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WebView系列之——读取本地文件

程序员文章站 2024-01-16 19:11:04
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WebView读取本地文件前提条件

当加载的网页中存在 <input type="file"> 时，点击按钮需要读取本地文件。

需要添加读取权限<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

WebView系列之——读取本地文件

原生中存在的问题

  1. 5.0 以前不存选择文件的公开API,只存在@hide的api
  2. 5.0 以后可已在WebChromeClient中重写onShowFileChooser
  3. 4.4 中不存在任何关于选择文件的api，连@hide的也没有—4.不支持选取文件(只能通过注入js的方式)

解决方案:

1.在WebChromeClient中添加对应方法：

// For Android < 3.0
public void openFileChooser(ValueCallback<Uri> valueCallback) {
    uploadMessage = valueCallback;
    openFileChooserActivity();
}

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

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

// For Android >= 5.0
@Override
public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {
    uploadMessageAboveL = filePathCallback;
    openFileChooserActivity();
    return true;
}
如果有混淆处理，需要取消对openFileChooser的混淆

因为这个方法是@hide的，所以编译的SDK中没有，如果不做混淆处理，会将此方法混淆。

-keepclassmembers class * extends android.webkit.WebChromeClient{
public void openFileChooser(...);
}

2.在Activity中调起本地选择器

private void openFileChooserActivity() {
    Intent i = new Intent(Intent.ACTION_GET_CONTENT);
    i.addCategory(Intent.CATEGORY_OPENABLE);
    i.setType("*/*");
    //判断设备中是否存在处理当前intent的app
    if (i.resolveActivity(getPackageManager()) != null) {
    startActivityForResult(Intent.createChooser(i, "File Chooser"), FILE_CHOOSER_RESULT_CODE);
    }
}

3.接受返回数据并回调给WebVIew

@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();
        if (uploadMessageAboveL != null) {
            onActivityResultAboveL(requestCode, resultCode, data);
        } else if (uploadMessage != null) {
            uploadMessage.onReceiveValue(result);
            uploadMessage = null;
    }
}
}

@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;
}

完整源码

public class LoadFileFromLocalActivity extends AppCompatActivity {

    WebView webView;
    private ValueCallback<Uri> uploadMessage;
    private ValueCallback<Uri[]> uploadMessageAboveL;
    private final static int FILE_CHOOSER_RESULT_CODE = 10000;


    public static final String html = "<!DOCTYPE html>\n" +
    "<html lang=\"en\">\n" +
    "<head>\n" +
    " <meta charset=\"UTF-8\">\n" +
    " <title>Title</title>\n" +
    "</head>\n" +
    "<input type=\"file\">\n" +
    "</body>\n" +
    "</html>";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_load_file_from_local);
        webView = findViewById(R.id.webView);
        WebSettings settings = webView.getSettings();
        settings.setUseWideViewPort(true);
        settings.setLoadWithOverviewMode(true);
        settings.setJavaScriptEnabled(true);
        webView.setWebChromeClient(new MyChromeClient());
        webView.loadData(html, "text/html", "utf-8");

    }
    public class MyChromeClient extends WebChromeClient {
    // For Android < 3.0
    public void openFileChooser(ValueCallback<Uri> valueCallback) {
        uploadMessage = valueCallback;
        openFileChooserActivity();
    }

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

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

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

    private void openImageChooserActivity() {
        Intent i = new Intent(Intent.ACTION_GET_CONTENT);
        i.addCategory(Intent.CATEGORY_OPENABLE);
        i.setType("*/*");
        if (i.resolveActivity(getPackageManager()) != null) {
            startActivityForResult(Intent.createChooser(i, "Image Chooser"), FILE_CHOOSER_RESULT_CODE);
        }
    }

    /*
    # 需要混淆
    -keepclassmembers class * extends android.webkit.WebChromeClient{
    public void openFileChooser(...);
    }
    */

    /**
    * 需要的权限 android.permission.READ_EXTERNAL_STORAGE
    * @param requestCode
    * @param resultCode
    * @param data
    */
    @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();
            if (uploadMessageAboveL != null) {
                onActivityResultAboveL(requestCode, resultCode, data);
            } else if (uploadMessage != null) {
                uploadMessage.onReceiveValue(result);
                uploadMessage = null;
            }
        }
    }

    @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;
    }
    // life circles ----------------------------------
    @Override
    protected void onResume() {
        super.onResume();
        webView.onResume();
    }

    @Override
    protected void onPause() {
        webView.onPause();
        super.onPause();
    }

    @Override
    protected void onDestroy() {
    webView.destroy();
    super.onDestroy();
    }
}
相关标签： WebView 读取本地文件 Android

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