JS调用Android摄像头拍照
产品经理要求H5要实现直接调用原生摄像头完成拍照功能：
一开始也是糊涂，我们前端的哥们总说用JS可以直接调用，不用Android的Java代码，所以我一开始也信了，想了想不是那么回事，可以调用也是通过原生封装好的。
下面写代码。先上JS的
说明：
- JS含有和Android的交互，调用摄像头的方法和接收Android传递过来的照片信息
2.对照片信息的处理(Base64的处理)（JS是自己写的，H5写的有点low见谅）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<hr>
<hr>
<hr>
<button type="button" style="width: 500px;height: 200px;" id="btn1" onclick="btnOnclick()">拍照
</button>
<hr>
<hr>
<!--<img src="" id="img_id">-->
<img src="http://www.runoob.com/wp-content/uploads/2013/07/pic_html5.gif" id="img_id">
</body>
<script>
var receiveBase64StrData = function (json) {
//①接收到Android传递过来的json信息
var base64Str = json.base64EncodeImgStr;
var base64 = new Base64();
var onject = base64.decode(base64Str);
onject = onject.replace(/[\r\n]/g, "");
document.getElementById("img_id").src = "data:image/jpeg;base64," + onject;
};
btnOnclick = function () {
window.jsInterface.takePhoto();
};
//1.加密解密方法使用：
//1.加密
//var str = '124中文内容';
var base = new Base64();
//var result = base.encode(str);
//document.write(result);
//2.解密
var result2 = base.decode(result);
document.write(result2);
//2.加密、解密算法封装：
function Base64() {
// private property
_keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
// public method for encoding
this.encode = function (input) {
var output = "";
var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
var i = 0;
input = _utf8_encode(input);
while (i < input.length) {
chr1 = input.charCodeAt(i++);
chr2 = input.charCodeAt(i++);
chr3 = input.charCodeAt(i++);
enc1 = chr1 >> 2;
enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
enc4 = chr3 & 63;
if (isNaN(chr2)) {
enc3 = enc4 = 64;
} else if (isNaN(chr3)) {
enc4 = 64;
}
output = output +
_keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
_keyStr.charAt(enc3) + _keyStr.charAt(enc4);
}
return output;
}
// public method for decoding
this.decode = function (input) {
var output = "";
var chr1, chr2, chr3;
var enc1, enc2, enc3, enc4;
var i = 0;
input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
while (i < input.length) {
enc1 = _keyStr.indexOf(input.charAt(i++));
enc2 = _keyStr.indexOf(input.charAt(i++));
enc3 = _keyStr.indexOf(input.charAt(i++));
enc4 = _keyStr.indexOf(input.charAt(i++));
chr1 = (enc1 << 2) | (enc2 >> 4);
chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
chr3 = ((enc3 & 3) << 6) | enc4;
output = output + String.fromCharCode(chr1);
if (enc3 != 64) {
output = output + String.fromCharCode(chr2);
}
if (enc4 != 64) {
output = output + String.fromCharCode(chr3);
}
}
output = _utf8_decode(output);
return output;
};
// private method for UTF-8 encoding
_utf8_encode = function (string) {
string = string.replace(/\r\n/g, "\n");
var utftext = "";
for (var n = 0; n < string.length; n++) {
var c = string.charCodeAt(n);
if (c < 128) {
utftext += String.fromCharCode(c);
} else if ((c > 127) && (c < 2048)) {
utftext += String.fromCharCode((c >> 6) | 192);
utftext += String.fromCharCode((c & 63) | 128);
} else {
utftext += String.fromCharCode((c >> 12) | 224);
utftext += String.fromCharCode(((c >> 6) & 63) | 128);
utftext += String.fromCharCode((c & 63) | 128);
}
}
return utftext;
}
// private method for UTF-8 decoding
_utf8_decode = function (utftext) {
var string = "";
var i = 0;
var c = c1 = c2 = 0;
while (i < utftext.length) {
c = utftext.charCodeAt(i);
if (c < 128) {
string += String.fromCharCode(c);
i++;
} else if ((c > 191) && (c < 224)) {
c2 = utftext.charCodeAt(i + 1);
string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
i += 2;
} else {
c2 = utftext.charCodeAt(i + 1);
c3 = utftext.charCodeAt(i + 2);
string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
i += 3;
}
}
return string;
}
}
</script>
</html>
下面是Android端的代码
说明：
1.含有拍照逻辑
2.对照片的处理，加密和处理旋转问题(三星拍照的照片被旋转，其他不知道)
3.照片的bitmap太大的话需要处理压缩，以免出现OOM，这样JS端会显示不出来，这里只是简单的处理了一下，有需要的话根据需要去动态处理。
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private WebView webView;
private JavaScriptMethods mJsMethods;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
webView = (WebView) findViewById(R.id.webview);
initWebView();
}
private void initWebView() {
WebSettings settings = webView.getSettings();
settings.setJavaScriptEnabled(true);
// 支持缩放
initListener();
mJsMethods = new JavaScriptMethods(MainActivity.this, this, webView);
webView.addJavascriptInterface(mJsMethods, JavaScriptMethods.JSINTERFACE);
webView.loadUrl("file:///android_asset/H5.html");
}
private void initListener() {
webView.setWebChromeClient(new WebChromeClient() {
@Override
public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
