所以我的问题是我需要将图像从文件路径转换为base64，但是当我转换返回的String时，这就是我所看到的：
base64 String to image
我需要从真实图像中显示真实的base64字符串。
这是我的代码：
package com.example.myapplication;
import android.Manifest;
import android.app.Activity;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.content.FileProvider;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Base64;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import org.w3c.dom.Text;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.text.SimpleDateFormat;
import java.util.Date;
import static android.os.Environment.getExternalStoragePublicDirectory;
public class MainActivity extends AppCompatActivity {
ImageView ivImage;
String pathToFile;
Integer REQUEST_CAMERA=1, SELECT_FILE=0;
File image;
TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
textView=(TextView)findViewById(R.id.textV);
if(Build.VERSION.SDK_INT >= 23)
{
requestPermissions(new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE} , 2);
}
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
/*Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();*/
SelectImage();
}
});
}
private void SelectImage()
{
final CharSequence[] items = {"Camera", "Gallery", "Cancel"};
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setTitle("Add Image");
builder.setItems(items, new DialogInterface.OnClickListener(){
@Override
public void onClick(DialogInterface dialogInterface, int i )
{
if(items[i].equals("Camera"))
{
dispatchPictureTakerAction();
}else if(items[i].equals("Gallery"))
{
Intent intent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
intent.setType("image/*");
startActivityForResult(intent.createChooser(intent,"Select File"), SELECT_FILE);
}else if(items[i].equals("Cancel"))
{
dialogInterface.dismiss();
}
}
});
builder.show();
}
private void dispatchPictureTakerAction()
{
Intent takePic = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if(takePic.resolveActivity(getPackageManager()) != null)
{
File photoFile = null;
photoFile = createPhotoFile();
if(photoFile != null)
{
pathToFile = photoFile.getAbsolutePath();
Uri photoUri = FileProvider.getUriForFile(MainActivity.this,"com.thecodecity.cameraandroid.fileprovider", photoFile);
takePic.putExtra(MediaStore.EXTRA_OUTPUT, photoUri);
startActivityForResult(takePic,1);
}
}
}
private File createPhotoFile()
{
String name = new SimpleDateFormat("yyyyMMdd_MMmmss").format(new Date());
File storageDir = getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
image = null;
try
{
image = File.createTempFile(name, ".jpg", storageDir);
}catch(Exception e)
{
Log.d("mylog", "Except : " + e.toString());
}
return image ;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
super.onActivityResult(requestCode,resultCode,data);
if(resultCode == Activity.RESULT_OK)
{
if(requestCode == REQUEST_CAMERA)
{
Bitmap bmp = BitmapFactory.decodeFile(pathToFile);
textView.setText(getFileToByte(pathToFile));
}else if(requestCode == SELECT_FILE)
{
Uri selectedImageUri = data.getData();
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static String getFileToByte(String filePath){
Bitmap bmp = null;
ByteArrayOutputStream bos = null;
byte[] bt = null;
String encodeString = null;
try{
bmp = BitmapFactory.decodeFile(filePath);
bos = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.JPEG, 100, bos);
bt = bos.toByteArray();
encodeString = Base64.encodeToString(bt, Base64.DEFAULT);
}catch (Exception e){
e.printStackTrace();
}
return encodeString;
}
private String encodedImage(Bitmap bm)
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG,100,baos);
byte[] b = baos.toByteArray();
String encImage = Base64.encodeToString(b, Base64.DEFAULT);
return encImage;
}
}
这是我转换为base64时的结果
/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAEBAQEBAQ EBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEB AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQH/2wBDAQEBAQEBAQEBAQEBAQEBAQEBAQEB AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQ EBAQEBAQEBAQEBAQEBAQEBAQEBAQH/ WAARCBBADDADASIA AhEBAXEB/ 8QAGwAAAwEBAQEBAAAAAAAAAAAAAQIDBAAFCgn/ XABVEAACAAMEBgclAgEEAQIBAhcB AgMREGAhljETMKFRYfAjQnGBkaGxMO NTY8HR4fFSC4MEYpOjs3LDOXSC4/
答案 0 :(得分：1)
您可以按照以下步骤获取base64：
ByteArrayOutputStream bao = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.JPEG, 100, bao);
byte [] ba = bao.toByteArray();
String yourBase64= Base64.encodeToString(ba,Base64.DEFAULT);
答案 1 :(得分：0)
使用位图，您可以像这样获得Base64：
ByteArrayOutputStream bos = new ByteArrayOutputStream();
yourBitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
String encodeString = Base64.encodeToString(bos.toByteArray(), Base64.DEFAULT);
或者您可以像这样从byte[]获得File：
public static byte[] readBytesFromFile(File file) throws IOException {
InputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
// You cannot create an array using a long type.
// It needs to be an int type.
// Before converting to an int type, check
// to ensure that file is not larger than Integer.MAX_VALUE.
if (length > Integer.MAX_VALUE) {
throw new IOException("Could not completely read file " + file.getName() + " as it is too long (" + length + " bytes, max supported " + Integer.MAX_VALUE + ")");
}
// Create the byte array to hold the data
byte[] bytes = new byte[(int) length];
// Read in the bytes
int offset = 0;
int numRead = 0;
while (offset < bytes.length && (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
offset += numRead;
}
// Ensure all the bytes have been read in
if (offset < bytes.length) {
throw new IOException("Could not completely read file " + file.getName());
}
// Close the input stream and return bytes
is.close();
return bytes;
}