相应webChromeClient的onActivityResult()的方法