return super.onJsAlert(view, url, message, result);
}
@Override
public void onProgressChanged(WebView view, final int newProgress) {
super.onProgressChanged(view, newProgress);
}
@Override
public void onReceivedTitle(WebView view, String title) {
super.onReceivedTitle(view, title);
}
});
webView.setWebViewClient(new WebViewClient() {
@Nullable
@Override
public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
return super.shouldInterceptRequest(view, request);
}
@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
super.onReceivedError(view, errorCode, description, failingUrl);
//6.0以下
}
@RequiresApi(api = Build.VERSION_CODES.M)
@Override
public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
super.onReceivedError(view, request, error);
}
@Override
public void onReceivedHttpError(WebView view, WebResourceRequest request, WebResourceResponse errorResponse) {
super.onReceivedHttpError(view, request, errorResponse);
}
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
}
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && requestCode == JavaScriptMethods.TAKE_PHOTO) {
Log.d(TAG, "拍到图片");
//保存照片显示在H5界面
//获取照片的旋转角度，三星的拍照后旋转了90度
int bitmapDegree = getBitmapDegree(mJsMethods.filePath);
Log.d("照片的旋转:", "" + bitmapDegree);
Uri uri = Uri.fromFile(new File(mJsMethods.filePath));
try {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.RGB_565;
//参数可调，值越大图片大小越小
options.inSampleSize = 4;
Bitmap takePhotoBitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri), null, options);
//纠正旋转角度
Bitmap rotateBitmapByDegreebitmap = rotateBitmapByDegree(takePhotoBitmap, bitmapDegree);
//转64并加密，加密是因为给H5 传递json的时候会有回车换行，加密后消除，但是要在H5端做解密操作，
// 并除去回车换行符，在Android端做也是一样的
String base64ImgStr = Base64Util.bitmapToBase64(rotateBitmapByDegreebitmap);
String base64EncodeImgStr = Base64Util.encode(base64ImgStr);
JSONObject json = new JSONObject();
json.put("base64EncodeImgStr", base64EncodeImgStr);
String url = "javascript:receiveBase64StrData(" + json.toString() + ")";
webView.loadUrl(url);
takePhotoBitmap.recycle();
rotateBitmapByDegreebitmap.recycle();
} catch (FileNotFoundException | JSONException e) {
e.printStackTrace();
}
}
}
/**
* 读取图片的旋转的角度
*
* @param path 图片绝对路径
* @return 图片的旋转角度
*/
private int getBitmapDegree(String path) {
int degree = 0;
try {
// 从指定路径下读取图片，并获取其EXIF信息
ExifInterface exifInterface = new ExifInterface(path);
// 获取图片的旋转信息
int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_NORMAL);
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_90:
degree = 90;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
degree = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_270:
degree = 270;
break;
default:
break;
}
} catch (IOException e) {
e.printStackTrace();
}
return degree;
}
/**
* 将图片按照某个角度进行旋转
*
* @param bm 需要旋转的图片
* @param degree 旋转角度
* @return 旋转后的图片
*/
public Bitmap rotateBitmapByDegree(Bitmap bm, int degree) {
Bitmap returnBm = null;
// 根据旋转角度，生成旋转矩阵
Matrix matrix = new Matrix();
matrix.postRotate(degree);
try {
// 将原始图片按照旋转矩阵进行旋转，并得到新的图片
returnBm = Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(), matrix, true);
} catch (OutOfMemoryError e) {
Log.d("内存溢出", "");
}
if (returnBm == null) {
returnBm = bm;
}
if (bm != returnBm) {
bm.recycle();
}
return returnBm;
}
}
JS和Android的桥梁搭建
这里就不多说了不会调用的去百度，网上很多。
/**
* JS和Android互调的桥梁
*/
public class JavaScriptMethods {
public static String JSINTERFACE = "jsInterface";
private Activity mActivity;
private WebView mWebView;
private Context mContext;
public static final int TAKE_PHOTO = 1000;
public JavaScriptMethods(Activity activity, Context context, WebView webView) {
mActivity = activity;
mWebView = webView;
mContext = context;
}
public String filePath = Environment.getExternalStorageDirectory() + File.separator + "myH5camera" + File.separator + "aaa.jpg";
@JavascriptInterface
public void takePhoto() {
// 调用系统摄像头
Log.d("调用前置摄像头：","");
startCamera(TAKE_PHOTO, filePath);
}
private void startCamera(int type, String imgName) {
File filePath = new File(imgName);
try {
if (!filePath.exists()) {
filePath.getParentFile().mkdirs();
}
} catch (Exception e) {
e.printStackTrace();
}
Uri imageUri;
/**
* android7.0及以上
*/
if (Build.VERSION.SDK_INT >= 24) {
imageUri = FileProvider.getUriForFile(mContext, mActivity.getPackageName() + ".provider", filePath);
} else {
imageUri = Uri.fromFile(filePath);
}
//启动相机程序
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
mActivity.startActivityForResult(intent, type);
}
}
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