Android,无法使用WebView上传图片

Question

我正在为我的问题寻找解决方案,但我找不到一个好的解决方案.所以我想在开始为Android开发本机应用程序之前再问一遍,因为我无法解决这个问题.

正如标题所说,我正在尝试使用webview将图像上传到html内容,而NORMALLY正在选择图像,在页面上显示它并允许用户裁剪它.我制作了完整的应用程序,并在我的手机的普通浏览器上进行了测试,所以我不知道这不起作用.这就是为什么它令人沮丧.

我在互联网上找到的那些解决方案对我的Android不起作用,我读到它已经不可能了.

有谁知道这是否可能？如果我能得到更多关于此的信息(即使它可能与否,这将是一个很大的帮助？)感谢Adavnce ...

Answer 1

尝试添加这些权限。

<uses-permission android:name="android.permission.INTERNET" /> 
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> 
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Android 6.0 Marshmallow引入了一种新的权限处理模型，可简化用户安装和升级应用程序时的流程。如果您使用的是8.1版或更高版本的Google Play服务，则可以将您的应用配置为以Android 6.0 Marshmallow SDK为目标并使用新的权限模型。

如果您的应用程序支持新的权限模型，则用户在安装或升级应用程序时不必授予任何权限。相反，应用程序必须在运行时需要权限时才请求权限，并且系统向用户显示一个对话框，询问权限。

要了解更多信息，请参阅Android 6.0 Marshmallow文档以及必须为新权限模型对应用程序进行的更改。

Google已添加WebChromeClient.onShowFileChooser。它们甚至提供了一种自动生成文件选择器意图的方法，以便它使用输入的接受mime类型。

以这种方式实现（来自weiyin的回答）：

public class MyWebChromeClient extends WebChromeClient {
        // reference to activity instance. May be unnecessary if your web chrome client is member class.
    private MyActivity myActivity;

    public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, FileChooserParams fileChooserParams) {
        // make sure there is no existing message
        if (myActivity.uploadMessage != null) {
            myActivity.uploadMessage.onReceiveValue(null);
            myActivity.uploadMessage = null;
        }

        myActivity.uploadMessage = filePathCallback;

        Intent intent = fileChooserParams.createIntent();
        try {
            myActivity.startActivityForResult(intent, MyActivity.REQUEST_SELECT_FILE);
        } catch (ActivityNotFoundException e) {
            myActivity.uploadMessage = null;
            Toast.makeText(myActivity, "Cannot open file chooser", Toast.LENGTH_LONG).show();
            return false;
        }

        return true;
    }
}


public class MyActivity extends ... {
    public static final int REQUEST_SELECT_FILE = 100;
    public ValueCallback<Uri[]> uploadMessage;

    protected void onActivityResult(int requestCode, int resultCode, Intent data){
        if (requestCode == REQUEST_SELECT_FILE) {
                if (uploadMessage == null) return;
                uploadMessage.onReceiveValue(WebChromeClient.FileChooserParams.parseResult(resultCode, data));
                uploadMessage = null;
            }
        }
    }
}

确保使用API​​ 21+编译应用程序。正如您提到的那样，这将在所有平台上都有效。

Answer 2

这是从 API 11 到 23 的工作方法

static WebView mWebView;
private ValueCallback<Uri> mUploadMessage;
public ValueCallback<Uri[]> uploadMessage;
public static final int REQUEST_SELECT_FILE = 100;
private final static int FILECHOOSER_RESULTCODE = 1;

现在修改或覆盖您的 onActivityResult 方法

@Override
public void onActivityResult(int requestCode, int resultCode, Intent intent)
{
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
    {
        if (requestCode == REQUEST_SELECT_FILE)
        {
            if (uploadMessage == null)
                return;
                uploadMessage.onReceiveValue(WebChromeClient.FileChooserParams.parseResult(resultCode, intent));
        uploadMessage = null;
    }
}
else if (requestCode == FILECHOOSER_RESULTCODE)
{
    if (null == mUploadMessage)
        return;
// Use MainActivity.RESULT_OK if you're implementing WebView inside Fragment
// Use RESULT_OK only if you're implementing WebView inside an Activity
    Uri result = intent == null || resultCode != MainActivity.RESULT_OK ? null : intent.getData();
    mUploadMessage.onReceiveValue(result);
    mUploadMessage = null;
}
else
    Toast.makeText(getActivity().getApplicationContext(), "Failed to Upload Image", Toast.LENGTH_LONG).show();
}

现在在 onCreate 方法中粘贴以下代码

mWebView.setWebChromeClient(new WebChromeClient()
{
// For 3.0+ Devices (Start)
// onActivityResult attached before constructor
protected void openFileChooser(ValueCallback uploadMsg, String acceptType)
{
    mUploadMessage = uploadMsg;
    Intent i = new Intent(Intent.ACTION_GET_CONTENT);
    i.addCategory(Intent.CATEGORY_OPENABLE);
    i.setType("image/*");
    startActivityForResult(Intent.createChooser(i, "File Browser"), FILECHOOSER_RESULTCODE);
}


// For Lollipop 5.0+ Devices
public boolean onShowFileChooser(WebView mWebView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams)
{
    if (uploadMessage != null) {
        uploadMessage.onReceiveValue(null);
        uploadMessage = null;
    }

    uploadMessage = filePathCallback;

    Intent intent = fileChooserParams.createIntent();
    try
    {
        startActivityForResult(intent, REQUEST_SELECT_FILE);
    } catch (ActivityNotFoundException e)
    {
        uploadMessage = null;
        Toast.makeText(getActivity().getApplicationContext(), "Cannot Open File Chooser", Toast.LENGTH_LONG).show();
        return false;
    }
    return true;
}

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

protected void openFileChooser(ValueCallback<Uri> uploadMsg)
{
    mUploadMessage = uploadMsg;
    Intent i = new Intent(Intent.ACTION_GET_CONTENT);
    i.addCategory(Intent.CATEGORY_OPENABLE);
    i.setType("image/*");
    startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
}
});