[英]how to send base64 string in android?
我正在尝试制作HTML
页面上有一个“按钮”的液压应用程序。每当我单击该按钮时,我都想调用android代码函数(当我从javascript调用test
函数时,它工作正常) 。现在,我想单击按钮捕获图像单击我从URL下面获取帮助。 从相机捕获图像并在活动中显示我确实喜欢这个包com.example.myapp.myapplication;
import android.Manifest;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.util.Base64;
import android.util.Log;
import android.webkit.JavascriptInterface;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.widget.Toast;
import java.io.ByteArrayOutputStream;
public class MainActivity extends AppCompatActivity {
private static final int CAMERA_REQUEST = 1888;
private static final int MY_CAMERA_PERMISSION_CODE = 100;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WebView webView = (WebView) findViewById(R.id.webview);
// webView.loadUrl("http://1.5.20.97:3671");
webView.loadUrl("http://15.16.74.160:6019");
JavaScriptInterface jsInterface = new JavaScriptInterface(this);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebChromeClient(new WebChromeClient());
webView.addJavascriptInterface(jsInterface, "JSInterface");
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == MY_CAMERA_PERMISSION_CODE) {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
} else {
Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();
}
}
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK) {
Bitmap photo = (Bitmap) data.getExtras().get("data");
// Log.d("My map",photo,"");
}
}
public void checkTest(){
if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_PERMISSION_CODE);
} else {
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
}
}
class JavaScriptInterface {
private MainActivity activity;
public JavaScriptInterface(MainActivity activity) {
this.activity = activity;
}
@JavascriptInterface
public void test() {
this.activity.checkTest();
}
@JavascriptInterface
public String bitMapToBase64()
{
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
//add support for jpg and more.
bitMap.compress(Bitmap.CompressFormat.PNG, 50, byteArrayOutputStream);
byte[] byteArray = byteArrayOutputStream .toByteArray();
String encoded = Base64.encodeToString(byteArray, Base64.DEFAULT);
return encoded;
}
}
我正在尝试调用打开相机并捕获图像并返回到javascript的android函数。
在JavaScript上,我正在这样调用函数
console.log(window.JSInterface.test())
因此,当您从相机捕获图像时要返回到webView
,请将onActivityResult
方法更改为
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK) {
photo = (Bitmap) data.getExtras().get("data");
if (webView != null)
webView.loadUrl("http://125.16.74.160:30019");
}
}
同样,您应该将bitmap
声明为这样的全局静态变量
公共静态位图照片;
然后bitMapToBase64
变成这样
@JavascriptInterface
public String bitMapToBase64()
{
if (MainActivity.photo != null) {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
//add support for jpg and more.
MainActivity.photo.compress(Bitmap.CompressFormat.PNG, 50, byteArrayOutputStream);
byte[] byteArray = byteArrayOutputStream .toByteArray();
String encoded = Base64.encodeToString(byteArray, Base64.DEFAULT);
return encoded;
}
return "null image";
}
在javascript端,您检查bitMapToBase64函数的返回值是否不同于“空图像”,您可以将base64图像转换为Blob或图像对象,并在div中显示它。
这是一个如何将base64字符串转换为图像对象并将其附加到您的身体的示例
var image = new Image();
image.src = 'data:image/png;base64,iVBORw0K...';
document.body.appendChild(image);
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