android项目从零开始 Android webview支持 文件上传、图片上传

项目中用webview包裹网站，出现上传文件无反应的情况，之前了解过文件上传。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

webview.getSettings().setJavaScriptEnable(true)

前端页面针对不同版本的android系统 webview内核会有不同，调用方法不一致

webview.setWebChromeClient(new WebChromeClient() {

        // For Android < 3.0
        public void openFileChooser(ValueCallback<Uri> valueCallback) {
            ***
        }

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

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

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

完整代码

public class MainActivity 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_main);

        WebView webview = (WebView) findViewById(R.id.web_view);
        assert webview != null;
        WebSettings settings = webview.getSettings();
        settings.setUseWideViewPort(true);
        settings.setLoadWithOverviewMode(true);
        settings.setJavaScriptEnabled(true);
        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;
            }
        });
        String targetUrl = "file:///android_asset/up.html";
        webview.loadUrl(targetUrl);
    }

    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);
    }

    @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;
    }
}